Right now I'm in the process of buying parts for a build. My build is based around the Asus P8Z77-V LGA MB and OC i5 3750. The other day I found a sale on RAMM - Corsair 4g x 2 CMZ8GX3M2A1600C9B. I was happy with that when I ordered it but in doing some reading the last couple days I'm really leaning toward 16g of RAMM. My question is two parts.
1 - Can I just buy another set exaclty the same and add them to my other two DIMM slots for 4g x 4. Or would I need to send them back and get a complete set of 4g x 4? The model number is a bit different if I order this way but they all have the same timing and voltage.
2 - Is it better to run 4g x 4 to get 16g as opposed to 8g x 2 if the MB accepts either?
1 - Yes, you can just add another two sticks and it will work just fine since they are the same brand, timing, frequency and voltage.
2 - It is usually accepted as better to run fewer larger sticks rather than more smaller sticks. This is mostly just so that it is easier to upgrade in the future though since the performance difference is very, very minor.
So if you are in no rush, then going with 2x8GB would be better than 4x4GB.
Yes. There is no benefit to running 4 sticks, but overclocks will be better with 2 sticks. I would just get two more of the same, unless you want to go farther than 16GB any time soon, for like a Ramdisk or something.