I tested with a house fan to reduce the temperatures, and got some pretty good results. CPU temperature dropped from around 55 to 35 (running at full speed) and motherboard dropped from 40 to 30, and I did not get a slowdown at any stage during my extensive testing (played games). This tells me I need better airflow within the case, so I've ordered an Antec Super Cyclone Blower exhaust fan to mount in the expansion slots and an Antec 80mm TriCool (Green LED!) intake fan to mount on the side in place of an 'air funnel' which is currently doing absolutely nothing. They cost me a total of about $27 AUD, and both fans have three-speed settings, so I can experiment with different speeds to see how I get the best results. This should hopefully solve my problems. I'll update this thread when I've put them in.