Need more RAM, does CAS latency need to match current RAM?

[Stinkfinger]

There's currently a gig of Corsair DDR3200 in my pc, its running in dual channel mode. I'd like to add another 512MB. Does the CAS latency of the new ram need to be equal to or faster than my current ram to keep it from slowing down all of my system ram? In other words, if I don't get the same CAS as my current ram, will all the ram run at the lowest (slowest) timings?

 

[CalvinHobbes]

Dual channel will no longer work and I would imagine that either you'll need to match the timings of the new memory to the old memory or the other way around. It may work fine depending on the memory. What do you need the extra 512MB for? If you really need more ram, get 2 x 1GB so they'll match.

 

[NoBull6]

Yes, when you put new RAM in, it will run at the slowest timings. If they are the same, you're all good.

Just match the latency on the current RAM instead of spending money on something faster that will default to slow speeds anyway once you install it with old stuff.

 

[Stinkfinger]

Originally posted by: CalvinHobbes
What do you need the extra 512MB for?

I'm a Battlefield fiend and with the new game coming out real soon I wanna make sure there's enough beef under my hood.

 

[Stinkfinger]

Originally posted by: NoBull6
Yes, when you put new RAM in, it will run at the slowest timings. If they are the same, you're all good.

How do I check my timings? Its been a while since I threw away the packaging.

So If I add another 512 the gig I have in there now won't run in dual channel mode any more? What if I were to add two 256MB matched sticks in the remaining two empty slots, will everything continue to run dual channel?

Would adding another 512MB be a significant perfomance jump justifying losing dual channel mode?

 

[Ike0069]

What socket do you have? If you have S939, it won't boot with 3 sticks of RAM. You have to use 1,2, or 4.

Either way though, I agree that you are better off staying with 1 GB, or getting 2 GB's and keeping dual chanel.

 

[Stinkfinger]

Originally posted by: Ike0069
What socket do you have? If you have S939, it won't boot with 3 sticks of RAM.

S939 supports Athlon 64s right? If so that's what I have.

 

[Ike0069]

So does S754, and you can use 3 sticks with that.

Easy way to tell.
If you have only 3 RAM slots, you have S754.
If you have 4 RAM slots, you have S939.

 

[RichUK]

Originally posted by: Stinkfinger
There's currently a gig of Corsair DDR3200 in my pc, its running in dual channel mode. I'd like to add another 512MB. Does the CAS latency of the new ram need to be equal to or faster than my current ram to keep it from slowing down all of my system ram? In other words, if I don't get the same CAS as my current ram, will all the ram run at the lowest (slowest) timings?

the simple answer to your question is yes

 

[NoBull6]

Memtest can tell you memory timings, but so can CPU-Z here.

 

[Stinkfinger]

There's nothing in Windows that'll tell me my timings? Pretty silly if you ask me.

 

[NoBull6]

Your BIOS should also tell you timings, if you don't feel like getting CPU-Z (although I recommend it - has lots of useful information in there)