You literally go onto DOCP/XMP and enable it and choose a profile with speed. It’s very easy. Although there is a slight chance, it will be unstable - in which case, clock the speed downMy new PC arrived yesterday and is AWESOME! And that's even with the RAM running at just 2666MHz, so today I'll do some research about tweaking that DOCP - from a quick search it looks fairly straightforward, but I may be back here asking for more advice!
Interestingly, an After Effects project I've been working on for the past couple of weeks on my old PC without issue, caused the new PC to crash while using hardware (GPU) rendering. Switching to CPU rendering solved the issue, but I didn't buy an RTX3090 to not use its full potential!