I am about to buy a 12 core mac pro and was going to buy 24 or 32 gb's but am by sure whether to do 8 gb sticks or less. Aldo curious if i can do x3 8 gb sticks or if they have to still be in pairs distributed on both sides?!
My 12 core is on order, shipped today. I've ordered 32 GB of RAM (8 x 4GB) and will let you know whether 24 or 32 is better.
The 12 core uses a Nehalem processor, the the memory controllers on these have 3 gates which pass data in and out of RAM, hence the memory is optimized using multiples of 3 RAM chips.
However, the benchmarks I seen show only a 5% drop in memory performance when multiples of 4 chips are used. I'm much more interested in loading larger files and having longer RAM previews than I am in a 5% gain in memory speed.
These Mac Pro's will support 8 GB chips but the cost of 3 x 8 GB was higher than the 32 I bought. I hope 32 will keep me happy for the next 2 or 3 years.