RAM upgrade pairing

[Oxmaster]

1 year ago I bought really cheap RAM for my PC 50$ for 2×4GB Patriot Viper Div2 1600 MHz CL8
but now I want to upgrade and I now it's out of stock everywhere. My questions are:

Can I have 3×4 GB of RAM?
If I want to look at other brand does the timings and voltage matter? Most of the dimms have are CL9 and not 1,65V.

Mobo: MSI Z77 G55
CPU: i5 3570K

 

[Justin Millard]

You won't be able to run 3 sticks of RAM with that setup instead you need four identical sticks of RAM in all four slots if you want to keep your current RAM. With that setup you can have 1 stick of RAM, two sticks of identical RAM in the right slots or four sticks of RAM in all slots.

If you had three sticks of RAM I don't think it would recognize the third as it would be an asymmetrical setup.

 

[Eximo]

1600 CL8 is actually pretty good. As well as 8GB. Are you actually utilizing it all with a game or application?

You can install a third stick, but ideally you want matched pairs. (The pairs don't have to match, they just need to be able to do the same speeds and timings, in general)

My suggestion would be to buy a nice set, 2x4GB, of 1.65V 1600Mhz CL9 memory, and run all of them at CL9 timings. You won't notice the performance difference doing that, and you will gain the memory.

 

[Eximo]

You won't be able to run 3 sticks of RAM with that setup instead you need four identical sticks of RAM in all four slots if you want to keep your current RAM. With that setup you can have 1 stick of RAM, two sticks of identical RAM in the right slots or four sticks of RAM in all slots.

If you had three sticks of RAM I don't think it would recognize the third as it would be an asymmetrical setup.

It would run them as long as they all run at the same settings, but they would only run in single channel mode, rather then dual channel mode.

 

[Oxmaster]

1600 CL8 is actually pretty good. As well as 8GB. Are you actually utilizing it all with a game or application?

Yes I need more RAM, I'm using PS, and other stuff and I can see RAM usage at 90% and SWAP usage at 85%.

So basically buy another set of 8GB with CL9 and downclock my current one.
And about voltage, should I give my old RAM less volts if I'm going to buy 1,5V, or try hard to find 1,65V.

Getting CL8 now is very hard, can't see any good offers. Can someone recommend any CL8 for under 60$?

[strike]Would be there big performance hit, when using single channel for 12GB?[/strike]
Did some research:
http://www.gamersnexus.net/guides/1349-ram-how-dual-channel-works-vs-single-channel

 

[Justin Millard]

Sorry I did have that completely wrong. Yeah, it should run them all in single channel mode. So you will take a slight hit on speed in your photo shop tasks, but you will have more RAM available. I'd argue that unless your hitting an error message saying low RAM then there is no need to upgrade. The 90% usage just means its being used really well by the system.

If there is a slight difference between the RAM speeds they should all work at the same speed as the slowest stick. But try to get their timings exactly the same beforehand. I'm guessing the CL8 RAM you have is already being overclocked to hit that speed so you should be able to downclock it or overclock new ram to the same timings. Never mix the voltages on RAM. They are very unlikely to work together if you do that.