Overclocking the Asus P5W w/ 4 DIMMs

[cbuchach]

So I recently bit on one of those cheap deals for 2 GB of RAM to upgrade my system from 2 GB to a total of 4 GB. I was running my Asus P5W with a E6600 at an FSB of 392 with the FSB:Memory ratio at 1:1. I had this running at CAS4 timings with 2V on the RAM and default voltages on the chipset.

Before upgrading I knew that having 4 DIMMs installed could limit my overclock. I just first popped the DIMMs in and booted up Windows memory test which immediately failed. I then increased the memory voltage to 2.2 (the actual default for the Crucial Ballistix memory I have), and dropped down to 5-5-5-18 timings and passed Windows memory test. I then loaded up Memest 1.70+ and got a failure on test #5, the block move test, which I found is somewhat sensitive to FSB overclocks. I then tried tweaking the MCH and FSB termination voltages but with the same results. THe systeme will boot Windows, but I of course don't like it failing Memtest.

So before I return the two extra DIMMs, I was wondering if anyone has had any success at running the P5W at high FSB speeds with 4 DIMMs installed? and what those speeds might be and how you did it? as I would like to run with 4 GB of RAM but will not sacrifice stability or a significant percentage of my overlcock to obtain it.

I should add that the memory was all the same, the Crucial Ballistix PC6400 CAS4 2.2V stuff. And that the system is completely Memtest, Orthos, etc. stable with 2 DIMMs installed running a 9x392, at 1:1 timings, 4-4-4-12, 2V memory, and default MCH and FSB voltages.

 

[myocardia]

Originally posted by: cbuchach
Before upgrading I knew that having 4 DIMMs installed could limit my overclock.
Topic Summary: My FSB topped out at ~385 MHZ...

So, what's the problem? You've gotten a better overclock with 4x1 GB than most people do.

 

[cbuchach]

So around the ~380MHz FSB range is about the best I can expect for 4 DIMMs?

 

[myocardia]

No, but higher FSB is going to require much higher vdimm, compared to 2 sticks. For instance, with 2.4-2.5v of vdimm, most people's D9GMH's will do ~550-600 Mhz, yet that's about what I hear they require to go above 400 Mhz, when using 4 DIMM's.

 

[cbuchach]

Originally posted by: myocardia
No, but higher FSB is going to require much higher vdimm, compared to 2 sticks. For instance, with 2.4-2.5v of vdimm, most people's D9GMH's will do ~550-600 Mhz, yet that's about what I hear they require to go above 400 Mhz, when using 4 DIMM's.

I am a bit wary of going that high on my memory without active cooling of some sort. I just tried with 2.3 V and Memtest still failed.