Will not render HD

FSMCDesigns

I just started having an really odd issue, I cannot get any figure at subd level 2 or more to render. It will render fine in iray interactive, but in a seperate render window I just get the checkerboard and no image. This just started as I have had no issues prior to yesterday with this even though I only have a 4 gig GPU.

I did some testing, loaded default GF8, tested interactive renderer with only the CPU and then with only the GPU, both worked great and as normal. The I tried a normal render in the seperate window with both GPU and CPU each and both times rendered fine. Then I load a scene with a warrior type GF8 at subd 2 and an 8K HDRI and it rendered fine in the iray interactive preview, but when i started a regular reender window I just got the checkerboard and the image never appeared

looking at the log I assumed their is an issue with my card since it says this

2019-02-16 20:55:35.555 Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info : Initializing local rendering.
2019-02-16 20:55:35.555 WARNING: dzneuraymgr.cpp(307): Iray ERROR - module:category(IRAY:RENDER):   1.0   IRAY   rend error: CUDA device 0 (GeForce GTX 960): unspecified launch failure (while allocating host mapped memory buffer)
2019-02-16 20:55:35.555 WARNING: dzneuraymgr.cpp(307): Iray ERROR - module:category(IRAY:RENDER):   1.0   IRAY   rend error: CUDA device 0 (GeForce GTX 960): device cannot be used as it does not support mapped memory (canMapHostMemory)
2019-02-16 20:55:35.555 WARNING: dzneuraymgr.cpp(307): Iray WARNING - module:category(IRAY:RENDER):   1.0   IRAY   rend warn : All available GPUs failed.
2019-02-16 20:55:35.555 Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info : Falling back to CPU rendering.
2019-02-16 20:55:35.555 WARNING: dzneuraymgr.cpp(307): Iray ERROR - module:category(IRAY:RENDER):   1.0   IRAY   rend error: CUDA device 0 (GeForce GTX 960): Device initialization failed, will not be used
2019-02-16 20:55:35.555 Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info : Rendering with 0 device(s):

But I can render smaller scenes with GPU only and no issues which I would think would be an issue if there was an issue with the card.

I took the subd level back down to 1 and the scene rendered fine with the GPU only and no errors in the log file

2019-02-16 21:16:18.369 Iray INFO - module:category(IRAY:RENDER):   1.0   IRAY   rend info : CUDA device 0 (GeForce GTX 960):      119 iterations, 23.128s init, 13.940s render

I have deferred updates on so I haven't had any updates installed and I did try 2 different sets of older drivers which didn't help just in case.

Any ideas?