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

[LightBulbFun]

Very nice! Thanks they are appreciated. good to see you got leopard optimised i have a Leo OS9 combined image i made and i disabled spot light for that reason as indexing will just eat the CPU. indeed an SSD should perk it up a bit I had my Pismo fitted with a 16GB fast CF card for a little while (before i needed the card elsewhere) that helped heh.

in regards to the picture thing I just upload my pictures to an album hosted elsewhere and then embed them in here I find it works well that way.

 

[belgaonkar]

@tarable- I tried the shadow killer thing, it works decently. I also disabled all the animations. The machine now sits at 4% idle. I can live with that.

I also did get a Geekbench score 

It got a 255 on GeekBench 2. A stock clamshell gets a 155 (according to everymac) on GB2.

 

[belgaonkar]

 

[LightBulbFun]

Very nice good to see you have the thermals under control enough to do a GB run, 255 thats a nice fast iBook clamshell Btw  I noticed your using GB2.2.0 thats the latest version for tiger but for leopard 2.2.7 is the latest

 

[belgaonkar]

Yeah, cause I plan to run the same exact version of GB on a non upgraded 300MHZ G3 running tiger. Currently installing 9.1 so I can upgrade the firmware.

 

[LightBulbFun]

cool sounds like a plan next big thing to try on a clamshell would be upgrading the L2 cache, trust me L2 cache makes a world of difference on these old Macs 512KB is much better then none but 1MB would be even better (the chip does support 2MB of L2 cache but im not sure if that was still done with just 2 cache chips/if 1MB chips where/are a thing)

 

[max1zzz]

I'm pretty sure the 7410 supports 8mbit cache chips, so you could use jsut two chips for 2mb

 

[LightBulbFun]

Yeah thats what i was thinking it would be case of finding 1MB Cache chips then im not sure if there rare or really common not looked into it actually LOL I know max linked to some cache chips earlier in the thread but i think those where 512KB cache chips? (all 750/7400/7410 Macs I have seen seemed to of used 2x256KB for 512KB L2 and 2x512KB for 1MB L2)

 

[TarableCode]

Are you changing the multi or bus speed to get the higher clocks?

I'd wonder how much you could push it that way if you desoldered the on board PC-66 memory, if possible.

 

[belgaonkar]

A stock clamshell get a 143 with the 300MHZ CPU and 578MB of Ram. The G4 swap and 578MB will give you a 255. Not bad.

The multiplier is being changed I believe.

 

[max1zzz]

Yep it's the multiplier I have been changing on both the iBooks and the iMac

 

[FacnyFreddy]

Sent my 500Mhz g3 pismo board off to the reballing service guy in Florida along with the 7410 chip from China. The 400Mhz is working fine and I ran through some quick tests and gaming to see if it ran into any issues... ZERO!

I'll post some results next month when I get it back. The 400MHz board will end up for sale later on when I get the other board back. (I've not touched the jumpers for overclocking... it was a system pull that I got off of fleabay for $20 to test this with)

Until next time...

 

[LightBulbFun]

Just figured id make a quick post about something I noticed in that I think the 333Mhz tray loading iMac Max did at the start of this May have used a 2.6v 750 it would explain why it ran so hot and never clocked past 400Mhz

my thinking for it being a 2.6V 750 is that despite it being stated that all 300Mhz and faster G3s use the 250Nm 1.9V core, the Chip in Maxes photos Looks like one of the first 750s the 266Mhz 750 from my G3 beige looks the same right down to the paper surround

its not the only 333Mhz tray loader i have seen like this,  https://www.journaldulapin.com/2014/07/10/booster-un-imac-g3-avec-ssd-processeur-et-memoire/ in this french blog the 333Mhz iMac CPU card has the same CPU as Maxes one and evident from the Screen shot of system profiler it has an early PVR (2.2 the same as the 266Mhz G3 from m G3 beige) it looks like early iMac G3 333Mhz tray loaders got the higher voltage older Rev 750. If you still have the Chip Max could you post a detailed Photo of the Die so i can read the markings that would tell me what chip it is exactly and tell me what Voltage/Gen Chip it is

however it seems like later iMac G3 trayloaders got the newer PPC750L from IBM, User Daniël Oosterhuis recently was taking apart a 333Mhz iMac G3 for a project and I asked for Pictures of the CPU Card and much to my surprise the CPU was an IBM PPC750L (the CPU also had the later style plastic foam surround but it had been removed by the time the picture was taken) it seems like Apple standardised on the IBM PPC750L after the first run of G3s the only deviation I have seen to this was 400-450Mhz XPC750s found in BW G3s all others 1999 and newer 750 Macs i have seen (Lombard, Pismo, iBook G3 clamshell, iMac slot loading etc) seem to all use the IBM PPC750L, this also means the Bellow CPU card should work well with 7410 fitted as it seems every PPC750L thats been replaced with a 7410 has worked well afterwords

what this also means is we might be able to figure out what sets the CPU Vcore on these iMac CPU Cards by comparing the one bellow to 2.6V card ill have to Ask Dan for some high detailed shots of both sides of the card (BTW the MPC106 on the other side dates to week 24 of 1999)

 

[max1zzz]

Hmm interesting, that means there must be voltage jumpers somewhere on that CPU card, I just need to find them!

Btw, do you have a link to the datasheet for the original 750? All the ones I have managed to find state the chips as having a 1.9-2.2v vcore (But these are more recent datasheets so may be for the L version even though the datasheets don't seem to state this)

 

[LightBulbFun]

indeed there must be voltage jumpers

here are some data sheets

http://datasheets.chipdb.org/IBM/PowerPC/7xx/PowerPC-740-750.pdf this ones for the PPC750L (LoneStar)

http://cache.nxp.com/assets/documents/data/en/fact-sheets/MPC750FACT.pdf?fsrch=1&sr=2&pageNum=1 handy not quite data sheet but still useful pdf for Motorolas 750s

http://www.nxp.com/assets/documents/data/en/data-sheets/MPC750EC.pdf and another one

 

[max1zzz]

Thanks For some reason I could never find anything quoteing 2.6v

 

[LightBulbFun]

Np most of the PDFs/product sheets are out there with a little bit of googling and use of the wayback machine

I have been keeping an eye on ebay for PPC CPUs and i spotted some 740s I might at some point grab one of those and see if I can slap it in to my PowerMac 4400 as the MPC740 and PowerPC 603ev are not only pin compatible there also close in core voltage

 

[max1zzz]

I would defiantly be interested to see that! Cheapest I have found 740's so far is about £33 a piece

 

[LightBulbFun]

Yeah thats what I have found as well hence the some point comment, at that price point it aint terribly high up on my priorities its a shame the 4400 is so buggy at a firmware level as its not a bad computer otherwise

 

[FacnyFreddy]

SUCCESS!!!  I upgraded my 500MHz G3 Pismo board to a G4 (7410 freescale) that I got off of fleabay for $15.
Proof is in the PNG, as we now say...


 
The toughest part was getting the Bootrom to upgrade to 4.1.8f5 and "stick". I had to sneak in a nearly dead PRAM battery and get it updated FIRST. Then zap the pram a couple of times for good measure. Pulled the main and pram batteries, and then reinsert the G4 board.
 
Next up, reballing a 533MHz G4 and overclocking it to 550MHz
(later this spring when I got more time and fewer projects to worry about)