DDR400 ram running at 333mhz!

[DrAsik]

Since I added a second 512MB stick of ddr400 ram on my Asus P4S800 motherboard, my ram is running at 333mhz instead of 400mhz. This is pretty bad considering my processor's FSB is 800mhz.

I tried to edit that in the bios but forcing 400mhz prevented the system from even POSTing. I was lucky I could get into the bios and reverted the setting back to "Auto", which it considers is 333mhz.

Is there any other way I can get that ram running at it's full speed?

 

[franklin97355]

Have you tried the new stick by itself?

The answer is "42"

 

[Freestone]

Is the memory you are using listed in the motherboard manual's qualified DDR 400 memory module list? Page 1-13 of the manual I downloaded, and this list is short.

 

[DrAsik]

Each stick can run at 400mhz individually, but when they are used together they can only run at 333mhz.

The memory I just added is listed in the manual, but the old one is not.

 

[DrAsik]

My old RAM is Elixir M2U51264DS8HB3G-5T, Unbuffered DDR DIMM. The other one is Samsung K4H560838E-TCCC (Can't find spec sheet)

 

[DrAsik]

I did some benchmarks:

3DMark05:
512MB ddr400: 1100
1024MB ddr333: 1098

Not a big deal, you might think. Yeah, but I was rather expecting an amelioration of performance by adding more RAM, certainly not a degradation, even if it's insignificant.

 

[Freestone]

The Samsung number you gave is for a 256Mb (32Mx8) chip. I found its specs here:

http://www.intel.com/technology/memory/ddr/specs/DDR400 256Mb_E-die_x8_r1.1.pdf

When you set the memory to DDR400, did other memory timings change? Both of your DDR sticks require a CAS Latency of 3. The two sticks' specifications look very similar. I don't know why they don't play well together at 400MHz. Timings for both are 3-3-3

Since the new stick you added is in the manual, perhaps you may want to try another of the same exact type?