I upgraded from a pair of GTX260s to a GTX470 and later an additional GTX465. When I switched from 2x 260s to 1x470+1x260 I noticed huge problems with 2D performance. Scrolling in a web page on screenX/GPU1 will absolutely kill the framerate of a video running on screenY/GPU2, VDPAU or not.
As this workstation rig is mostly used as a DEV environment for web applications, it didn't bother me terribly, but I am getting sick of living with the issues. I upgraded the second 260 to a 465 (more or less the same chip as the 470, as opposed to the newer 460s) trying to resolve what could be compatibility issues, which fixed some non-performance related issues, but I'm still stuck with crappy 2D performance.
Anyone else having these issues with Fermi cards?
2x Xeon E5520's, 7GB of RAM
NVIDIA Driver 275.09.07
MTRR seems to be a problem, but even with kernel flags (enable_mtrr_cleanup, etc) I cannot seem to resolve them. The BIOS doesn't have the option either.
reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back
reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back
reg02: base=0x0bb800000 ( 3000MB), size= 8MB, count=1: uncachable
reg03: base=0x0bc000000 ( 3008MB), size= 64MB, count=1: uncachable
reg04: base=0x100000000 ( 4096MB), size= 4096MB, count=1: write-back
reg05: base=0x200000000 ( 8192MB), size= 128MB, count=1: write-back
reg06: base=0x204000000 ( 8256MB), size= 64MB, count=1: uncachable