what exactly does Advanced Clock Calibration do?

[dukeman]

i have activated it on my GA-MS790GP-UD4h to see if i could activate the 4th core. that did not work.
now there is a bunch of changes in the ACC, but what benifit is there is changing it from auto to say +6%?
i set it to +2% but i could not increase my oc at all. i could not find a good explanation on what it does so if anyone can please let us know.

[Lsdmeasap]

Re: what exactly does Advanced Clock Calibration do?

Shhh, it is a AMD Secret that they do not want to talk about......

What BIOS are you using? Just wondering why you could not enable the fourth core, as the few I have checked for users only had core enable/disable settings in the ACC Section of the BIOS.

Not sure what exactly it can do, but I read it can help with overclocking. There is a tool posted here, not sure if this is board specific or not though >>
iXBT Labs - AMD OverDrive Advanced Clock Calibration Requirements

Here is some more info on ACC I found for you >>
AnandTech: AMD's SB750: Enabling Higher Phenom Overclocks?

SB750 and Advanced Clock Calibration unlocks higher Phenom frequencies | NordicHardware

How does Advance Clock Calibration work? - XtremeSystems Forums

[dukeman]

Re: what exactly does Advanced Clock Calibration do?

thanks for the info. it was interesting but did not help explain it.

i am using the newest bios for the board. i will see if there is something i am missing as to why i can not active the 4th core.

[Lsdmeasap]

Re: what exactly does Advanced Clock Calibration do?

Sorry I cannot provide more info, from what I found online it seems AMD has not released very much (NONE) info on these features and I do not use AMD myself so I am at a real loss trying to provide you with anymore information then what I could find posted above.

Let me know if you find anything else with better info, that way I can let others know if asked in the future

[wayout44]

Re: what exactly does Advanced Clock Calibration do?

i am using the newest bios for the board.

This is exactly why as AMD is closing this loophole with BIOS updates.

To activate that other core you'll have to use an older BIOS version that did support this feature (if this particular mainboard came with 1) but be warned as there are X3's runnin' around that do indeed hav a totally stuffed core on then & nothing you can do will get the extra core working.

[Lsdmeasap]

Re: what exactly does Advanced Clock Calibration do?

I do know in most of the BIOS's I have opened to check if this feature is user accesible for members all I have found is the Core 0-3 enable/disable features, nothing like mentioned above.

So wayout44 may be correct and you may just need to use a older BIOS to find the feature you are wanting to try as it seems it may be changed in the version you have.

Actually, just checked BIOS for you, this is what/all I see for ACC options, looks to be only BIOS Default is disabled, but you can enable and select options per core (You should be able to, once you enable, select "Auto, All Cores, or Per Core) >>

GA-MA790GP-UD4H BIOS F2h



Do you do not see those options in MIT, or do you see something else?

[stackisan]

Re: what exactly does Advanced Clock Calibration do?

Ok, correction to my post.
I have searched for it a bit and I have found some following info that may be of use:

"There is no impact on performance, no change of voltages or frequencies, it just allows for more and higher overclocking. Anandtech reports that the new BIOS of coming motherboards with the SB750 southbridge has a much wider range of settings for the Advanced Clock Calibration (ACC). In the past this function could be set in increments of 1 between -2 up to 0. With the board they've used they could set ACC to anything between -12 to +12. Negative values unlocks lower power operations while higher values unlocks better overclocking.

Exactly what it does hasn't been revealed, but it somehow seems to loosen the strains a bit and allow the cores to be pushed further in either direction. It should be emphasized that this is a Phenom-exclusive feature. You will not gain anything with your Athlon series processors. We should also mention that AMD will use this feature with its coming 45nm processors, which means that the prior reports of decent overclocking with the Deneb core, may be understated." - mikeyk365

"This will NOT help your Phenom II chip (it has ACC integrated).
This is for the first Phenom chips. Do NOT use ACC or it'll make your OC unstable (ironic but true.)" - dzalias