AMD has been real quiet on what exactly this does, but it does indeed help on overclocks for performance and underclocks for power savings as seen in a lot of reviews.

My question is, would there be a noticable difference between an ACC value of +2 and +12?

I don't really have anything to add, I just want to second the question here. I've seen sites OC with the new SB750, heck I've done it, but all I've done is turn ACC on, I don't know what the values do. I think I read some vague description of it, but I don't remember what it was.

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ASRock M3A785GMH/128M
Phenom II X4 925c2 @ 2.80GHz (95W)
OCZ Platinum PC3-1333 2x2GB 7-7-7-21
WD5000AADS
Raidmax RX-500AF
Check it out.

I think +6 is as far as I have tested. I found in a couple of tests that +4 rather than +2 on one of the cores helped complete 3DMark06 and Vantage at certain o/clock settings but +2 on all cores works most of the time with this system @ or above 3500Mhz. Maybe using certain setting +12 could be useful but I haven't found those settings as of yet. I would think that +2 to +12 would be a big change.

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AMD (one of the) be's @MHz varies- memory-varies by MB
790FX or 890FX may change at any time
1 ASUS 5970+2x5870's in CrossFireX, 3XEvga GTX 260's Tri-SLI
Maxtor 80GB (IDE) or some other drive
Windows 7 RC 32-bit/64-bit, sometimes some other OS
Swiftech Ultra water cooling (cpu only) cool water*
or Clockin Cooler chilled water (cold water) CPU only

i too am curious about ACC.
i havent messed with it at all, cant find that much info on it

Kazgirl, where are you at when we need you????


-dimwit-

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I don't suffer from insanity. I enjoy every minute of it.

Does this setting have to do with offset from nominal for the main oscillator on the mainboard, I have no idea.

With the devices I test, we have an output pin from the main oscillator, on that pin we measure the the main oscillator clock for the device. As a result, there is a setting that is used to compensate for the fact that not all oscillators run at exactly the same speed.

Makes me wonder if the ACC setting is used in a similar fashion.

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The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

Physics? Ha! This is clearly magic and devilry at work. Prepare firewood! We have witches to burn!


MODERATOR

Everytime I enable ACC my system will no longer post on boot. I have to reset the CMOS to get the setting cleared out every time. What am I doing wrong??

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The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

It means your motherboard manufacturer isn't fully supporting your cpu with the bios you are using. I had that issue when I first installed my 9950 but at least it wouldn't crash until Vista started. In a couple of weeks, MSI released a new bios for my board and ACC worked fine. I haven't seen setting information yet on a Phenom II, but for a 9850 or a 9950 everything I've seen and by experimenting myself indicates not to go over +2. A +4 setting is suggested for 9500 and 9600 Phenoms and seemed to work on my 9600 fairly well. Of course, I did kill the memory controller on that cpu when some G.Skill memory crashed and burned. I don't think it was ACC related though. Lately, I have been running auto on my 9950 when I backed it down to 3.0ghz with 1.296 volts and it's working fine.

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MSI DKA790GX Platinum
Phenom 9950BE o/c 3.0ghz-Sunbeam Core Contact Freezer
2 x GB G.Skill DDR2 1066mhz @ 5-5-5-15
Diamond Radeon 4890 o/c 950/1150
Antec True Power New 750-Antec Sonata Solo case
250gb Seagate SATA drive-300gb Seagate SATA drive
Vista Home Premium 32 bit

ACC isn't needed with the 940 at least that is what I have been reading. I turned mine off in the bios also. I did help my 9950 when it was installed in this motherboard though. Apparently the magic ACC worked on the Phenom I is included in the PhenomII so no motherboard bios ACC is needed or wanted at least for the M3A79-T Deluxe.

-------------------------
AMD (one of the) be's @MHz varies- memory-varies by MB
790FX or 890FX may change at any time
1 ASUS 5970+2x5870's in CrossFireX, 3XEvga GTX 260's Tri-SLI
Maxtor 80GB (IDE) or some other drive
Windows 7 RC 32-bit/64-bit, sometimes some other OS
Swiftech Ultra water cooling (cpu only) cool water*
or Clockin Cooler chilled water (cold water) CPU only

Good deal! Thank you so much for giving this your due diligence!

-------------------------
The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.

how do you enable aac?

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Antec 900
Processor: AMD 9950 @ 3.0ghz
Ram: 8GB Corsair Xtreme DDR2 PC2 1066
650 Watt Corsair PSU
1x Hitachi 320 Gb HDD
1x WD 500 GB HDD
MSI Nvidia 9600GT (OC'd to 725mhz)
(gddr3 to 2000mhz)
2x LG dvd burners
Vista Premium 64 bit

I looked through the manual for your motherboard and I didn't see the ACC option in the bios. It is in the CPU configuration section of the bios of my motherboard. You may need the AMD chipset in order to find the ACC option in your motherboard's bios. Based on the testing I have done using ACC it only helped at the extreme upper end of the overclocks say maybe to get the last 10-50Mhz to help complete a test at the highest overclock the system would handle (using the current settings). With air cooling the temps during the overclock may become a factor before ACC would help you anyway.

-------------------------
AMD (one of the) be's @MHz varies- memory-varies by MB
790FX or 890FX may change at any time
1 ASUS 5970+2x5870's in CrossFireX, 3XEvga GTX 260's Tri-SLI
Maxtor 80GB (IDE) or some other drive
Windows 7 RC 32-bit/64-bit, sometimes some other OS
Swiftech Ultra water cooling (cpu only) cool water*
or Clockin Cooler chilled water (cold water) CPU only

Your motherboard is based on an Nvidia chipset. Only motherboards with an AMD chipset using a 750 Southbridge support ACC.

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MSI DKA790GX Platinum
Phenom 9950BE o/c 3.0ghz-Sunbeam Core Contact Freezer
2 x GB G.Skill DDR2 1066mhz @ 5-5-5-15
Diamond Radeon 4890 o/c 950/1150
Antec True Power New 750-Antec Sonata Solo case
250gb Seagate SATA drive-300gb Seagate SATA drive
Vista Home Premium 32 bit

Apologies, but it's still not entirely clear to me what it does.
It is for over-overclocking? Like, you have your chip overclocked, and then use it to squeeze a few extra % out?
Or is it instead of overclocking? You overclock your chip less, and then use ACC to push it back up.

Also, can someone explain what particular/hybrid mode is, please? Does that just enable the feature?
Thank you.

As far as I know, with ACC enabled, you can get higher clocks at the same voltage stable.

http://www.anandtech.com/cpuch...owdoc.aspx?i=3360&p=4

without ACC: 2.8 GHz stable, with ACC 3.0GHz stable

I don't know what you mean by hybrid mode, sorry.

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Phenom II 940 @3.40GHz 1,35V|Xigmatek HDT-SD964|Foxconn A79A-S|4GB Kingston HyperX 1066 CL5 2.0V|Sapphire HD4830 512MB|Sharkoon Avenger|LC6600GP2 600W
http://www.sysprofile.de/id99196

My understanding is also that the Phenom II's do not need ACC enable, and I can confirm, when I enable it, my system gets more unstable than with it disabled, lol. has the opposite effect

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The opinions expressed above do not represent those of Advanced Micro Devices or any of their affiliates.