8GB and above memory configurations for an i7-860/P55 Mobo

[avin]

I was advised (here) that "you can easily go with the max supported 16Gb of a P55 based MOBO".

For i7-860 with no OC I understand I need 1066 DDR3 or faster, 1.5 voltage, dual channel memory. Searching newegg for 1066 or 1333 kits returns 2 x 2GB or 2 x 4GB results, where the 2 x 4GB kits are very expensive, two to four times as expensive per GB than the 2 x 2GB (say $25/GB vs $50/GB for 1066 memory, $25GB vs $100/GB for 1333 memory).

A P55 mobo (e.g. P7P55D) has four dual channel DDR3-1333/1066 memory slots.

Does the above mean that these are the correct configurations?

For 8GB: two of 2 x 2GB taking all four slots, for $200
For 12GB: one of 2x4 and one of 2x2 taking all four slots for $500
For 16GB: two of 2x4 taking all four slots for $800

What would you recommend?

 

[avin]

I found out that x58 motherboards has six memory slots, and that a 6GB (3x2GB) triple channel kit just costs $150. Does this mean I can populate 12GB for just $300?

 

[Blkout]

I found out that x58 motherboards has six memory slots, and that a 6GB (3x2GB) triple channel kit just costs $150. Does this mean I can populate 12GB for just $300?

Yes, but your i7 860 isn't going to work with an X58 motherboard, that's a 1366 socket, not 1156.

 

[avin]

Sure, sorry I wasn't clear on this: )
I do NOT have a processor or a mobo yet. I'm trying to decide what to buy - 860/p55 or 920/p58.
Right now, I'm favoring the 860/P55. I want to verify that indeed, the memory configurations and pricing I've specified in the first message are correct.
Incidentally, having found out that X58 mobo has six memory slots, I thought that maybe a 12GB configuration could be had for $200 cheaper than on a P55 board, and I wanted to check this out.
So, indeed, there are three questions here:
1. Are the memory configurations and pricing in my first posting correct?
2. Could 12GB be had on a P58 so much cheaper, taking advantage of 12=6x2 instead of 12=2x4+2x2.
3. If both 1 and 2 are correct, should the lower cost of 12GB on the X58 move me to 920 (or 930) and P58, offsetting the higher mobo prices?