Opteron Wierdness

Okay - now, some of you may remember i had a go overclocking my opteron a couple of months back when i first got it, and i managed to get it just about stable enough to run superpi once, near the 2.9Ghz mark. Now with the new dividers that EpoX have added on to the 9NPA+ Ultra, for some reason, i decided that i'd have another go.

Wierd thing is, i dont know if its the new dividers that are helping, or my CPU has just gone mental on me - because now, i can run this at 1.5v (near enough as dammit), with the 150Mhz Divider (That actually defaults to a CPU/14 for me *sigh*) at exactly 2800Mhz, and the memory not exceeding 200Mhz (so it can run at 2-3-3-6).

It passes superpi 1m, 2m & 4m and i have no desire to test any higher, cause i believe its stable enough - but why would it suddenly run at higher speeds, at lower voltages now? Has months of being used at 2.4Ghz burned it in?? Has my computer entered the twilight zone??

Well, truly any of the things you listed could be the reason. Different multiplier/divider combos often end up more stable than others, even if they result in the same speeds, for reasons no one can quite explain. Your TIM might have settled in, you might have experienced a bit of the burn-in effect, etc. No worries, your proc isn't haunted.

However, I have to caution you about using SuperPI to determine stability. 1M, 2M and 4M are very easy to pass at low speeds. In fact, for me, my 32M stable speeds would crash out in games within 10 minutes or so. It would require about 50-100MHz less than max 32M stable speeds for true stability.

Well, before, at 2.8ghz, it had trouble passing even one instance of SuperPi 1M, the fact that its managing 4m with ease, and running all my apps makes me happy enough that its stable. I dont need to run Prime95 for 24 hours to say its 'stable' - I need to use the machine all the time

How about PCmark04?

Yet another piece of useless software to download

I hate benchmarking suites - even 3dmark i complain about - seeing as other than being able to show off to others with it - it doesnt *do* a lot :S

There are so many factors involved with compatibility between hardware and software, that being able to pinpoint the exact cause for increased or decreased performance is very very difficult.
Usually the best way to analyze such a situation is comparing results with users with similar symptoms.

I was suggesting something for (quick) stability testing really..

PCmark06 is pretty tough on a system, If I had to download just one more useless application I would try that one

Are you on dial-up or something?
Or just not wanting to waste you time?

Well, time is a major factor for me. I do a lot of video editing and encoding, which uses all the available CPU power. To take time out to run the benchmark means having to put off work for an hour or two. Secondly, the internet connection at university has gone from 4mbit to 640kbit, and at home, I have ReADSL and thats got even worse dropouts.

fordsierra4x4 said:

Well, before, at 2.8ghz, it had trouble passing even one instance of SuperPi 1M, the fact that its managing 4m with ease, and running all my apps makes me happy enough that its stable. I dont need to run Prime95 for 24 hours to say its 'stable' - I need to use the machine all the time

Click to expand...

Well put. Stable is a relative term. Being stable for 24 hours in prime only makes you "prime stable" and nothing more. Sure it may stress the system a lot, but that doesn't mean it doesn't run the risk of failing at something else. This is why i've always perscribed to the above theory. If it's stable for what i use it for, then it's stable...period.

I'm sure you could get a task scheduler then cycle through Pi, 3dmark06, PCmark06, and your other favorite programs.

Leave it on when you sleep, then check the system logs the next day to see how it went.

Well sods law dictated that it wasnt stable at all, after posting that - and i've had to trim back the speed to 2700Mhz. 2800Mhz was fine - but try and run/encode an XviD and *poof* BSOD about IRQL_NOT_LESS_THAN_OR_EQUAL

And no more voltage will help - which is annoying. It could be that my 450watt ATX2.0 PSU (i have to have a 20 to 24-pin adapter) is on its way out - its a really heavy, noisy one anyway...