well, I have moved my graphics cards about, installed the RME PCIe card to a different slot and still the same.
I notice that there’s no noise through the headphones straight out of my Multiface 2, so I guess I had better try some better quality cabling to my yamaha monitors.
Apart from the new PC, all my hardware is exactly the same, in the same place etc, so bit of an odd one.
I had a similar problem after building my current DAW. Switching to short, balanced cables for my monitors solved the problem. That was with a PCI Audiophile 192 M-Audio card (ditched it due to crappy 64-bit Windows 7 drivers and unsolvable random pops). Definitely something worth trying, I think.
New cables is a good idea if the old ones are unbalanced and/or poor quality ones. But before spending any money you can also try to rearrange your cables in a way which analog audio cables:
are as away far as possible from your computer/mouse/display
do not run parallel with any other cables connected to your computer