... the six real-world application benchmarks in SPECviewperf offer a more specific determination of performance. Five of the six programs benefited most by the AMD Phenom-II X4-965, with the Phenom-II X6-1090T trailing right behind, and only one test (Maya) craved Intel processors more than any other.
You should probably investigate how an entry-level Quadro card might benefit you --- otherwise, the more VRAM the better.
In dealing with large models and gazillions of vertices, the performance of your RAMs is critical (which is why workstations utilize ECC memory). Asus AM3 desktop motherboards support ECC --- as do the integrated memory controllers in AMD desktop processors. I would highly suggest you bite the financial bullet and step up to ECC RAMs but I understand how difficult that can be when a 4GB (2 x 2GB) kit of Crucial DDR3 1333 is $67 (or you can splurge on the 8GB (2 x 4GB) kit for $148 --- the 2x2GB kit of ECC roughly costs this amount. IIRC the 2x4GB ECC kit is around $250.