Ive read countless forums and tried many reference overclocks, but i cant seem to match them. Ive seen the posts that most users can get there Opteron 185 to 3.0Ghz by FSB 250x12, 1.41v and lowering the ram timings.
If i try lower FSB and run anything more than 220x12 the machine locks. However by using the 13 multiplier it works fine. I have it set stable with prime at 220x13 with standard mem timings -- 2.5-2-2-5. This gives me a 2900Mhz core. Should i be able to get it to 3000Mhz stable, or would it be too much effort/work/cost to worry about a 100Mhz increase?
I was wondering if any other user has my setup and what have you achieved with it, and how?
ASUS A8N-E Motherboard
Opteron 185 Denmark DC
4x512 Corsair CMX512-3200C2 Timings 2.5-2-2-5
Note..because im uing 4x512, this board will not read the modules past 333Mhz so im doing my best with this. It wil only run 2 moduls at 400Mhz. Could this be the problem? Ive tried slowing the RAM to 266 and 200 to increase FSB but the board just does not seem to like the 12 multiplier.
Would running 2x1024 mem modules fix my problem, or improve my chances of reaching 3000Mhz.
I don't do much overclocking, but I toyed with it on my old socket 939 3500+ single core, what I did was drop the HT multiplier to 4x. See AMD uses the multiplier off the chip, so you can do more FSB x Higher multiplier=more speed. The other side is your HT Link multiplier. I think without touching CPU multiplier, and with ddr 333 memory, I think I got up close to 2.7 ghz, when you consider the chip was only like a 2 ghz processor to begin with...I think....that was a decent increase.
By default, HT=1000, so if we know that, then we know AMD usually sets HT multiplier 5x by default.
5 x 200 mhz FSB=1000 HT speed, correct? When that HT gets too high, the mobo does not like that.
Way to fix that is drop your HT to 4x
So we could say for example....
4 x 250=1000 HT, so same result for HT speed, but you get higher clock speed from your CPU.
So if you can do say that, plus a higher multiplier, considering your mobo and ram can handle it, you should be able to get closer to your max OC.
As far as I know, I think having 4 modules can mess with some things. But I also think that a performance difference between 2.9 ghz and 3 ghz would be very little when compared to you are going to spend probably 100 bucks to get 2 gb of ddr ram. Easiest way to do some countering, set a ram divider in your bios, like my old board, I could manually set my ram to run at 166(333 mhz), see you could do that, but as you increase FSB, it will force your ram to run faster, so therefore you may actually get toward what your ram really is supposed to run at, but still get the faster core clock on your CPU.
Hope some of this helps you out, just make sure you have good cooling, and if it gets unstable, some guys say you may have to raise voltages slightly.
Yea, if you havent reduced the HT multiplyer it could be your problem. It doesnt take well to being clocked over 1Ghz, so try to keep it there or below. Many tests have showed that it doesnt affect performance, so if its only running 700-900Mhz, dont worry about it.