On APG 8x graphics cards i measured upload speeds from CPU to GPU using Pixel Buffer Objetcs (PBO) up to
for 2d textures so here one comes pretty close to 2 GB/s, the theoretical limit.
However, on PCI-Express cards like a FX3400 from NVidia the theoretical limit would be 4 GB/s, nevertheless i measured that the PBO speed is even slower here
1300 MB/s (using the latest drivers).
Does anyone have yet found a PCI-Express graphic card/system combination that comes close to 4 GB/s when uploading data from CPU to GPU?
Repeat after me: Never post “using the last drivers”, always give a version number.
People cannot try the same things you do if you don’t tell such important details.
i tried it with various drivers, e.g. starting from 61.77 up to 66.81 from the NVidia ftp side.
See? For the adventuresome there’s already a 70.41 beta floating around. Don’t know if it helps.
It would be interesting to know the performance on a GeForce 6600 GT (native PCIe). AFAIK the Quadro FX 3400 is a NV 35 GL with HSB. I delayed the purchase of a GeForce 6800 GT (AGP 8x), waiting for a PCIe nVidia card and, of course, nForce4 mobo. I’m very interested about the read-back performance of a native PCIe nVidia card.
Hey guys FYI I also noticed a performance problem with the FX3400 card, this time using glTexSubImage2D:
Hope Nvidia will fix this soon !
you are right, using glTexSubImage2D i get not more then 185 MB/s with BGRA/RGBA and 340 MB/s with Luminance8/Luminance16 format.
Also the speed differences for PBO differ greatly.
The 1300 MB/s i mentioned above are only achieved with Luminance16. With BGRA i only get 225 MB/s!