The GT 620 and 620M are included in the table of CUDA-compatible GPUs,
https://developer.nvidia.com/cuda-gpus
Basic first steps:
1. (Re)install the most recent NVIDIA drivers
2. (Re)install the most recent CUDALink paclet
3. Restart Mathematica
4. Restart the computer
The best reference for information on CUDA-compatible drivers is at
http://www.nvidia.com/object/cuda_learn_products.html
The CUDALink paclet can be updated, if needed, by evaluating
CUDAResourcesInstall[]
It sounds like you found the setup information in the CUDALink
documentation, but for completeness I will include the URL here,
http://reference.wolfram.com/mathematica/CUDALink/tutorial/Setup.html
If none of that gets your CUDALink working, please send the following diagnostic information to support@wolfram.com:
- the output from evaluating
SystemInformation[]
in Mathematica. (A Mathematica notebook with the output is the preferred format.)
- the output from running systeminfo in a command-prompt window
(via Start - Programs - Accessories, or Start - Run - cmd.exe)
Commands for selecting and copying text in the command-prompt window are in the menu
that appears when you click the little ikon in the upper-left corner of the window.
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