I've ordered some NF4 SLI chipsets. Very tempted to swap out the current NF4 SLI.

Just a little update. I tried Windows 7, same problem. Recapped the entire board (well almost). It made no change. I then performed the NF4 SLI mod (turns the chipset from a Ultra to SLI with a single resistor). I’m now able to run a single PCI-E card at x8 with 0% CPU usage. If I add a second PCI-E card, CPU jumps to 100% again.

Next step is to replace the NF4 chipset which is currently a NF4 SLI revision A3 (modded Ultra) with a NF4 SLI revision A4. Nvidia fixed some bugs with revision A3 in revision A4. Apparently A4 overclocks better.

zuldan wrote on 2026-05-18, 07:54:

Just a little update. I tried Windows 7, same problem. Recapped the entire board (well almost). It made no change. I then performed the NF4 SLI mod (turns the chipset from a Ultra to SLI with a single resistor). I’m now able to run a single PCI-E card at x8 with 0% CPU usage. If I add a second PCI-E card, CPU jumps to 100% again.

Next step is to replace the NF4 chipset which is currently a NF4 SLI revision A3 (modded Ultra) with a NF4 SLI revision A4. Nvidia fixed some bugs with revision A3 in revision A4. Apparently A4 overclocks better.

So lane pair 0-7 is fine, and 8-15 has an issue. Nice find!