Transplanting Video Cards (Late '09 iMac)

[iindigo]

Curious if anybody has tried this...

As many of us know, iMacs have been using MXM video cards for quite a while now. While stock MXM cards don't seem to work in the iMac's MXM slot, what about buying a card from a newer model iMac?

For instance, I own a late 2009 27" iMac with a Radeon 4850 512MB. Would it be possible to buy the Radeon 5750 1GB service part from the newest revision and swap it out for the 4850? The slot and card form factor look the same to me.

Links to the cards in question:
Radeon 4850 512MB (iMac Version)
Radeon 5750 1GB (iMac Version)

 

[Ca$hflow]

This is an excellent question. Does anyone know?

 

[OliverOSX93]

Im doubtful someone has tried this before, looks like you get to be a pioneer

 

[Rodus]

Dont think anyone has done it but as the card will have the correct Mac ROM and is supported in OS X it probably will work. However the high cost for a pretty small performance boost make it not really worthwhile.

 

[iindigo]

I was under the impression that the 5750 was a fairly significant upgrade over the 4850. Is this not the case?

 

[EntropyQ3]

I was under the impression that the 5750 was a fairly significant upgrade over the 4850. Is this not the case?

It's not. The 4850 has more shader processors (800) than the 5750 (720) and has a wider bus (256-bit vs 128-bit). The 5750 on the other hand has higher clocks than the mobility 4850 in the iMac, and has GDDR5 vs. GDDR3 on the 4850, neatly making up and more for both the lacking shader processors and the narrower bus. Barefeats have benchmarks for you, but they simply confirm that the 5750 iMac is 10-20% faster than the 4850 one.
Irrelevant, basically.

 

[iSayuSay]

I was under the impression that the 5750 was a fairly significant upgrade over the 4850. Is this not the case?

ATI's numbering is quite messed up recently. Radeon 5xxx doesn't always mean faster than 4xxx

Even from the same series. Take example for 6750 is actually slower than 5750, that's kinda confusing

 

[Rodus]

Plus the only difference between the 4850 mobility and desktop cards are the clock and RAM speed, if you are gaming under Windows then use MSI afterburner to overclock the card and it'll match the 5750.