Which CUDA Toolkit version for older NVIDIA Driver

Finally Nvidia decided to add a table to the release notes in which the driver versions are determined. Here is the link from Nvidia documentation for Cuda version 10 and here is the screenshot:

Also according to Cuda installation logs in Ubuntu and another stackoverflow post CUDA toolkits require the following minimum Nvidia driver versions in Linux OS:

at least 340.00 is required for CUDA 6.5 at least 331.00 is required for CUDA 6.0 at least 319.00 is required for CUDA 5.5

I did not find an official NVIDIA document, but here is a list containing the minimum driver versions up to CUDA 6.5:

http://docs.roguewave.com/totalview/8.14.1/html/index.html#page/User_Guides/totalviewug-about-cuda.31.4.html

So for your driver version 304 this means CUDA 5 is supported.

However, there should be a newer driver (version 340.76) available which still supports your card according to NVIDIA (see "Supported Products"):

http://www.nvidia.com/Download/driverResults.aspx/81761/en-us

Using this driver you should be able to use CUDA 6.5.