You want eight gigs.

Four is a minimalist approach.  You're obviously a performance whore since you're paying for sli motherboards and overclocked ram.  A 64 bit Vista or 7 will use those four gigs without even trying, at the least, leave yourself the upgrade slots for another four.

If a motherboard has problems with all the ram slots being occupied, it's defective.

Get a better mobo.

790i = gay

Captain....

higher RAM speeds are in fact more prone problems if all DIMM slots are used especially if you are trying to overclock the RAM.

so yes, you would be better off with 2 sticks vs 4, or 3 sticks vs 6 etc.... depending on the board. 

if you want 4G go 2x2G, if you want 8G go 2x4G.

if a thriple channel board go 3x2G for 6G

go bump around the OCZ forums you will find all the RAM answers you need. and there you won't get any Jo Blow who thinks he knows what he's talking about answering your questions.there is only 1 section of the forum that anyone can reply to questions in, for all SUPPORT forums you have to prove you know what your talking about or be OCZ staff to answer questions.

just beware, they don't take to kindly to people asking questions about other brands of RAM. so if your not using OCZ just look around and read, if you post a question and they find out your running something other than OCZ they will direct you to that company's support.

If you are really a performance whore, stop playing with desktop motherboard... i have a two year old server motherboard who have the double of performance that a more new i7 975 processor/motherboard...

By example, a 3.0 GHz Core 2 Quad system using dual-channel 1066 MHz DDR3 achieved only 6.9 GB/s for memory transfer... Intel quickpath interconnect in the extreme edition of the i7 reach a bandwidth of 12.0 GB/S using triple-channel 1066 MHz DDR3... My old 5000X chipset use a quad serial channel interlaced memory connection and i have old FB dim ddr2 667 ( who can be upgrade to 1333 if i wish )... with these configuration, i reach a 32gb/s for memory transfer... because of the quad channel and the interlease, i need to use 8 of my 16 ram slot ( i have 8 time 2gb ram)...

My "mobob" is like a top MAC pro who have a tag price of 15000 euro... building myself a similar "mobob" have allow me to spare 10000 euro... case and mother board from supermicro, two quad core xeon, 16 gb ram, 8x500 gb samsung ( i am in the process to change them to 8x1TB ), two SAS drive for OS, blue ray, nvidia 8800 Ultra 768 mb, etc...

Somewhere on these forum, there is a topic related to benchmark... i have beat everybody, same the more recent "mobob"... and this without any overclocking... simply using the cheaper server board that i have found...

Maybe in a few year, when more modern desktop computer will be my computer, i will upgrade the processor and ram to 1333... but until now, i have not yet feel the need... what is good with server board, is that socket for processor don't change each 6 month... so, in the long term it is a cheap computer...