ram compatibility

[Atlant]

if i have one stick of ram installed what i need to check before i buy the second stick to know that they will be compatible?

does the Mhz needs to be equal? and what about different manufacturers

[zMeul]

you should buy the exact same model as your existing RAM module to minimize incompatibility

[Trevor87]

You need to check Mhz are same and CAS are the same as well. If you get a decent brand of ram you should good.

[Kitten of the Broccoli]

I don't know everything there is to know about RAM, but I have 2 DDR3 DIMMs that are at 1600Mhz, and another 2 at 1866Mhz, so I don't think a difference of frequency matters. It might not matter, but if your MOBO has 4 RAM slots, I'd suggest putting the RAM DIMMs in 2 different channels(right next to each other). From what I've learned, putting 2 different DIMMs in the same channel could potentially cause problems. Extreme emphasis on potentially, as you might not experience any issues.

[Kitten of the Broccoli]

29 minutes ago, Zomicron said:

Are you saying you have two different speeds running in your pc? If so, is the 1866Mhz actually running at that speed or is the computer making it run at 1600Mhz?

I have 4 DIMMs total(all G.SKILL Ripjaws): 2x4GB @ 1600, and 2x4GB @ 1866. I don't know if it's because I have XMP enabled or what, but Task Manager says that the speed of my RAM is 1867MHz, but in my BIOS they all say 1600.

[Atlant]

11 hours ago, zMeul said:

you should buy the exact same model as your existing RAM module to minimize incompatibility

i cannot find it on amazon

11 hours ago, Trevor87 said:

You need to check Mhz are same and CAS are the same as well. If you get a decent brand of ram you should good.

what is cas? im getting a higher Mhz secondary ram stick, from the comments i understood that they will run both at a lower frequency but that it works.

i checked the pins, both have 204 = is this CAS or the voltage they both have 1.35v?

[Trevor87]

It makes a good read  http://en.wikipedia.org/wiki/CAS_latency