I'm looking to upgrade memory in an older system running an Asus P5Q Deluxe MB. This supports DDR2 memory. It's getting tough to find the faster memory in DDR2 and I was wondering which will give better performance, a higher clock rate or a lower CAS latency? I've found DDR2-800 memory with CL 6 and DDR2-667 with CL 5. Any suggestions?
I'm looking to move up to 8GB and I'd prefer to go with a 2 stick kit instead of 4. I think I'm lucky though and may have just got the last 2x4GB kit of DDR2-800 CL5 memory that Newegg had. It was in stock, I ordered it, and now it says it's shipped, but the product page now says it's out of stock and discontinued.
Based on your last statement that DDR2-800 CL6 and DDR2-667 CL5 have the same latency, I take it that it the DDR2-800 would be better. Hopefully I won't have to worry about that though.
DDR2-800 CL6 and DDR2-667 CL5 should basically perform the same. The lower the latency at a given speed, the faster they are. DDR2-800 4GB modules are CL5 or CL6. My G.Skill 16GB CL5 kit (4 x 4GB) has been very stable at 1.9v and default timings.