Could you have by accident installed 32bit windows? I know you said it's x64 but it sounds like you're pressing that 4gb limit (~3.25gb addressable)
I can confirm it is indeed x64 via the Control Panel's basic system information. I have the same distro installed on two other rigs, one of which is an Intel Bad Axe 2 seating 1 390x, 1 290x & 1 290 w/ 2 x 1 GB + 2 x 2GB where all 6GB are properly allocated and the other from vague recollection is an Asus P5b also on socket 775 with 2 x 2GB where only 3.25GB is usable as indicated in the motherboard's manual.
fo00ok
I have a very similar PC - s.775, 4GB RAm, Win7, 3.25GB recognized with latest bios and 290 inside.
It works flawlessly with Virtual memory set to static 16GB size and all Genoil/Claymore versions
Ethminer works just fine as well as Claymore's v1.2. I just set a single 16GB pagefile and tried launching v4.1 and it returned the following error: GPU 0, OpenCL error -4 - cannot create DAG.
@Claymore
I uploaded my log and would be very grateful if you can take a quick glance at it.
https://dropfile.to/aCSRy1dI'm mining with 775 CPU's and boards here..
win 7 64bit, 4GB ram, 80gb HDD , Xeon 3220 (Q6600)
I'm mining alright here, currently on v3.2 ...haven't tested the V4.0 (the no DAG version)
I have a pentiumD, a pentium 4 HT, and core2duo E8400 that I decomissioned for mining...these very old CPUs compared to X3220 are affecting hashrate..
and one of the best advantages of v4 is the minimized cpu usage.