Jump to content
Sign in to follow this  
Franklinstein

601 processor replacement experiments

Recommended Posts

That was a booboo on my part last night, didn't realize the 750CX was one of the CPUs you posted as available. Booboo'd again this morning, it happens. Too dopey tonight to make sense of questcomp.com? Got linkage to the 750 series? Is that even the correct site?

 

I guess it all boils down to signal compatibility. Peeked at the 603e docs collected in the G3 info folder and found three different versions with different clock multiplier setups and I have no idea which type is in the processor module donor. At this point I'm going to bet I'm stuck with a 4x multiplier which revs that 200MHz part transplanted into the 2300c all the way up to  .  .  . 100MHz. :blink: My brain hurts  .  .  .

 

edit  .  .  .  bourbon helped.

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites
4 hours ago, trag said:

jt, why salvage 750CX when you can buy them new and undamaged and with fresh balls fro about $20 from Quest?  

I hate page break discontinuity: see booboo notice above.

Quote

Though, if you're going to the trouble to build an adapter board, unless the height is an obstacle, I'd use the 750GL instead.    20X  multiplier, instead of 10X, and four times the L2 cache.  True, the chip will cost 2X, ~$40, but compared to the amount of effort that would go into adapting either chip, the extra $20 is not significant.

You'd said the 750GL etc were 292 pin BGA packages and that the 750CX is a 256 pin BGA. That'a just one contact more than the 603e which came in "240-pin ceramic quad flat pack (CQFP) or 255 ceramic ball grid array." So I was guessing the later versions wouldn't work. A 10x multiplier cranks the 2300c up to 250MHz with 256K of L2 Cache. My 1400c has a CrescendoPB/G3/466MHz/1MB, so getting my precious Duo up to about half of that would be a major achievement  .  .  .  if only I were up to that task. :-/

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites
12 hours ago, Trash80toHP_Mini said:

I hate page break discontinuity: see booboo notice above.

You'd said the 750GL etc were 292 pin BGA packages and that the 750CX is a 256 pin BGA. That'a just one contact more than the 603e which came in "240-pin ceramic quad flat pack (CQFP) or 255 ceramic ball grid array." So I was guessing the later versions wouldn't work. A 10x multiplier cranks the 2300c up to 250MHz with 256K of L2 Cache. My 1400c has a CrescendoPB/G3/466MHz/1MB, so getting my precious Duo up to about half of that would be a major achievement  .  .  .  if only I were up to that task. :-/

 

It's one more ball, but the packages for the 750CX and the 603/740 are different sizes, pitches.    So you cannot solder a cx in place of a 603.  

 

So, you would need to make an interstitial board.   As long as you're building a special adapter board, you may as well build it for the best chip available.

Share this post


Link to post
Share on other sites

Not really applicable as I'm not really thinking about BGA to BGA adapters. I'm really only interested in BGA to QFP 603e pads. If I get around to a layout attempt, I may as well try Ball to Ball as you've suggested as well. Do you really think 292 BGA might be compatible with 240 pin QFP 603e? Might there merely be more ground lines due to the tighter grid pitch pattern?

Share this post


Link to post
Share on other sites

All these chips do 601X bus, so they are more or less compatible.    

 

On Quest's website, in the search box at the top, try ibm25ppc750 as a search term.    There's a box near (above?) the search box for "in stock".   I usually click that as well.   It must be clicked before the search.

Share this post


Link to post
Share on other sites

Dead slow at work tonight, so I checked out datasheets. 750CX is looking much better than the 750FX.

 

Power filtering looks easier and the decoupling recommendations are only severe. Decoupling recommendations for the 750FX are downright draconian. No way to meet them on an adapter for a PowerBook that I can see. The most important of caps are likely the ones dead center under the die. Spec is to put the decoupling cap electrodes directly opposite their corresponding BGA pins on the underside of the board where possible or on short paths from thru-vias adjacent to the decoupling caps.

 

With inverted die surrounded by its box of contacts, it might be possible to achieve adequate decoupling for the 750CX by nibbling away at it from the edges? 10x multiplier of the 750CX cuts the clock down to 250MHz as opposed to 500MHz for the 750FX. But the lower clock means reduced decoupling requirements and the possibility of meeting them. That 250MHz cup would be brimming over, not half empty. The doubled L2 of the 750FX would have been nice, but in a machine with none, I think 256K of L2 would do.

 

Still not up to the task now by any means, if ever. But feasibility study is fun all on its ownsome. :approve:

Share this post


Link to post
Share on other sites

@trag Now I'm wondering if decoupling caps present on the 100MHz 603e of the 2300c might be sufficient for running a 600MHz 750CX at 250MHz?

 

Haven't even looked for voltage differential complications or function of that one extra ball. I guess it's back to basics in the kibosh hunt.

Share this post


Link to post
Share on other sites

Back on topic!

On 10/12/2018 at 10:55 PM, Franklinstein said:

I wonder if they also redesigned the 601v to be intentionally disruptive? I am guessing no, since the whole PPC project was in a state of turmoil for the first few years as they fine-tuned the platform. I mean, the PPC 740 is both pin and signal compatible with the BGA 603e so at least if they were being vexatious at first they changed their mind in later years.

Not sure about that, the same thing appears to happen in the 740/750 generations.

On 10/12/2018 at 2:07 PM, Gorgonops said:

Looking at the datasheets for the 604 and 601 it looks like it's a hard no. They're both 304 pin packages but the pin assignments don't match up at all. (Like, literally, the same pin is a voltage supply on one but a ground on the other, and the signals are likewise completely scrambled. It almost looks like they intentionally made them as incompatible as humanly possible.) So at the very minimum you'd need some sort of adapter board.

Looking at the decoupling recommendations for the two 750 versions above, scrambling the signals around in order to rearrange power and ground might have been done out of necessity as the rising clocks raised the bar for noise containment.

 

@FranklinsteinThe BGA to BGA adapters you were talking about would be a lot more practical for desktop/tower boards than QFP to BGA. Doing the adaptation on a smaller board with a larger board balled to that inverted pagoda style offers double the layers from the same multilayer prototype run. Increased surface area on the upper surface for dohickys of all sorts becomes available The possibility of placing SMD caps on the underside of the upper board in between like parts on the logic board cmight work as well. Funky outlines of the two adapter levels and underside components would make for a delicious bar puzzle design exercise.

Share this post


Link to post
Share on other sites

Slow again last night , so I worked out 750CX to 603e signal differentiation.  There are about 28 signals on the 603e pinout that ate missing from the simplified 750CX pinout. From the looks of it at this point they can be ignored. They appear to be related to external L2 implementation.

_____________________________________________________________________________________________________

edit: sorry about the formatting, I guess I'll never get the manual quote codes figured out for the new forum software. The irritating situation where you can't edit a manually encoded quote to fix encoding errors seems like it will ensure that. :-/

_____________________________________________________________________________________________________

 

One 750CX signal is a combination of two lines on the 603e pinout, spec says it needs to be held high:

Quote

p.39 

7.9.4  DBWO/L2_TSTCLC

One pin has two functions: DBWO and L2_TSTCLK dependent upon the LSSD_MODE pin. When the LSSD_MODE pin is low, the DBWO/L2_TSTCLK pin is set to L2_TSTCLK function which is used during the manufacturing process for testing.
 
When the LSSD_MODE pin is pulled to the high state, the DBWO/L2_TSTCLK pin is set to DBWO which is identical to those descriptions given in earlier versions of the PowerPC 750CX RISC Microprocessor’s User’s Manuals.

Only one 750CX signal is missing from the 603e pinout:

 

p. 38 

7.9.3  1.8V and 2.5V I/O Signal Support

Selection between 1.8V and 2.5V I/O is accomplished using the BVSEL pin. If BVSEL is set low then the 1.8V mode is enabled. If BVSEL is set high, then the 2.5V mode is enabled. Due to bus timings restrictions, only uniprocessor implementations are recommended. No multiprocessor support is advised.

So it's back to voltage level basics to determine compatibility. Signals I'm comfortable with, voltages are a brand new concern. Little help?

 

Data pulled from these two PDFs:

PowerPC 750CX Microprocessor Datasheet - 43 pages - June 2001

PowerPC 603e Hardware Spec - 40 pages - November 1996

 

 

PowerPC 603e User's Manual - 433 pages - September 1995

 

 
Po
Edited by Trash80toHP_Mini
I'm an idiot. :-/

Share this post


Link to post
Share on other sites

Managed to kill the second quote above trying to edit the post. ::)

 

Only one 750CX signal is missing from the 603e pinout:

Quotation___________________________________________________
p. 38   7.9.3   1.8V and 2.5V I/O Signal Support
Selection between 1.8V and 2.5V I/O is accomplished using the BVSEL pin. If BVSEL is set low then the 1.8V mode is enabled. If BVSEL is set high, then the 2.5V mode is enabled. Due to bus timings restrictions, only uniprocessor implementations are recommended. No multiprocessor support is advised.

__________________________________________________________

 

So it's back to voltage level basics to determine compatibility. Signals I'm comfortable with, voltages are a brand new concern. Little help?

 

 

edit: IBM PowerPC® 750CX/750 RISC Microprocessor User’s Manual

 

http://softpixel.com/~cwright/papers/tech/750CX_CXe_UM_prel_V1.1_09May02.pdf

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites

Back on topic:

 

@Franklinstein your mention of the dual voltage transplant friendliness of the PowerMac 8100 piqued my curiosity.. I pulled my spare Radius 81/110 board out of its PEx drawer nest to have a quick look. It appears to be a not overly hostile, if not BGA to BGA 750FX adapter friendly design. There are scads of decoupling caps directly under the 601 ball contacts that might be rearranged to take care of much, if not all requirements of the incredibly QFP adapter hostile 750FX package.

 

Given the external L2 oriented similarities the 601 has with the 603e, there may be more than enough decaps to have some left over! I'll take a WAG that leaving the L2 DIMM slot empty will be enough to remove any conflicts. I wonder if a 1GHz 750GX might be floating around available somewhere for my metal can monster? [}:)]

 

 

edit: Benchmarking a RadiusMonsterBox/750GX/1GHz against 1997's Beige G3 would be interesting. 37MHz vs. 66MHz system bus bottleneck for memory access might be attenuated by the extra 512K of L2, the 4x clock bump over the stock BG3 might give the 81/110 a run for the money? 

 

http://datasheets.chipdb.org/IBM/PowerPC/750/PowerPC-750GX.pdf

 

 

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites

Well there's another booboo. 601's not BGA, thought it looked odd from the edge but didn't put the multiple diopter readers on until just now. So the decaps and resistors clumped under its footprint probably aren't close enough to work with the 760FX, bummer. But you never know and the 600MHz 750CX might just work.

 

Partial PPC family chart: https://www.okqubit.net/ppchikaku.html

 

PowerPC 601 Technical Summary - Advance Information - 32 pages - November 1993

PowerPC 601 User Manual - 777pages - 1995

 

Share this post


Link to post
Share on other sites

Back in here and once again I'm totally confuzzled! I was thinking earlier today that a version of the G4 was compatible with one of the G3 CPUs. IIRC that's the Wegener Media Pismo G4 hack. Looking into the possibility of doing the same type of thing with a Crescendo PB G3 for the 1400 just for the hell of it. I've got another G3 Accelerator from NewerTech(?) if it's a better match.

 

Still gotta get all these procswappin' thread links together in one topic for easier reference. Crazy stuff! :wacko:

Share this post


Link to post
Share on other sites

The support chips for the original Power Macs were all the same and rated to at least 40MHz (and were used as such in the 7100/80, 8100/80, and 9150/80 and 120), so simply swap out the clock crystal to change the base speed. I did that on an 8115/110 and it now runs at 120MHz with no problems. Not much of a noticeable performance boost though, but it's well within the margin of safety (by my definition: anything within 10% of original rated speed is "safe", 20% is "maybe", >30% is "gonna melt unless I install these huge, expensive, loud coolers").

 

I've seen a couple references to people swapping a 7400 onto a 750-based Pismo CPU card but I'm not sure how they do it. I haven't compared the 7400's pin-out to the 750's because I simply assumed they were different (IIRC the 7400 has a wider address and/or data bus than the 750). It's possible that the 7400 and 750 share the same or close enough pin-out to share a similar mount but at this point I can only speculate. If they are interchangeable, I know you won't be able to do this with any chips other than the 750/750L and the 7400 or 7410; the later chips are most definitely incompatible.

Share this post


Link to post
Share on other sites

Curious, I'll have dive back into the PDF docs once again it seems.

 

It's looking like my theoretical interstitial QFP to BGA adapter could be the way to go. The cache deprived 1400/117MHz processor card would be the best candidate as there would be no slow L2 cache complications. Only two tiny caps stand in a 23mm wide pathway between another two pairs of caps into the "cache overhang" space of the higher end processor cards with cache. A pair of holes in the adapter PCB takes care of that clearance problem with plenty of area left on the multiple layers for the lines required for support components/voltage doohickeys.

 

The only complication would be that such an extension buries the QFP pads on that side of the adapter. Such may not be a problem as higher temperature hot air installation would be possible. There are ZERO active components on the processor card. Every component is a silk screen layer identified cap, resistor or resistor pack save a curious boxy two connection somethingorother. I'll need to buz the connections, WAG would be a voltage converter?

 

This brings up a second approach that's nontrivial at best and outright insane at worst. The 117MHz card appears to be done in four layers and amounts to an interboard connectors to QFP adapter with a workable sprinkling of power leveling and termination(?) glue on board. Caffeine deprived morning musing today would be to design a new processor card for the BGA G4 of choice with cache on die instead of the interstitial adapter. As in the statement above, the cantilevered "cache extension" provides more than adequate PCB real estate for support components.

 

If the high 32 bits of a 64bit CPU were terminated would that suffice to use such a beast on a 32bit bus? We're talking shades of the LC's lamed 32bit 68020 running on a 16bit bus. A two generation CPU upgrade with cache on die at a HIGH bus multiplier on the 1400's 32bit bus hardly qualifies as "laming." [}:)]

 

I hope this makes some kind of sense? :blink:

 

 

*** I'm beginning to wonder if Wegener employed an interstitial BGA to BGA adapter for theig Pismo G4 upgrades?

 

 

edit: designing a new processor card with CPU specific support components would almost have to be a more practical approach (and far more efficient) than an interstitial adapter board. BGA to board interconnects on either side has to be easier than the spaghetti mess of BGA to QFP pads on all four sides. I wonder if the interboard connectors are still available? Donor card harvest/reinstallation on the G4 adapter ought to be easy enough, no?

Edited by Trash80toHP_Mini
I'm an idiot. :-/

Share this post


Link to post
Share on other sites
18 hours ago, Franklinstein said:

I've seen a couple references to people swapping a 7400 onto a 750-based Pismo CPU card but I'm not sure how they do it. I haven't compared the 7400's pin-out to the 750's because I simply assumed they were different (IIRC the 7400 has a wider address and/or data bus than the 750). It's possible that the 7400 and 750 share the same or close enough pin-out to share a similar mount but at this point I can only speculate. If they are interchangeable, I know you won't be able to do this with any chips other than the 750/750L and the 7400 or 7410; the later chips are most definitely incompatible.

I found a spec sheet on the 7410 and it's out of the running, the PLL settings/multiplier table lists no support for a 33MHz system bus.

The 7400 multipliers only go up to 8x in the spec in one place, but the PLL settings table also shows 9x, still too slow to be in contention unless a 300MHz G4 stomps a 466MHz G3?

 

@trag  Quest lists the PPC750FX-GB0132T as available, but I see no spec for the max processor speed? Is that the 800MHz part you listed? The PPC750L-GB450A2 is a bit slower than my Sonnet 466/1MB. Earlier you said:

Quote

They have some (7) 750FX at  800 MHz for $32.50.  That's pretty good.   292 pin BGA (21mm X 21mm).   The 750FX has up to a 20X bus multiplier.


Anyone know how the 750GL differs from the 750GX?    They have 81 750GL for $34.50 - $39.    Same package as the 750FX and also up to 20X multiplier.   The GL has a 1MB L2 cache like the GX...

The 292 pin versions appear to have cache lines broken out, whereas the 256 pin (740 and 750CX?) CPUs don't as I recall from reading earlier tonight. If the CPUs you listed have 1MB of L2 on die, those cache lines must be for an L3 setup we never saw in a Mac because of the switch to G4? What was the fastest G3 Apple shipped anyway? If I can disable/terminate those L3 lines on a 292 pin package, a G3 with 1MB of on die L2 running on a 20x multiplier at 666MHz would do nicely for the 1400 unless a G4 candidate can be identified. Don't recall, does the on die L2 run on the CPU clock or on a divider?

 

Found another G3 in stock: PPC750FX_GB1033T_FB1033T but the speed (1033MHz?) would be wasted. 33.3MHz bus x 20 = 666MHz ceiling for a PB1400 CPU and heaven only knows what they'd cost if I'm deciphering the coding correctly? Way beyond my wildest dreams, but with that imaginary L3 implemented one might make a nice GigaHertz L2 Slot Accelerator for the 50MHz bus of the TAM. [}:)]

 

OK, well past time for an egg nog! [:)]

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites

Well, I don't have much to add here, but my understanding is that one of the few significant advantages the G4 has over the G3 is the former's AltiVec engine that can boost certain things like Photoshop plugins and I believe Mac OS X makes use of it, particularly in Tiger. The G4 can also support multiprocessing (SMP) (irrelevant here, but still of potential interest in general), whereas the G3, oddly, cannot.

 

c

Share this post


Link to post
Share on other sites
8 hours ago, Trash80toHP_Mini said:

Curious, I'll have dive back into the PDF docs once again it seems.

 

It's looking like my theoretical interstitial QFP to BGA adapter could be the way to go. The cache deprived 1400/117MHz processor card would be the best candidate as there would be no slow L2 cache complications. Only two tiny caps stand in a 23mm wide pathway between another two pairs of caps into the "cache overhang" space of the higher end processor cards with cache. A pair of holes in the adapter PCB takes care of that clearance problem with plenty of area left on the multiple layers for the lines required for support components/voltage doohickeys.

 

The only complication would be that such an extension buries the QFP pads on that side of the adapter. Such may not be a problem as higher temperature hot air installation would be possible. There are ZERO active components on the processor card. Every component is a silk screen layer identified cap, resistor or resistor pack save a curious boxy two connection somethingorother. I'll need to buz the connections, WAG would be a voltage converter?

 

This brings up a second approach that's nontrivial at best and outright insane at worst. The 117MHz card appears to be done in four layers and amounts to an interboard connectors to QFP adapter with a workable sprinkling of power leveling and termination(?) glue on board. Caffeine deprived morning musing today would be to design a new processor card for the BGA G4 of choice with cache on die instead of the interstitial adapter. As in the statement above, the cantilevered "cache extension" provides more than adequate PCB real estate for support components.

 

If the high 32 bits of a 64bit CPU were terminated would that suffice to use such a beast on a 32bit bus? We're talking shades of the LC's lamed 32bit 68020 running on a 16bit bus. A two generation CPU upgrade with cache on die at a HIGH bus multiplier on the 1400's 32bit bus hardly qualifies as "laming." [}:)]

 

I hope this makes some kind of sense? :blink:

 

 

*** I'm beginning to wonder if Wegener employed an interstitial BGA to BGA adapter for theig Pismo G4 upgrades?

 

 

edit: designing a new processor card with CPU specific support components would almost have to be a more practical approach (and far more efficient) than an interstitial adapter board. BGA to board interconnects on either side has to be easier than the spaghetti mess of BGA to QFP pads on all four sides. I wonder if the interboard connectors are still available? Donor card harvest/reinstallation on the G4 adapter ought to be easy enough, no?

The 603 was designed to allow selection of either 32 or 64 external data lines; the 7400 is possibly also configurable to use fewer data lines, but I haven't read the manual. In the 1400 (and its progenitors, the PB 5300/2300) the 603e lives on a 32-bit data bus. Since 750 upgrades work in the 1400 (and are derived from the 603) it stands to reason that the 750 is also configurable to operate with a 32-bit data bus. 

 

Just because something doesn't officially support a given bus speed doesn't mean it won't. For example, the 37.5MHz bus in the 52/62xx computers is an unsupported configuration for the 603; the 75MHz part was supposed to be operated at 3x on a 25MHz bus (the original 603 does not support half multipliers). Officially supported bus speeds for the 603 are 16, 20, 25, 33, 40, 50, 60, and 66MHz. It's entirely possible the 7440 will run on a 33MHz bus, but depending on its max multiplier, I don't see it going much over 667MHz (20x bus speed). 

 

I know that a good number of the PowerBook G3 upgrade cards were custom built with Flash chips instead of Apple-produced ROM chips, so they're out there. I don't know how they got around that. Maybe because they were designed for use exclusively in Apple products? Maybe they operated exclusively on trade-ins? Maybe they paid a royalty? 

Share this post


Link to post
Share on other sites
Just now, Trash80toHP_Mini said:

I found a spec sheet on the 7410 and it's out of the running, the PLL settings/multiplier table lists no support for a 33MHz system bus.

The 7400 multipliers only go up to 8x in the spec in one place, but the PLL settings table also shows 9x, still too slow to be in contention unless a 300MHz G4 stomps a 466MHz G3?

 

@trag  Quest lists the PPC750FX-GB0132T as available, but I see no spec for the max processor speed? Is that the 800MHz part you listed? The PPC750L-GB450A2 is a bit slower than my Sonnet 466/1MB. Earlier you said:

The 292 pin versions appear to have cache lines broken out, whereas the 256 pin (740 and 750CX?) CPUs don't as I recall from reading earlier tonight. If the CPUs you listed have 1MB of L2 on die, those cache lines must be for an L3 setup we never saw in a Mac because of the switch to G4? What was the fastest G3 Apple shipped anyway? If I can disable/terminate those L3 lines on a 292 pin package, a G3 with 1MB of on die L2 running on a 20x multiplier at 666MHz would do nicely for the 1400 unless a G4 candidate can be identified. Don't recall, does the on die L2 run on the CPU clock or on a divider?

 

Found another G3 in stock: PPC750FX_GB1033T_FB1033T but the speed (1033MHz?) would be wasted. 33.3MHz bus x 20 = 666MHz ceiling for a PB1400 CPU and heaven only knows what they'd cost if I'm deciphering the coding correctly? Way beyond my wildest dreams, but with that imaginary L3 implemented one might make a nice GigaHertz L2 Slot Accelerator for the 50MHz bus of the TAM. [}:)]

 

OK, well past time for an egg nog! [:)]

I'm out of nog :(

 

I put my comment about the unsupported bus speeds in the wrong section so see above.

 

The 750GX was originally available at 1.2GHz or better with a maximum 200MHz bus speed, something Apple never implemented in a G3 (I don't think they went over 100MHz). I think the 750FX also could drive a 200MHz bus in some versions and it was available up to at least 1GHz. 

 

No 750 variant ever supported L3 cache.

 

The 740 does not support a backside L2 cache, but assuming it is 100% compatible with the 603e, it will support a bus-level L2 cache. The 750 has an integrated L2 cache controller to support a variable high-speed backside L2 cache, though the extra pins required make it no longer pin-compatible with the 603e. The 750CX brought the cache on-die (256k at full speed) so it no longer had need of the L2 cache pins of the original 750, yet it was also not pin-compatible with the 750 or 603e. The 750FX was a major improvement including new power-saving features, more L2 cache (512k), and higher clock and bus speeds; it was also not pin-compatible with any of its predecessors. The 750GX was a minor enhancement of the FX consisting mostly of higher clock speeds and another doubling of the L2 cache (to 1MB); it is pin-compatible with the 750FX.

 

The fastest Macs Apple shipped with G3s were: B&W G3 at 450MHz (750L), PowerBook G3 Pismo at 500MHz (750L), iMac SE at 700MHz (750CX), and the opaque white iBook G3 at 900MHz (750FX).

 

I would personally enjoy a 1GHz L2-style 750GX upgrade, if we're thinking about taking orders. An 800MHz variant would probably be better value (the law of diminishing returns and all) but if we're going to the trouble, may as well go all the way.

Share this post


Link to post
Share on other sites
Just now, CC_333 said:

Well, I don't have much to add here, but my understanding is that one of the few significant advantages the G4 has over the G3 is the former's AltiVec engine that can boost certain things like Photoshop plugins and I believe Mac OS X makes use of it, particularly in Tiger. The G4 can also support multiprocessing (SMP) (irrelevant here, but still of potential interest in general), whereas the G3, oddly, cannot.

AltiVec, additional and/or wider internal sections (decoders, ALUs, etc), and full MESI support for multiprocessing were the 7400's advantages over the 750. Like the 603, the 750 only had partial multi-processing support (only MEI instead of the full MESI suite), so it was unsuitable for such applications.

Clock-for-clock the 7400 is faster than the 750, but not by much; unless an app is AltiVec-enabled, most tasks aren't noticeably faster, while the 7400's greater power consumption and heat output generally are. Unless you're doing nothing but A/V work (PhotoShop, FCP, iMovie, iTunes, whatever else may have AltiVec extensions) there's no real point to a G4 upgrade for Classic Mac OS, especially since the all-important AltiVec support requires OS 9 or later.

Share this post


Link to post
Share on other sites

Good news: I finally looked up the specs for the 750 and the 7400, and they're basically pin compatible: they're both 360-pin BGA devices and all but 10 pins are the same. The 10 different pins may be inconsequential, and it would appear that they are, given that people have done swaps without apparent issue. The only concern would be boot-level software support, if it's required. A closer inspection of those Sonnet G4 upgrades suggests that they have Apple ROMs and additional Flash devices which may hold patches to support the new 7400, but then there's a seller on Yahoo! that advertises a simple swap of the processors on a Pismo card. Maybe a patch disk is included? I dunno.

Share this post


Link to post
Share on other sites

Upgrading PCI PowerMac 5/6x00 L2 upgrades (was) Sonnet Clocker II - gotta dig up the Sonner Clocker II thread.

_____  Bolle joined that thread with a link to info on his work from a year ago in 's @max1zzz's work from two years ago

iMac G3 (Rev A -> C) G4 CPU Upgrade

_______________  I'll find all the ProcSwap threads eventually, help would be appreciated.

 

Lets see, I'm only interested in machines that run OS9 on the 603e at this point, so:

 

I settled on a redesign of the 1400's 117 MHz processor card for simplicity's sake. LOL!

____  building a BGA to CPU card's board interconnect is the most flexible experiment

________  no interstertil adapter experimentation involved

____  No cache problems to crop up as in max's thread

____  It's a driver free swap of the CPU board

________  as it's currently proposed anyway

____  there shouldn't be any ROM complications, it'll "just work" or not as the case may be

________  only signal compatibility at boot would be required as I see it anyway

 

No OSX means ALTIVEC's not a requirement

____no sane person does supported graphics work on 603e

____a higher multiplier (20x) on a G3 trumps a lower multiplier G4 that won't crank to 666MHZ on a 33.3MHz bus

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites

Ran out of edit time so please excuse the spelling and worse than usual stream of incoherence above. Didn't get a chance to say thanks much for your help and research, Franklinstein. @trag too of course.

 

 

@Cory5412 it's probably about time to break my ridiculous 603e tangent off this 601 topic and into its own hacks thread like the last one. Maybe something like "1400 Processor Card - New Build Proposal?"

Share this post


Link to post
Share on other sites

:lol: Shutting my brain down in the shower works even after caffeine has kicked in. Just realized the proposed 1400 processor card development amounts to a BGA to BGA interstitial adapter PCB prototype on much a larger scale. QFP to BGA can wait, a BGA to BGA CPU upgrade on a 50MHz bus could be very interesting indeed.

 

Edited by Trash80toHP_Mini

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×