Can someone please suggest any tool for scanning memory (RAM) of a video/graphic card? All I can find are some very old programs that do not support modern cards as they, for example do not support more than 512MB RAM (I have 3GB) or demand to change the video mode to 640x480 and my card does not support so small resolution under Windows. It can be for Windows or Linux. Please be aware I have AMD/ATI card so tools using CUDA will not work. Also, I am not interested in video benchmarking but solid memory testing.
Have you tried either MemtestCL from Stanford University's Folding@home project? If your card supports OpenCL, then you should be covered by MemtestCL. MemtestCL is supported under both Linux and Windows, while MemtestG80 (for CUDA cards) supports Linux, Windows and OS X.
Like @Gelo Mitt says, I can't recommend either one, but hope it helps somewhat.
Did you try this program -- http://mikelab.kiev.ua/index_en.php?page=PROGRAMS/vmt_en ? There are two links, at the top and at the bottom. Use the one at the top, the one at the bottom contains a floppy image, that's not what you need. In the archive there are "windows version" and an iso image in the VMTCE folder. According to the readme file if you boot from the image you won't be able to address more than 512 MB, but "windows version" should work.
I can't recommend this program since I never used it. I just happen to know of its existence.
Also if it won't work please indicate what tools you have already tried.