How do I check the CAS latency of my RAM?

[DyslexicHobo]

I decided that I'm going to purchase another stick of 512mb DDR400 RAM for my PC (to add to the already existing 2x 512 sticks of Mushkin), and while I was doing some research I saw that conflicting CAS latencies can cause problems. Is mixing RAM with different CAS latencies really a big deal? I've heard from some people that it's not a problem, but will run at the higher of the two CLs, but I've also heard that it can cause some major problems to run RAM with different CL ratings. My current Mushkin sticks run at 2.5CL with timings of
3-3-8-12. The new RAM I'm planning on buying is G. Skill with timings of 3-4-4-8. Its CAS latency is 3.

So that brings two very important questions:
1) Will this RAM be compatible?
2) Will this RAM be beneficial to my system, or because it's lower quality RAM, will it bring down the overall performance of my system?

I really don't understand any of this CL or RAM timing thing at all. Thanks for any help

 

[Mrfrog840]

i also want to know as I have 2gb sitting here I could install, but they are not matching what I have currently in my pc!

 

[jpeyton]

http://www.cpuid.com/download/cpu-z-138.zip

 

[DyslexicHobo]

Originally posted by: jpeyton
http://www.cpuid.com/download/cpu-z-138.zip

Yeah I just remembered about that program after I posted my message. Thanks for the link, though.

 

[Zepper]

Any system info program that can read the (SPD) ID ROMs on the modules can do that.

.bh.

 

[DyslexicHobo]

Bump. if anyone has even a little bit of experience in combining RAM of different CL/timings, please let me know how it worked out!

 

[Zepper]

I have done it back in the day of SDRAM. All you might have to do is punch the values into your BIOS setup manually if your mobo balks. Just put only the slowest one in alone, set the timings manually, shutdown, install the faster one. Boot up and all should run fine.

.bh.

 

[MercenaryForHire]

Originally posted by: Zepper
I have done it back in the day of SDRAM. All you might have to do is punch the values into your BIOS setup manually if your mobo balks. Just put only the slowest one in alone, set the timings manually, shutdown, install the faster one. Boot up and all should run fine.

.bh.

And then from there, you can try to tweak a little tighter timings out of the slow RAM if you want.

- M4H

 

[GuitarDaddy]

Mixing rams with different timings is not a problem, the board will run it all at the highest timings.

I sounds like you have 2x512 and are adding another 512 stick? If thats the case you will lose the benifiet of dual channel (3-5% performance hit)

If your adding a 1gb stick you can run dual channel by switching your exsisting sticks to like colored slots and putting the 1gb stick in the other color(channel)

 

[DyslexicHobo]

Ah... didn't think about losing dual channel. The only reason I was even wanting to add this other RAM is because I can get it for dirt cheap (~20$), but I'm limited to buying one stick. Even with the loss of dual channel, will the 512 still be a gain in performance if I set it to the faster RAM's timings?

 

[Lonyo]

RAM timings are global, they apply to all the RAM in your system.
As long as you set the timings to suit the slowest/worst RAM you have, it should be OK.
Rated timings are just what it's certified to run at, you can run it out of spec if you want, but that's where problems can occur.