Is different speed and brand ram relevant?

[Devon_20]

so im putting new ram in my motherboard (which supports a maximum of 2133mhz) and because im a cheapskate im using ram that i had previously and a stick that was donated by a friend. 1 stick is 2133mhz Kingston and another is 2333mhz corsair vengeance lpx. And will having different speed and brand effect efficiency in my pc? i believe the 2333 will be automatically under clocked to 2133 i think.

 

[Aeacus]

I believe that you can't get both sticks running at all. Mostly because different RAM manufacturers time their RAM differently.

For 2 RAMs to work together, CAS latency, timing and voltage must match. While voltage on most DDR4 RAMs is 1.2V, the CAS latency and timing will vary greatly between manufacturers.

 

[RustMate]

Dont do it, it will crash your computer you best bet is just to get new ram all same brand or find a mach between your other ram . JUST DON'T DO IT

 

[SchizTech]

Yes, the system will run all RAM at one common speed, the best speed supported by all sticks. That works out to the speed of the slower stick. Mixing RAM isn't ideal but if it works it works. The speed of RAM has less impact on overall performance than CPU in general.

 

[SchizTech]

I believe that you can't get both sticks running at all. Mostly because different RAM manufacturers time their RAM differently.

For 2 RAMs to work together, CAS latency, timing and voltage must match. While voltage on most DDR4 RAMs is 1.2V, the CAS latency and timing will vary greatly between manufacturers.

It's far from a sure thing but as a tech I've seen systems come in the shop with mixed sets of RAM that get along. I wouldn't advise it for a new build or general practice but it's not impossible.

 

[Aeacus]

It's far from a sure thing but as a tech I've seen systems come in the shop with mixed sets of RAM that get along. I wouldn't advise it for a new build or general practice but it's not impossible.

Have those builds with mixed RAM also been builds with DDR4 RAM or with older, DDR3, DDR2 and DDR1 RAM?
Asking it because older RAMs (DDR3 and prior) seem to have tighter timings and finding two mixed RAMs with same timings seems to be easier than same thing on DDR4 RAM where timings vary greatly.

Also, isn't there any damage for a RAM that has to work slightly out of it's timings to work with slower RAM?

 

[SchizTech]

The shop where I work deals mostly with "common man" systems, often lower cost or older. The number of DDR4 systems to come in so far is probably small.

Mixing RAM would seem to increase the chances for issues, sure.

 

[Devon_20]

My current build is ddr3 with mixed ram and it works like a charm but i didnt know if it was a flook

 

[Aeacus]

My current build is ddr3 with mixed ram and it works like a charm but i didnt know if it was a flook

I'd say that your working DDR3 build with mixed RAMs is a fluke.

For DDR4 and as said by many users above, do get two exactly the same RAMs for best compatibility.

Though, even if you get two exact same RAM sticks (bought each stick separately), there's still a chance that they don't work together.

RAM manufacturers (e.g Corsair, Kingston, G.Skill etc) make RAMs and test if they work together or not. If RAMs work together then they add them together and sell them as a set. Either as 4 stick in set or 2 sticks in set. Those sticks that doesn't want to co-operate are sold separately and one at a time.