If nvidia-smi doesn't see it, then msieve won't. Perhaps you need to reinstall the CUDA driver with the M40 installed?

[QUOTE=frmky;605578]If nvidia-smi doesn't see it, then msieve won't. Perhaps you need to reinstall the CUDA driver with the M40 installed?[/QUOTE]Reinstalled driver and CUDA in different variations and no joy. The computer says it's there, but CUDA says it isn't. I put the K20Xm back in and it sees it every time. Both are PCIEx16 v3.0.

Giving up for now. . .

ETA: Msieve compiled with 5.2, but couldn't find the cqard, as expected.

Thanks for the help.

I guess I have found my answer for the M40:[code][ 1562.849818] NVRM: This PCI I/O region assigned to your NVIDIA device is invalid:
NVRM: BAR1 is 0M @ 0x0 (PCI:0000:01:00.0)
[ 1562.849819] NVRM: The system BIOS may have misconfigured your GPU.
[ 1562.849824] nvidia: probe of 0000:01:00.0 failed with error -1
[ 1562.849839] NVRM: The NVIDIA probe routine failed for 1 device(s).
[ 1562.849840] NVRM: None of the NVIDIA devices were initialized.[/code]And, no newer BIOS updates addressing any PCI issues.

That's a BIOS issue. Google says to look for options deep in the BIOS menus like PCI Express 64-bit BAR Support, large BARs, or above 4G decoding.

[QUOTE=frmky;605610]That's a BIOS issue. Google says to look for options deep in the BIOS menus like PCI Express 64-bit BAR Support, large BARs, or above 4G decoding.[/QUOTE]Thank you for all the help with everythig. I do appreciate it, but I'm going to leave it sit for now. I did search the BIOS and all I found were two things: a Robust Graphics Booster with Auto/Fast/Turbo setting, for which there is a red message (for all three settings), "[COLOR=Red]Warning: VGA Graphics card is not guaranteed to operate normally[/COLOR]," and a PCIE frequency adjustment with a warning about setting it above 100MHz. The messages are displayed for the K20Xm as well. I guess I should consider myself lucky that one works.

Thank you, again, for all your help.