Oldnewby has basically now got it running. Thermals look fine to me, he seems to be happy.
WOW! Thanks a lot everyone.
Some of you were concerned that perhaps the cooling solution was insufficient so I've posted some temp results here.
Cygnus X1 has been running for a few days now and no problems have been evident. All the fans have had their speed reduced so it's very quiet, the slot loader works well but you have to be ready to catch the disc when ejecting.
I've posted links to screenshots of the temp tests for those that are interested but the details are thus; at stock speed (2.4Ghz) at idle CPU is ~30C, Running several programs including transcoding an AVI file, extracting a large RAR file, watching a video, downloading a torrent, firefox with several tabs open etc, the temp was around 40C and motherboard temp varied between 25C~30C. There was no combination of ordinary programs that could take the CPU to 100%.
Bumping up the CPU to 3Ghz gave an idle temp slightly higher at ~34C and running the same combination of programs resulted in ~45C. So it will be left at 3Ghz. I wanted to see the temps for the CPU at 100%, so two instances of Orthos were run and the result here is ~55C for the CPU. So all those temps are fine for everyday running. Ambient temp during all this was 26C.
I never actually run that many programs at once so everyday running should see a CPU temp of around 34C at 25C ambient, and that's fine. I also don't play games so the GPU temp at 52C odd is OK as well.
Here's some pic's because, well, just because.
I like this one the best.