It was not my intent to infer the Windows message loop would cause the loss in performance. While it eats away at the CPU cycles, the real loss is due to the CCC/MOM executables continuously poking the video card which inhibits data transfers.
The amount of loss will vary, based on what is running and how it is using the video card. Standard benchmarks are worthless for this. Anything from 0% to 10% can be expected.
I expect you to not find any loss, whatsoever. It will not surprise me. Leave them running, if you want. It does not hurt to kill them and it might just help if they are not running. No downsides.