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Best CPU for a MDD G4 without overheating

Unknown_K

68040
I got a different board and CPU for my MDD (Dual 1Ghz 167 FSB) and was wondering if the 1.25ghz of 1.4ghz DP is worth getting since I hear they overheat. My old CPU was 867 DP and 133 FSB. Didn't the faster speed chips have a solid copper heatsink instead of the aluminum ones?

 
Only the 1.42 ghz came with a copper heat sink.

A dual 125 or 1.42 will be faster as not only are the processors faster, they also have a larger cache. If you get a 1.42 then it might be a good idea to score one with the heat sink.

When you installed the dual 1ghz, I hope you altered the motherboards bus speed resistors. If not then your 1ghz processors are likely running very slowly

 
The dual 1ghz came with the correct motherboard so no mods needed (one of the reasons I got that combo was so I didn't have to mod my old board).

P.S. there are 2 kinds of Al heatsinks from the looks of it, one is extruded and the other looks like it was made from sheet material pressed together?

 
The extruded one is the earlier one, later they switched to the sheet metal one. The base is a solid piece of aluminum and it looks like the fins are glued on.

I’ve heard that the later one was better for cooling but I’ve never gone through the trouble to do any tests. I’ve used the original in a dual 1.25 overclocked to 1.33 ghz without overheating problems and I really pushed that one. Once I was curious to see how long it would take to render a particular 1080P video clip. It ran full speed for about 2 days before it finished.

 
Dual 1.33 GHz G4 CPU cards are also commonly available for the MDD. They come from the G4 Xserver. They're easier to find, usually, than the dual 1.42 GHz cards.

One Ebay seller has had new ones (Apple Service Parts) for sale for $75 + shipping for a couple of years. But it doesn't include a heat sink, which could be an issue if you're going from single CPU to dual CPU.

I've often toyed with the idea of trying to mount some of the LGA775 heat sinks in the MDD on the dual G4s. The trick is to find one with a long enough base to cover both CPUs (some have it) and which isn't too tall to fit in the space. Also, oriented so that the fan is blowing through the fins and not against the fins when the heat sink is covering both CPUs would be good.

Of course the other trick would be to machine some kind of base to mount on the MDD screw holes and provide the proper mounting holes for the LGA775 heat sink.

 
The aluminum heat sinks on the single and dual are identical.

One Ebay seller has had new ones (Apple Service Parts) for sale for $75 + shipping for a couple of years. But it doesn't include a heat sink, which could be an issue if you're going from single CPU to dual CPU.
 
Going back to the hacking in an LGA775 heat sink, this one has the needed attributes, if one could create a mounting adapter on which to screw it in securely.

XP-90

XP-90c1.jpg.c232b7aaf6c363d4b816f2b9c1077700.jpg


Also, the Enzotech Ultra-X, although it's a little trickier, since the heat pipes should maybe be facing away from the case fan, and therefore the heatsink may stick too far into the middle of the case. And the height just barely clears.

259_uxfan_1199816385.jpg.2d7e4e80512067641c4817a091861b17.jpg


And the OCZ Tempest

ocz_tempest_pipes.jpg.fb8b9bbf02ec338ff0dc9b7bba406469.jpg


 
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