General folding hardware questions....

[Perineum]

1) When adding a second GPU to your folding machine, would 2 Nvidia cards fold in a motherboard designed for Crossfire? I would assume yes it would as there is no SLI or Crossfire happening, but....

2) At what PCI-E speeds can the second or third slot be before it severely impacts folding? Would x4, x8, x16 all fold at the same speed as there may not be much continual data flow? IE: it might take a bit longer to load the protein into video card RAM but after that it folds at normal full speed?

3) Would the system dedicated to folding run better under Windows XP 32 bit, Vista 32/64 bit or even a linux distro?

More questions to follow, I'm sure...

[Dr_BenD_over]

1. Yes
2. I've folded from a x4 slot with a 3870 and it was just about as fast as the other 3870 in the x16 slot
3. I'd have to go with Vista for GPU, and run the VMWARE folding client for the CPU.

[3.0charlie]

I agree with the Dr.'s answer, and would like to add to definitely use nVidia cards for the GPU folding.

[Dead Things]

Two things...

2) Depends on the GPU. Anything 9/8800GT and lower can run at full speed in a 1x slot. Anything over that needs a minimum 4x slot. But even an overclocked GTX295 can fold at full speed in a 4x slot.

3) The best overall OS for folding is XP64, IMO. The way XP manages the GPU client's affinity and cycle allocation with the 180-and-newer Nvidia drivers is better than Vista (i.e., essentially zero CPU overhead), which frees up cycles for running a VM SMP client. The reason why 64-bit is better is because if running a pair of VM's on a quad, you'll need the extra available addressing space. If running a 32-bit OS with say a pair of 9800GX2's, you'll be left with only about 1.8GB of available addresses, even with 4GB installed, and that's not enough to run 2xVM's plus keep your system operationally stable.

[Perineum]

Thanks everyone for your helpful and valuable input. Nice to see that someone can tap into other members knowledge without getting a "RTFM" or something similar.

[dhoshaw]

Windows 7 RC x64 runs the VM clients very well; I'm getting 6K+ PPD on my Q9550.