GPU issues 9,1 imac 24"

LKJ


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I replaced the NVIDIA 130GT w/ a 4850 AMD Radeon card from a 27" imac, same year (late 2009). Computer boots, all 4 LEDs go on, computer accessible from remote screensharing on the LAN so is obviously up and running. No picture on the screen (backlighting working).

I think it's an EFI/firmware problem w/ the new card. Any ideas as to a work-around? Edit the BIOS in the GPU to match the 24 inch screen or the Logic board ID? Thoughts? Thanks!
 

chscag

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You can't just swap the video card in your iMac with a card from another model and especially one with a different chipset and expect it to work.

I think it's an EFI/firmware problem w/ the new card. Any ideas as to a work-around? Edit the BIOS in the GPU to match the 24 inch screen or the Logic board ID? Thoughts? Thanks!

That may be part of the problem but it's likely because there are no drivers (supporting kexts) for the AMD. There is no BIOS in the GPU to edit.
 

pigoo3

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Interesting experiment...would have been realy neat if it had worked (especially since both iMacs had to have socketed gpu's).:)

Firstly...to be 100% accurate:

- the "recipient" 24" iMac is an "Early 2009" model
- the "donor" 27" iMac is a "Late 2009" model

So they are not the exact same model generation. The:

- Early 2009 24" iMac is a (9,1)
- Late 2009 27" iMac is an (11,1)

Plus...there were no "Early 2009" 27" iMacs.

Now interestingly (after some research)...the Early 2009 24" iMac's (via custom configuration) could have had a Radeon 4850 graphic hardware in it (just like the Late 2009 27" iMac).

So I'm thinking (similar to chscag)...even though both computers could have had a Radeon 4850 video card installed in them...there is probably some sort of firmware difference (due to different iMac generation).

One BIG difference between these two computers is...the 24" iMac had a core 2 duo cpu...and the 27" iMac had a quad-core i5 cpu. So these two computers certainly had different firmware.

- Nick
 
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LKJ


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Ah well, figured it was way too easy. I'm used to Mac's "Just Working"....I could hot-rod my old G4 and PPC pretty easily and was hoping if the GPU designation matched it would be a plug and play, didn't consider the quad core cpu.:Oops:....GT 130 back in and just putting up w/ freezes when it gets too hot until I get so irritated I junk the whole thing. Not quite like hot-rodding my Roadrunner. Thanks!:D
 

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