2 graphics cards = not booting

[cnrtechhead]

System specs:

 

10.6.2 Retail (myHack install)

Mobo: Foxconn G31 MXP-K

Gfx 1: 7600GT PCIe

Gfx 2: 8400GS PCI

 

Both cards boot fine by themselves with full QE/CI and res change, using only GraphicsEnabler in boot.plist, but when I try booting with both installed the system hangs, sometimes on "DSMOS has arrived," and sometimes on "acpi_smc_platformplugin." When I don't boot with "-v" it kernel panics.

 

I've tried switching "init display first" in the BIOS to PCI from PCIe but that doesn't help.

 

Any idea what is causing this and how to fix it?

[cnrtechhead]

Update:

 

I ditched the Foxconn board and the 8400GS. Bought an XFX 680i LT SLI board.

 

I'm now attempting to get the 7600GT 256MB DVI/DVI PCIe and and 7300GT 256MB DVI/VGA PCIe working. Both cards work fine by themselves in both slots.

 

With no enablers/injectors/strings at all, I can boot to mirrored, unaccelerated output on the LCDs connected to the card in the top slot. Both cards appear in System Profiler with basic info.

 

GraphicsEnabler=yes doesn't work at all. Unaccelerated output with one card in and KP/hang in -v with both cards in.

 

A (supposedly modified for two cards) NVinject gets me QE/CI/dual display with one card installed but hangs at boot (after detecting both cards!) with both installed.

 

I have my PCI Roots, (0x1)/Pci(0x3,0x0)/Pci(0x0,0x0) for the 7600GT in the top slot and (0x1)/Pci(0x18,0x0)/Pci(0x0,0x0) for the 7300GT in the bottom slot.

 

I attempted to make EFI strings, but I was stuck doing it in Snow because the only leopard machine I have is a PowerBook G4 that errors out when trying to use osx86tools. EFI strings gave hang at boot with both cards and a output quit right before the login window with a single card.

 

Any help is appreciated. (Especially on the EFI strings. All the info you should need to make the string should be here.)