Also, I tried both Radeonboost and no Radeonboost activated. Can't seem to tell a difference. Is it still needed with 10.14.6? I do confirm with either setting that VideoProc shows H264 and HEVC active whereas non-OC Mojave shows not active.
I think it depends on the card as to how much it improves anything. on the RadeonBoost thread on this forum you can see some tools you can download to run that will show whether you are technically getting any GPU improvement. I initially tried RadeonBoost, ran the tests, felt that improvements were minor and many people said on that other thread that for my card (RX580) that was to be expected. So then I turned off RadeonBoost. However later on I turned it back on and its been on ever since..I can't remember why I decided to keep it on...I think partly because that is the default of MyBootMgr and I felt like, "why not?".