about video card acceleration

[zjuer]

Hello everyone,
I want to buy a video card to accelerate abinit, my problem is (1) Is the capacity of the memory of video card important, is there a great difference between a video card with 1GB memory and that with 2GB memory? Is gtx460 proper for my purpose, or what's your recommendation, around $200? Thanks.

[pouillon]

This is not as simple as that, and you may not always get better performances with more memory, since a lot of data has to be transferred from the main memory to the GPU - and vice-versa. These transfers can become a bottleneck under some circumstances, and actually slow down the calculations.

There are in any case many criteria to take into account:

• the kind of calculations you want to perform;
• the typical size of your systems;
• the tunability of your input parameters for this kind of architecture;
• whether the GPU is connected to a screen, in which case performances might drop significantly;
• the capabilities and limitations of the implementation;
• ...

Buying a GPU only for Abinit might also be a little overkill. You probably should think about using it for other codes as well.

[zjuer]

Thank you for your enlightening suggestions.