Folding Forum

Is the following a good guideline for who wish to upgrade a GPU for folding? any better info is welcome.

Older then HD5xxx may run out of WU in not too far future.
If you have WindowsXP there maybe some driver support issues for HD7xxx. You must stay with 11.12 at the newest. No such a limit for Vista or Seven.
Better to have at least 400 compute units. (maybe a multiple of 400 ?).
And after all, the more the better but remember the electric bill.

Not sure where the 400 comes from, but NV cards have issues with drivers as well. Latest 301.xx diver seems to work the best.

Yes, is not meant to underline a problem but to avoid problems, as a sample is easy to find an hd4xxx but better to add a little money and get a hd5xxx or newer to have a good longer lasting folding GPU. While the hd4xxx is still completely usable for other uses.
About NV vs AMD-ATI in my experience I had less stability problems with AMD-ATI then NV.
About the 400 stream processor I remember a note in the forum (can't find it now) about some newer projects with OpenCL needing that minimal amount, maybe I'm just wrong on this.

Having more shaders is always bettert than having fewer but there's no magic number. I fold on GPUs that have many shaders and others that only have a few. In my case, I'm not making a purchasing decision, I'm folding with the hardware I have.