CUDA Driver version and runtime version

Hi, I have a question about compability in CUDA.
Does the Driver version and the runtime version be the same? I have driver version 6.0 and runtime version 5.5.

All the calculations in my kernel function return NAN and says that thread 0 fails… I’ve been for weeks in search for the problem, so now I am checking the hardware

The driver version and runtime version do not have to be the same.
In general, the driver version should be greater than or equal to the runtime version.
If there is an unacceptable mismatch (e.g. runtime version newer than driver version) you should get a cuda API error, something like “driver version insufficient for runtime version”.

If your calculations are returning NAN, I would start by doing proper cuda error checking on all cuda API calls and all kernel calls. If you have identified a kernel unspecified launch failure, run your code with cuda-memcheck to get additional information about why that kernel is failing.

Thanks for the help, I’ll try that.