Gaz, draklava is correct - multithreading is a function of the operating system. It is a process for passing process instructions to the cpu. But multi-threading, by itself will have no real effect in decreasing in your rendering time. For the two machines you are describing above, only the faster CPU and the faster bus speed will have an effect on rendering times. These should decrease your rendering time by approximately 30-34% percent, however. the amount of RAM really doesn't have any effect on rendering (only the CPU and bus speeds), but it will significantly affect your ability to model and place objects in your scenes. More RAM is a major help here, too. There are only 2 ways to speed up rendering in Vue - two cpu's (or more via linked machines and rendercow) or a faster processor. OF the two, more CPUs offer the most speed gain. A dual processor motherboard with 2 Pentium III 800 cpu's still outperforms a single Pentium 4 2.x cpu, but only in rendering. There are still a lot of those dual 800's widely available - for cheap prices. For all those thinking of a renderfarm (two linked PCs), this is most economically efficient way to get a major gain in rendering.