I'm planing on getting a 32Gb 6-core, but avoiding the Apple Ram tax by buying it with as little Tam as possible, ditching the stock Ram and buying more from a third party, so I need to understand what's going on with nMP Ram. Do we have definitive 'I've got one and tried it and it works' answers for these questions? 1) If you build to order a 4 core with exactly the same spec as a 6-core, do you get exactly the same machine as if you ordered a 6? I know this sounds pointless at first glance, but it would unlock the option of a 12Gb 6-core, which Apple won't let you have if you start with the 6-core spec. This would save me money and meant I would be throwing away less Ram. 2) Is there a speed penalty for not filling all the ram sockets? I could get my 32Gb as 4x8 and fill all the slots, or as 2x16 with room to buy another two and expand to 64 later. 3) What's the deal with the 64Gb using different Ram? Is this stuff any faster or slower? 4) I know you can't mix registered and unbuffered, but does this really prevent me ordering a 12Gb machine, taking out 1 of the three sticks and putting in two 16s for a total of 40Gb in the future when 32Gb unbuffered sticks are available? 5) How about buying a 12, throwing out 1 stick and adding two 8s for a total of 24?