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theodor12

macrumors newbie
Original poster
Dec 2, 2020
20
2
Hi community,
so I have my old PowerMac G5 Late 2005 with 2,5 ghz dual cpu single Delphi pump laying around, but it’s broken.
It immediately overheats, which makes me suspect the pump. That LCS is just unusable for me and I am not experienced enough to bother fixing it.
So I searched on eBay and found a pair of air cooled PowerPC (probably single core) processors clocked at 1,8 ghz.

Now, here is my plan.
I thought that I could try my old cpu cards with the new air cooled heatsink. And if that heatsink wouldn’t be able to cool the two core beasts, then I would use the new 1,8 ghz cpus and their appropriate coolers.

Do you guys and girls think that one of these options could “work”?
 

Macbookprodude

Suspended
Jan 1, 2018
3,306
898
I don't think it will work. The logic boards for 1.8 and 2.5 quads are quite different. The 1.8 comes from a different model G5 and I don't think the Quad's logicboard can be downclocked from 2.5 to 1.8. You can try it, but I don't think it will work. I am surprised the single pump broke on you. I thought between the dual pump and single, the single was more reliable. I have a G5 Quad with single pump in the box and not using it. I am considering getting rid of it as its useless to me - No room on my desk to it.
 

theodor12

macrumors newbie
Original poster
Dec 2, 2020
20
2
I don't think it will work. The logic boards for 1.8 and 2.5 quads are quite different. The 1.8 comes from a different model G5 and I don't think the Quad's logicboard can be downclocked from 2.5 to 1.8. You can try it, but I don't think it will work. I am surprised the single pump broke on you. I thought between the dual pump and single, the single was more reliable. I have a G5 Quad with single pump in the box and not using it. I am considering getting rid of it as its useless to me - No room on my desk to it.
Well, I am not entirely sure that it’s broken. When I boot it, it chimes and then lasts for like 5 seconds before the “OVERTEMP” and “CHECKSTOP” LEDs turn on. When I touch the pipes, they are quite hot near the processors, but absolutely cold near their end.
 

theodor12

macrumors newbie
Original poster
Dec 2, 2020
20
2
Today, I found these CPUs. They claim to be compatible with Late 2005 G5s, which is my case.
I should rather buy these than the old ones I found, right?
 

ftalbot

macrumors member
Nov 25, 2012
46
28
Québec City
Today, I found these CPUs. They claim to be compatible with Late 2005 G5s, which is my case.
I should rather buy these than the old ones I found, right?
Which CPUs?

As far as I know, you will need late 2005 dual core CPUs. They come at 2.0, 2.3 or 2.5 ghz speed. The heatsinks from the 2.0 and 2.3 variants are too large to fit a dual processors setup (unless you do some serious modification). Theoretically, you could turn your quad 2.5 into a dual 2.0 or 2.3 (single processor / dual core) or repair the liquid cooling and make it a quad 2.0 / 2.3 (dual processors / quad core).
 
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