After working a while now with both the Dual 2.0 GHz and and the Dual 2.5 GHz, I have to conclude that the Dual 2.5 GHz is seriously getting on my nerves. When the machine is idling, the noise level is OK, but when the load goes up, maybe because a few tabbed browser windows are showing animations, the revving "blowdryer" noises are just too damn annonying to offset the 1 GHz speed advantage.