I've actually posted myself a few times in regards to this issue. I have had NOTHING but BAD experience with 4 slots filled. Number one you will NOT be able to run 1T -- at least I never could. Also I had to relax my timings and to add insult to injury, my original board (as a result of the limitation with my AMD64 3200+) could not handle 4 DIMMS (double sided) unless you brought the speed down to 333MHz instead of the 400Mhz. Now if you can find single sided -- but that's a joke and not worth it.
As for actually oc'ing, you've lost already so much performance from what I described above that you are starting at a loss. You can OC and I did successfully but I found it to be way more flaky than it would be with say just 2 X 512.
I finally broke down and got 2 X 1024 and life has been good ever since -- I sold my 4 X 512 and did not lose too much in that.
In a recent review of overclocking on Anandtech.... here is what was stated (directly from the article):
One area where we experienced serious problems was in running with four DIMMs. First, as expected, a 2T command rate was required. Even then, using four OCZ EL Platinum DIMMs, we were only able to complete benchmarks at 2-3-2-7-2T timings (2.8V) at default CPU clock speed. All attempts to get the system to run stable in any overclocked state of 2200 MHz or more met with failure. Winstones could run successfully in almost every instance, including 2.5-4-4-8-2T timings at 2700 MHz, but Battlefield 2, Far Cry, and FEAR all crashed (hard-locked the PC) repeatedly. Test #5 in MemTest86 also failed with display corruption. Attempts to tune the RAM better met with limited success. By changing the EQ Drive Strength to "Weak", we were able to get further in testing, but nothing was truly stable. We would venture to say that the RAM is not to blame, as both pairs of DIMMs worked separately. The most likely culprits are the motherboard and BIOS, which are not as highly tuned as many enthusiast motherboards.
Bob
Facebook
Twitter