which is more important?

[its snoodles]

ok so i am looking to upgrade my RAM after i upgrade my processor so i need to know on an AMD build which is more important when it comes to ram is it better to have a low CAS latency and tighter timings? or is it more important to have higher frequency because i want to get the 2000 MHz DDR3 which is the highest my motherboard supports and i need to know which is more important for AMD. i have heard alot of people say that on intel processors that the frequency matters more the timings but im not so sure for AMD.

 

[Indigo]

on an AMD platform, you're not going to be as memory bound as you would be on an Intel system. In your case, just pick the one you want to go with and do it. Reviews lately on AM3 have proven that you don't really need to aim for a lower latency or higher frequency. In most cases, unless you're performance tuning your system, you can buy the value RAM for an AMD system and it will perform 95% as well as the high end stuff. You have to decide if it's worth it to spend the extra $20, $40 or more for the tighter timings. I use the Black Line from Mushkin on my Phenom II at home, and it's plenty fast.

 

[its snoodles]

well because i was thinking about getting 2000 Mhz RAM just because im trying to get the most out of my system as i can but instead im thinking of just getting the 8GB set of the ripjaws from Gskill i did a build for one of my friends and he uses the 1600 MHz Gskill ripjaws and his rig runs great with them. i just need to upgrade my RAM because my 1333 without heatsink are just not fast enough.

 

[Indigo]

The performance dividend on AMD systems isn't worth it to upgrade to higher clocked memory because the performance difference just isn't that high. 5-10% is what I've seen from those kinds of modules.

Some great examples:

http://www.anandtech.com/show/2050/2 (AM2)

and here are some DDR3 speed and latency tests:
http://www.legionhardware.com/articles_pages/amd_am3_memory_performance_guide,3.html

It's just not worth it for such a small performance gain to spend so much more on memory that isn't performing all that much higher.

I mentioned that I run Mushkin black line in my system at home, but I didn't mention that I run with all of my slots full, so my DDR2-1066 modules only run at DDR2-800 speeds (CPU limitation), but the performance loss, even accounting for the drop in size (when I tested the speed difference, I only had 4 of the 8 GB installed, which was two dimms) the performance gain was only 4% on each test, at the most. AMD's DDR3 memory controller is no different.

It's not that AMD's memory controller sucks, it's just that their architecture just doesn't NEED the insane memory bandwidth requirements that Intel's i-series CPUs does.