for ddr3 support you might as well say goodbye to dual core. The difference is that with dual core your system would be able to process rendering in applications that didnt require alot of workload. For example if you were rendering one thing at a time, like if you were texture rendering and THEN ecided to render lighting. With a quad core cpu, its better because it increases the amount of load that the cpu can take by having each cell process a different stream of binary. So it is very wise to go with qud core due t the fact that you will gain a much faster workspace if your looking to make high res models. As far as the ddr3 ram issue, the only processors I know of that support DDR3 as far as quad are currently the Intel Quad Duo and The AMD Phenom. The phenom is rarely new and I dont know how it fairs against graphical rendering but it should be just effective as the quad Duo, if you can find a fairly priced AM2+ board heh. The thing with these processors is that they only support certain types of ram. Like for example if you ever wanted to use DDR3 PC-6400 the only compatible cpu is the phenom on an amd setup, though I think the quad duo can run that ram speed just fine on other boards if I’m not mistaken. Now on the issue of price, for a medium end system to do fairly well graphicly, you might as well build a high end machine geared for gaming but use it for rendering, if you wanted to go high-Res that is. The reason is that for $1500 you wont gt a really good system due to the fact that RAM is the biggest issue when working with models in 3DSMAX or zbrush as you smooth more and more. So I would recommend just buying a socket am2+ board and phenom, then getting an ATI 3850, andload the board with tleast 2-4gigs of ram. You can use your hard drive you currently have and cd drives. These three components wont cost you more than $720 US. well with the ram added on let’s say the total would be close to $900. Intel setups run about the same as far as price.