I've done a little looking but can't seem to find the answer that eludes me. So what exactly is CL2 ram? I've also heard it referred to as CAS2 ram, are these two different names for the same thing? Also, I've seen it referred to as CAS2 and CAS 2.5, if I read it right CAS2 is better than CAS2.5, is that true? Lastly, how do I tell if a particular type of ram is CL2(CAS2) ram? Thanks.
I am guessing that you have searched the forums here. If not please do.
CL = CAS Latency.
CAS = Column Access Strobe
Memory is basically a matrix of capacitors set up in a set of columns and rows. (Think of it as a big spreadsheet.)
The memory is accessed first by the column and then the row. When dealing with CL2 and CL3, the column is accessed and then the row. When the memory is looking for additional information that is not contained in that row it has to start the process all over again. This is where the CL part comes in. With a CL2 there is a delay for the strobe to complete. So under regular operation it would be 1 regular access cycle + the CL penalty. That would be 3 cycles for CL2 and 4 cycles for CL3 in order to prepare data for output. (For DDR it is a little different but basically the same. DDR SDRAM uses clock forwarding and thus is faster than SDR SDRAM)
Keep in mind that this is only one latency timing. There are a bunch of others.
For all intents and purposes, CL2 is CAS2 RAM. The proper terminology is CL. (CAS Latency)
CL2 is one half clock cycle faster than CL2.5 and one full clock cycle faster than CL3. It is faster because the delay is shorter.
There are ways of telling what RAM you have. Is it DDR or SDRAM? The chips themselves can tell us what they are and there are tools to read the SPD chip on the memory PCB. You can find that tool in the FAQ on the top of the Memory Section here in the THGC posted by Master <b><font color=green>Fatburger</font color=green></b>.