Well, so far so good. The new bits arrived at around 12.30 and despite stopping for lunch by 3pm I was playing new material into AA. installation was reasonably painless, though the second IDE port on the Asus MB is about as far away from my DVD writers as it's possible to get, and without a longer cable than that supplied I've only managed to reach one of them in my average-size tower case. I also had to disable the SATA/RAID boot rom, despite a strong warning in the manual against it, to allow the system to boot up with the Plextor writer connected - the only point where there was any head-scratching on my part.
There seem to be an excess of features I've not bothered with - remote control, for example - but once I'd stopped fighting with XP wanting to install new hardware and Plextools trying to take over the DVD writer I managed to get the two driver discs in and installed painlessly. I'm sure I've got a GB more memory than XP will use, so what happens to that I don't know. As for my four cores, well three of them are currently idle (during mono 32-bit record) and one is rather snootily lowering itself to providing about 3 percent of its available juice for this menial task!
I did run a quick NR using Izotope's new RX suite, which at its most extreme setting is desperately power hungry, and it does seem to bring thing to somewhere within the realms of the practical - in other words hugely faster than before, if still nowhere near real time. What I didn't check was whether it was using all four cores at this point - if not I have no idea whether I can persuade it to. Quad-core I may have, but about it I know practically nothing...