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Interest in adapting 744x to 7400?

H

herd

6502
I was looking at the pin-out for the 7447 and I think it could be adapted to the 7400. Would people be interested in this? The main application I can see would be to install faster 7447 chips onto these boards for use in the Cube:

533cpub.jpg

These boards fit a Cube and are relatively available; the 7447 chips are also available.

The 7400 pin-out is also similar to the pin-out on a few versions of "G3" chips, so an adapter might allow 7447 chips to be installed on a few different G3 boards. The Pismo comes to mind, from this thread:

PPC750GX vs. PPC750GL?

I'm afraid I have missed the thread, but I have already made a replica of the PowerLogix 750GL accelerator... It however does not work as I did blow the VRM, so there's possibly a short somewhere in my design that I need to trace. Whaaaaat! This is amazing, how did you keep this under wraps...
68kmla.org 68kmla.org

Or maybe time would be better spent on recreating that adapter between the 750 and 750FX pin-outs? Those chips are also available and go up to 1GHz or so.
 
Would the interposer (I'm assuming) cause height issues needing significant mods to the G4 Cube heatsink?
 
Yes, I'm talking about an adapter. With a new board you could do whatever you want.

herd said:
In case the link goes dead, here are a couple of the pictures:

750FXa.jpg


750FXb.jpg
Click to expand...
 
ooh yeah id be very interested in seeing an interposer developed!

I know there is someone on here who has made a 7450-7455 BGA483 to BGA360 interposer to retrofit 7447A's and 7448's to existing DA/QS/MDD cards

but it would be awesome to see such an interposer for all the other PPC CPU's "sockets" :) esp something like the 750CX/CXe socket

would be lots of fun to cram a 7448 into an iBook G3 clamshell or iMac G3 :) and having an interposer for the original 750/7400 socket would be good for upgrading everything from Kanga's to Pismo's :) and it would also be neat to see the Above 750GX interpose recreated :)


(as a side note id love to see one of the BGA483-BGA360 interposed slapped onto a Sonnet 7450/7455 G4 7300-9600 upgrade card and make a completely Over powered 7448 based 9600 LOL)
 
LightBulbFun said:
ooh yeah id be very interested in seeing an interposer developed!

I know there is someone on here who has made a 7450-7455 BGA483 to BGA360 interposer to retrofit 7447A's and 7448's to existing DA/QS/MDD cards

but it would be awesome to see such an interposer for all the other PPC CPU's "sockets" :) esp something like the 750CX/CXe socket

would be lots of fun to cram a 7448 into an iBook G3 clamshell or iMac G3 :) and having an interposer for the original 750/7400 socket would be good for upgrading everything from Kanga's to Pismo's :) and it would also be neat to see the Above 750GX interpose recreated :)


(as a side note id love to see one of the BGA483-BGA360 interposed slapped onto a Sonnet 7450/7455 G4 7300-9600 upgrade card and make a completely Over powered 7448 based 9600 LOL)
Click to expand...
800MHz+ would be really nice on a 9600
 
LightBulbFun said:
ooh yeah id be very interested in seeing an interposer developed!

I know there is someone on here who has made a 7450-7455 BGA483 to BGA360 interposer to retrofit 7447A's and 7448's to existing DA/QS/MDD cards

but it would be awesome to see such an interposer for all the other PPC CPU's "sockets" :) esp something like the 750CX/CXe socket

would be lots of fun to cram a 7448 into an iBook G3 clamshell or iMac G3 :) and having an interposer for the original 750/7400 socket would be good for upgrading everything from Kanga's to Pismo's :) and it would also be neat to see the Above 750GX interpose recreated :)


(as a side note id love to see one of the BGA483-BGA360 interposed slapped onto a Sonnet 7450/7455 G4 7300-9600 upgrade card and make a completely Over powered 7448 based 9600 LOL)
Click to expand...
Good idea! my iMac G3 500MHz with 750CX want this interposer board!!!!!!!
 
Not to boost an older thread, but i would be interested to see what the most G4 you could stuff into a Pismo would be. I'm about as dumb as it comes with this stuff, but am I reading that there could be a possibility of a 7448 G4 in a pismo? Cooling issues aside, of course.
 
I'd love to see a 7447 on a 7400 ZIF daughtercard (Sonnet, Yikes) for my G3 All-in-One. The Sonnet 1GHz G4 ZIF upgrades are unobtanium.
 
ried said:
I'd love to see a 7447 on a 7400 ZIF daughtercard (Sonnet, Yikes) for my G3 All-in-One. The Sonnet 1GHz G4 ZIF upgrades are unobtanium.
Click to expand...
The Sonnet 1GHz ziff cards use external power, would it be better to go for a 750fx - you lose Altivec, but they are lower power and as fast for non-altivec stuff?

@Siliconinsider was previously working on something like the Powerlogix card, but I think he hit some issues sadly. Not sure what the current project status is :)
 
Phipli said:
The Sonnet 1GHz ziff cards use external power...
Click to expand...
That's a really good point. What's the power limit of a ZIF socket without additional external power? The 7447 designs have mobile applications, so my assumption is that they're relatively power efficient - but they may still use significantly more power than the G3's ZIF socket could deliver.
 
1GHz 750GX has a typical power draw of 8.3W @ 1GHz.
1GHz 7447A has a typical power draw of 16W @ 1GHz
533MHz 7410 has a typical power draw of 5.3W @ 500MHz
I am also curious what (all the variants of) a ZIF socket will deliver. I would be worried about any G4 other than a 7410.
Not sure what the power draw of the backside cache chips are, but I think it would be relevant.
 
I wonder if in a situation like a pismo, one could tap an extra 5v from the hard drive power supply or something for a 7447. I have a 7410 powered pismo and ive been brainstorming a better cooling solution that would fit into the HDD bay after I swap to a mini-SSD
 
herd said:
The main application I can see would be to install faster 7447 chips onto these boards for use in the Cube
Click to expand...

I guess I never followed up on this thread. In case any Cube enthusiasts care, the chip swaps I mentioned work fine. A 7447 at 1.2GHz uses roughly the same peak power as the stock Cube CPU. I think 1.4GHz is still conservative enough to use the stock VRM, but fan(s) should be added. Anyway, FYI.


cube7447b.jpg
 
I’m a Cube enthusiast! I’ve just discovered this thread. I’m very much interested!

So, how one does such a CPU swap? I’m guessing you need specialized soldering equipment?
 
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