Core 2 Duo to Xeon Quad Core-now my 9800 gt is not recognized

[passoporto]

I just upgraded my cpu from a 3.16 GHz Core 2 Duo to a Xeon X5460 3.16 GHz Quad Core by doing the 771 to 775 mod. My mobo is a Gigabyte GA-P31-3GS with a paltry 2 Gigs of DDR2 SDRAM 666MHz. I'm running a dual boot system with OSX Lion 10.7.2 and Windows XP SP3. The problem I'm having is that my EVGA Geforce 9800GT 512 MB is now not recognized (At least, that's what I think is the problem). I get past the Apple logo and timer screen and when it's about to start-up all I get is black and grey screen with a few white boxes-like a test pattern. Has anybody else had this problem? I know that I'm "IN" OSX because, even though, I have to turn off the computer after this happens I still have to hold down the powerON/OFF button á la OSX.

The thing is that it boots up fine in XP with both cpu's.

(A somewhat long-winded Backstory) I first tried the new cpu with OSX 10.7.2 first and got the aforementioned test pattern screen. After several attempts with Chameleon and using various boot flags -x, -v, cpus=1, ncpi=0x2000 and no love I decided to try XP just to test. It booted to XP no problem although intially the system info showed that the processor was only operating at 2.66 GHz. Next I tried OSX again and this time I never made it to the Apple screen because of an EBios read error: Error 0x01 Block 0x02ecla8 Sectors 0. I reinstalled the Core 2 Duo cpu and got the same error! So using disc utility I repaired permissions and was finally able to boot back in to OSX with the old cpu. I thought that, perhaps, this is what I needed to do all along (just repair the permissions) so I reinstalled the Xeon, reset the Bios and was able to finally get the Xeon to run at 3.16 GHz in XP. Unfortunately, even after repairing permissions with disc utility (using the installer DVD) before booting to OSX on the HDD I still got the test pattern.

However, looking at System Info the processor IS recognized by OSX 10.7.2. as an Quad Core Intel Xeon processor and correctly shows how many cores (4) and that it is operating at 3.16 GHz. When I look at the Graphic Card info it says the following:

Type: GPU
Bus: PCIe
PCIE Lane Width: x16
VRAM: 3MB
Vendor: NVIDEA (0x10de)
Device ID: 0x0614
Revision ID : 0x00a2
Kernel Extension INFO: No kext loaded

With my Core 2 Duo installed the Graphic info is displayed correctly (even listing which monitor I'm using). Why would a kext work for the 2 Core and not a 4 Core? Do I need to install 10.7.5 updates and maybe the latest Cuda Drivers? (I installed all the latest Cuda Drivers with XP) Any help would be greatly appreciated! Thanks in advance.

 

[passoporto]

OK a little update. I upgraded to 10.7.5 and installed Cuda for Lion. Same result as before-the dreaded test pattern. The 9800 gt works perfectly with 3.16 GHz Core 2 Duo and even works with or without GraphicsEnabler. It appears that I have the correct BIOS for this card F6. And still no love. Anybody?

 

[brummymax]

I had no problems going from an dual E4300 C2D 1.8GHz to an quad E5450 XEON 3GHz on an Asus P5KPL-AM. Have you tried running windows or linux on it?

This might be unrelated but:
I did get a problem when going from an NVIDIA GT610 to an NVIDIA GT640 on the same system. Both of those cards work out of the box on 10.9.1 but the DSDT I created when running the GT610 wouldn't sit happy with the GT 640. I did not realise the DSDT was affected by the graphics card. Anyway, it booted with DSDT=null. Then I created a newly patched DSDT with the GT640 in place. Are you using a custom DSDT?