iMac7,1 Processor Upgrade Success!

[iMouse]

Not sure if anyone has attempted this sort of upgrade, but I thought I'd report that I was able to upgrade my 20" iMac7,1 (Original aluminum model) with a faster Merom-class processor.

Stock: Intel Core 2 Duo T7700 @ 2.4GHz (SLAF7)
Upgrade: Intel Core 2 Extreme X7900 @ 2.8GHz (SLA33)

I figured that this would likely work as Apple sold a 24" that year with the Core 2 Extreme X7900 as an option. Just so you know, it detects it in Mac OS X as a Core 2 Duo @ 2.8GHz and not an Extreme. Not sure if 10.6.8 and the 24" model detects it as a Core 2 Extreme or Core 2 Duo either.

I'm including screenshots from Windows Experience Index scores to give you an idea of the boost in performance both in the processor and the RAM. I would have rather used Geekbench in Mac OS X, but their benchmark list is throwing a 500 error at the moment.

FYI. I picked this processor up from a seller on E-bay for $80 + free ship.

 

[bushidounohana]

Nice work!

I've often toyed with the notion of trying this, though I've never done a CPU swap before. With it being so cheap, I could upgrade the hard drive and CPU in one swoop ... what's the degree of difficulty on changing out the CPU (outside of tearing the iMac down, of course)?

 

[iMouse]

I've often toyed with the notion of trying this, though I've never done a CPU swap before. With it being so cheap, I could upgrade the hard drive and CPU in one swoop ... what's the degree of difficulty on changing out the CPU (outside of tearing the iMac down, of course)?

Changing out the CPU is rather easy...very similar to how any laptop is set up. You'll have to remove the "void" warranty sticker from the underside heat sink bracket and take out the 4 torx screws. You'll also want to take the screw out of the end of the heat sink where the fins are. This allows the whole heat sink and heat pipe assembly to separate. (The GPU and CPU heat pipes are screwed to the same bracket).

Ought to be a really nice upgrade to those with the Core 2 2.0. Makes me wonder if the Radeon HD 2400 is replaceable with a Radeon HD 2600. The video card is on a standard MXM II slot, but you'd have to ensure that the heat plate lined up with the GPU die. I've been investigating the 8800GS MXM card as a replacement, but I believe the GPU die is on the opposite end of the card. :-(

I also coated the CPU die with a thin coat of Arctic Silver. Idle temps are 99F - 102F and load temps are about 135F - 145F. These temps are consistent with the Core 2 2.4 which ran about 97F - 99F idle and 132F - 145F load.

 

[bushidounohana]

Thanks for the insights! I'd be interested in hearing if you happen to have any success with the graphics card.

 

[anbranco]

Well done. I might do it myself. From whom did you buy it from?
Cheers.

 

[iMouse]

Well done. I might do it myself. From whom did you buy it from?
Cheers.

http://cgi.ebay.com/Intel-Core-2-Ex...818?pt=CPUs&hash=item3368830fca#ht_500wt_1156

e-Bay user ID is: eileenmckinley

The processors are seller refurbished, but the one I received was in perfect condition. Processor die was as shiny and polished as if I would have bought it new.

A lot of these high-end processors show color banding on the die due to OEMs slapping them into enclosures that can't handle the required heat dissipation. The heat leaves a rainbow band on the die. This one was perfect.

 

[anbranco]

Thanks. Well, this guy only ships to the USA and since I'm in Germany, I thought I might try another dealer that ships internationally.
I hope the chip is in good shape.

Once it arrives, I will give it a shoot!

Any luck with the graphics card?