Ram upgrade what is CL ...

yumzone

Hi there im upgrading my RAM and during my sarch for suitable memory I have found many sticks of PC3200 but some with a CL of 2.5 and some with a CL of 3 .... what is the CL and does it matter I have used the crucial memory checker and it says CL 3 ... will CL 2.5 not work?

marka87uk

I think it should work? I can't remember what the CL is (to do with latency though?) but you can change it to 3 in the BIOS probably anyway (depending on the BIOS/mobo). It will just be running slightly poorer than it could be (wouldn't be noticeable though).

Toxteth_OGrady

Good explanation of memory basics here. CAS latency is # 21.

CAS latency is the timing of the memory and thus the amount of data it can process over a given period of time (clock cycle). The lower the CL (2 is lowest/fastest --> 2.5 --> 3 --> 3.5 is highest/slowest) the faster the memory. CL 2 memory chips have the tightest manufacturing tolerance and are the most expensive.

CL 2 RAM will not however work with any old motherboard/chipset/psu combo, so before buying CL 2 RAM it's worth checking that your mobo/bios supports it and your psu can push out sufficient Vdimm to power the RAM at that speed.

If they cannot, your CL2 RAM will automatically adjust/underclock itself to CL3 but you will have wasted money when you could have just bought cheaper CL3 RAM in the first place.

As for performance, you will get about a 10% improvement in memory bandwidth going from CL 3 to CL 2 - so if you're into gaming or video editing then I'd recommend CL 2.

HTH

:cool:

TOG