Mixing RAM?

[Essence_of_War]

I know RAM should be installed in identical, matched, pairs.

But if I have 4 RAM slots, should each slot be identical, or do only pairs of slots need to be identical?

Basically I have 2 sticks of RAM already installed, I was thinking of getting an additional 2 sticks that have the same voltage, speed, DDR3, but have different timings. Would this a problem?

 

[Mushkins]

Ideally, you want it *all* the same. Practically, what you want to do is acceptable.

However, you should get RAM with the same timings. Depending on how the mobo/bios wants to play it, mixed timings will either default both sets to the slower timings, do... something in the middle, or throw a fit and not work. You can mostly get around problems by manually setting the timings for both sets to the slower timings, but since you havent purchased yet why not just make sure and match the timings?

 

[Essence_of_War]

Good to know! Thanks!

 

[Insert_Nickname]

Ideally, you want it *all* the same. Practically, what you want to do is acceptable.

However, you should get RAM with the same timings. Depending on how the mobo/bios wants to play it, mixed timings will either default both sets to the slower timings, do... something in the middle, or throw a fit and not work. You can mostly get around problems by manually setting the timings for both sets to the slower timings, but since you havent purchased yet why not just make sure and match the timings?

When I mix-and-match memory I just manually set the timings to the slowest DIMM. Should work fine and tight timings are not as important as they used to be...

 

[BrightCandle]

I have run mixed sets in the past, you just end up using the slowest settings and all is fine. The performance impact is measurably small and its not a concern.

 

[Sheep221]

I have been used combined various RAMs many times, the settings and everything will automatically set up to lowest module and everything will be fine.
Populate those slots! :biggrin:

 

[cbk]

I think it is fine, as long as you make sure you underclock or overclock the RAM to all the same frequency.

 

[mystixa]

I thought this answer was fine as well, since mixing 2 and 2 has worked for me several times before. With the asrock z77 pro4 however it wants identical. It says identical in the manual, and it really means it. I upgraded to this one and had 4GBx2 pc3 1600 and 2x2 pc3 1600 on hand, it didnt like it. Traded to 4x2 1600 and 4x2 1333 (got those out of my GF's pc), and no go. All of these worked fine as a pair by themselves. The motherboard wants the pairs in every other slot as normal, for those wondering about placement. It appears the dimms need to be the same size and speed as well. It at least needs to be a closer match then indicated above.