Dumb Question-Running "faster" RAM at lower speed and lower latency

[JackHawksmoor]

I'm planning on building a new system soon, and I'm trying to figure out what RAM to use. Anandtech's high-end buyers guide recommends this:

http://www.newegg.com/app/ViewProductDesc.asp?description=20-146-294&depa=1

Mushkin Level One Dual Pack, which is PC3500, 2-3-3, and the guide shows it as being "CL-2".

My (dumb) question is, can you run that RAM at PC3200, CL-2 (2-2-2-6 or whatever that would be) since the lower clock speed should allow it to hit lower latencies?

Would the SPD info on the chips tell a motherboard to default to PC3200 CL-2, or would it default to the higher latencies that it's rated for at PC3500?

As long as I'm asking, should I avoid Mushkin? I usually buy Crucial, but they only have CL-3, and Corsair's more expensive (not even sure if they've got CL-2 RAM or not). For that matter, should I just save $50 and go with CL-3 or CL-2.5 RAM?

Okay, I didn't intend to start asking all these questions, but...
i865 or i875? Worth a $40 difference? So many choices...

Thanks!

 

[MercenaryForHire]

IIRC, if everything (memory speed and timings) are set to Auto, it will default to the highest speed and its internal timings.

If you force the speed to something slower - like PC3200, which is better if you have a 400FSB Athlon running in sync - then it should have another internal set of SPD timings to meet the JEDEC DDR standards. And yes, they should be lower latency timings.

For example - my Micron DDR modules (which I just traded) had two sets of SPD info - one for 266, one for 333. At 333, it ran CL-2.5 and more relaxed timings. 266, it dropped to CL2 and lowered the latencies a notch or two.

- M4H

 

[JackHawksmoor]

Interesting. Thanks for the info! I'll have to think about this some more.