+/-1% ACC...I know which cores are bad, which should I set it to?

[soccerballtux]

So cores 1 and 2 on my X3-720BE I can get to 3.7Ghz. Core 3 is the flakiest and I can't get it past 3.5Ghz. Core 4 is better, but still flaky. Prime95'ing higher than 3.5ghz, no matter the voltage, causes my computer to BSOD and reboot.

What setting should I set for cores 3 and 4? Currently they're set to auto-- but I don't image the motherboard can _actually_ adjust it on the fly.

 

[Plimogz]

First off, you should know that a lot of people have said that there is no benefit from using ACC with Phenom2. (except core unlocking of course, which is arguably a cooler feature than ACC ever was back when it "just" allowed 200-300MHz more overclock on mediocre Agena chips)

Beyond that, I personally have had some success clearing up instability on a non-unlocked 720BE -- you can either unlock or tweak ACC, not both -- by messing around with the +/-%. (edit: now that I think about it, I guess you actually can tweak ACC and Unlock... I'm not sure what I thought you couldn't.. Is it that you cannot apply ACC on a per-core basis with the Hybrid firmware which unlocks? anyway, I digress)
When I was playing around with it I just experimented with lots of values around the 0% mark (i.e. -4%, -2%, 0%, +2%, +4%) if I recall correctly I had some success with +4%...

Link to what I'd posted here at the time.

Some information that I've come across in the meantime, which spells out very clearly the AMD approved version of "how to use ACC to your advantage", goes on to say that +% values should help in attaining higher overclocks (or rather stabilizing a high overclock) and -% values are meant to help with a slightly unstable undervolt.

Finally, in case you haven't found this out the hard way already, be wary of anything beyond +6% or -6%; setting values too far out of spec will probably result in a no-POST situation which will require a CMOS clear.

 

[BD231]

ACC effects every chip differently so its up to you to find the settings that help your individual chip best; starting with negative value's.

 

[soccerballtux]

First off, you should know that a lot of people have said that there is no benefit from using ACC with Phenom2. (except core unlocking of course, which is arguably a cooler feature than ACC ever was back when it "just" allowed 200-300MHz more overclock on mediocre Agena chips)

Beyond that, I personally have had some success clearing up instability on a non-unlocked 720BE -- you can either unlock or tweak ACC, not both -- by messing around with the +/-%. (edit: now that I think about it, I guess you actually can tweak ACC and Unlock... I'm not sure what I thought you couldn't.. Is it that you cannot apply ACC on a per-core basis with the Hybrid firmware which unlocks? anyway, I digress)
When I was playing around with it I just experimented with lots of values around the 0% mark (i.e. -4%, -2%, 0%, +2%, +4%) if I recall correctly I had some success with +4%...

Link to what I'd posted here at the time.

Some information that I've come across in the meantime, which spells out very clearly the AMD approved version of "how to use ACC to your advantage", goes on to say that +% values should help in attaining higher overclocks (or rather stabilizing a high overclock) and -% values are meant to help with a slightly unstable undervolt.

Finally, in case you haven't found this out the hard way already, be wary of anything beyond +6% or -6%; setting values too far out of spec will probably result in a no-POST situation which will require a CMOS clear.

Thanks a lot for your post, I'll take a look at it. Very helpful.