This afternoon, I canceled my 6 core purchase from last night and went with an 8 core 2.93 GHz. Saved me ~ $1000 (when accounting for tax from Apple vs. the new vendor didn't charge tax in my state). I was on Trans Intl website and they wrote the following in regards to RAM upgrades: Upgrade Tips : Trans Internationals RAM for 8-Core Mac Pro fully complies with Apple and Intel standards. 8-core Mac Pro offers Eight slots for memory, supporting up to 32GB. DDR3 1066MHz ECC SDRAM is an advanced and reliable memory technology. ECC adds reliability by automatically correcting memory errors if they occur. More memory (RAM) increases overall performance when working with large files and memory-intensive applications such as graphics, audio, video, and scientific applications. Note: 4GB and 8GB Modules should be matching pairs from Transintl only. Yet, they sell 48gb and 64gb kits (using 8gb sticks). Doesn't that contradict their statement that it supports up to 32gb? What gives? You can upgrade to > 32gb but no performance gain? What is the sweet spot in your opinions for upgrading RAM? Thanks.