Yes I use vmprotect. Do you know a lot about it to state that it's the reason of problems with GPUs? If so, let me know more details, I will be glad to check it.
I always test both original and vmprotect versions on my systems and I never saw any differences for several months in different miners and other software I created.
For CryptoNote miner, for example, both versions don't work until I set pagefile 16GB.
If you have problems with vmprotect - miner will not start on your system at all because it does its job at starting only. If you see at least one line in console after starting - everything works properly.
The problem is in AMD drivers, they don't want to work with large memory sizes. Drivers just don't allow OpenCL app to allocate a lot of GPU memory at once. For example, 290X card has 4GB but OpenCL gives me less than 1GB at once by default. GPU_MAX_ALLOC_PERCENT variable is a solution (I can assign up to 3GB), but buggy solution as you can see. And AMD found a solution - today I tried Catalyst 14.6 and even with GPU_MAX_ALLOC_PERCENT I cannot allocate more than 1GB at once now. So they solved the problem

I have a couple of ideas about possible workaround, I hope it will help, new version will be available soon. Anyway, working with AMD OpenCL is some kind of magic which is much more unstable than vmprotect.
It would be great to have your new version soon, and hope that we will be seeing some improvements again in the hashrate...say 50%