On the Adata ram, it's not the IC's it's the quality of the exterior. The heatsinks are garbage/useless white pot metal that doesn't absorb heat well. G.Skill uses real metal heatsinks.
AMD memory controllers don't handle much more than 1600 anyway, I have 2000 ram in my AMD backup rig, I've had a 945, a 550, and the currrent 555 and non of them could run the ram at 2000.
The power supply I picked out is way better quality as well, and again the 640gb hard drive isn't all about having another 140gb, it's dual platter VS the 500's single platter.
He will have no noticeable difference between the 945 and 635.
Seagate= 3 year warranty.....western digital= 5 year warranty