All GPU acceleration really does is shift some of the load from the CPU to the GPU. It's likely that, because of your overclock, you can run SVP at full speed even without GPU acceleration.
The thing is, there's a maximum that SVP will run at even if you have lots of processor head room. In order to pass that limit you would need to use custom settings in SVP, and even then that only raises the bar rather than eliminates it.
If you really want to get GPU acceleration working, I would try running DDU (LINK) and then re-installing your GPU drivers. You can also try installing the drivers for your Intel integrated GPU and selecting that in SVP (this is particularly useful if you use MadVR since you can dedicate your 970 to that).