CUDA Runtime Error 4 - showing up after update from CUDA 3.2 to CUDA4

I have recently tried to update my system from CUDA 3.2 to CUDA 4.0

This seems to not be a very smooth update. First of all, a lot of the SDK examples fail now. matrixMul and the FFT problems and such all come back saying the errors were too big, so they give a fail.

Code that I have written also seems to have some problems. I had to track down some err开发者_如何转开发ors caused by NaN that I never had before, and I am getting occaisional kernel launch failures now too. Usually it says

cudaSafeCall() Runtime API error 4: unspecified launch failure.

or

cutilCheckMsg() CUTIL CUDA error : fftshift() execution failed
 : (4) unspecified launch failure.

(fftshift being my function that has never failed before, in 3.2)

Do I perhaps have something misconfigured here?

I have tried using the 270 driver that was released with 4.0 for development, after having downgraded from the latest driver that I thoguht was maybe causing problems.

Thanks for any tips

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I'm going to assume (since you didn't specify) that you are running Windows(7) and are trying to use 3.2 SDK samples with nvcc 3.2 compiler but with 4.0 capable drivers. If so, you should know that version 4.0 has a major revision in regards memory addressing (namely Unified memory addressing on 64-bit systems) in addition to a whole bunch of other features.

What you want is to uninstall CUDA 3.2 driver, SDK and Toolkit (purge them for good). Then download and install all the 4.0 versions of the above. The new SDK samples should work, provided everything is installed correctly.