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Bios Settings for DDR400

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October 21, 2004 8:34:01 PM

I have a Gigabyte mobo, with an XP 3000+ and 1G of DDR400. The settings in my bios are very confusing, as there are so many...Anyone who knows what these should be, please help...Here are my choices:
DRAM burst length-4 or 8
DRAM Que depth-2,4,3 level
DRAM command rate-1T or 2T
Write recovery time-2T or 3T
DRAM +WTR-1T or 2T
Fast command-normal, fast, ultra
CAS latency-2,2.5,3
Bank interleave-
Precharge to active-2,3,4,5T
Active to precharge-6,7,8,9T
Active to CMD (Trcd)-2,3,4,5T

Any help would be appreciated :) 

More about : bios settings ddr400

October 21, 2004 9:48:17 PM

That depends on the ram in the system (brand, quality, specific molecular quality of the chip inside, etc.) and the motherboard (some are more finicky, some drive RAM harder, etc.).

If there's a 'by spd' setting you can make, make it. That tells the mobo to read the settings on the dimm and you're all done.

If not (and I'm 99.9% certain there is), there may be some settings printed on the ram itself that tell you where to start. If you see numbers on the RAM like "2-2-2-6" that is (and the order may be different - I never remember it right...): CAS Latency - Precharge to active - Active to CMD - Active to Precharge.

Then the rest is for enthusiasts that want to play around and get the best performance out of their memory they can.

General basic starting point for ddr400 ram is: (now, some of these numbers are my wild guesses because I haven't seen anything informative on them and have always used "by spd" on my mobos)

DRAM burst length-4 or 8
--> Either is probably fine.
DRAM Que depth-2,4,3 level
--> Level would be my guess.
DRAM command rate-1T or 2T
--> 2T is safe, 1T is faster if it works
Write recovery time-2T or 3T
--> 2T usually
DRAM +WTR-1T or 2T
--> 2T is safer, 1T is faster if it works
Fast command-normal, fast, ultra
--> Start at Normal, make fast if you want to play around and see if it works.
CAS latency-2,2.5,3
--> This is very memory dependent, industry specification is 3, many (most?) can do 2.5, high quality low latency can do 2.
Bank interleave-
--> Yes, Active, etc. if you have multi-bank RAM.
Precharge to active-2,3,4,5T
--> Spec is 4, good ram can go as slow as 2.
Active to precharge-6,7,8,9T
--> Spec is 8, good ram can go 6
Active to CMD (Trcd)-2,3,4,5T
--> Spec is 4 I think, good can go 2.

Hope it helps.

Mike
October 21, 2004 11:19:33 PM

Yeah, it has the by speed setting, I was just wanting to know how to optimize to reach full potential, speed etc...
Oh, I almost forgot...I have 2 512MB Crucial sticks.

<P ID="edit"><FONT SIZE=-1><EM>Edited by Tomas6139 on 10/21/04 09:12 PM.</EM></FONT></P>
October 22, 2004 2:54:52 PM

Ok, that's a long process...

Make a setting change, run a benchmark/stress test program for a couple hrs to make sure it's stable. Note the speed rating from the program.

Make another setting change, run a benchmark/stress test program for a couple hrs to make sure its' stable. Note the rating.

Etc.

Its a complex relationship, all those settings - you may be able to reduce one to the minimum while leaving another higher, and that gives you a better speed rating than having both those settings 1 step above minimum... but I don't see it as worth that much time myself. Most bios have a couple settings like 'default settings', or 'performance', 'optimized', 'turbo' or 'fast'. That may be a way to quickly set the agressive timings and see if your ram can handle it.

Another thing - if your ram's CAS latency (usually the first number 2, 2.5 or 3) is 3, try running it at 2.5, and if 2.5 try running it at 2. Sometimes the memory can handle that setting, and it makes a noticeable performance difference.

Mike.
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