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Easy Multiplier Overclocking (Cont.)

How To: Overclocking Your AMD Processor
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Now that we've walked through the steps to overclocking the Phenom II X4 940, let’s take a look at the results attained with the other three CPUs.

The two other AM2+ processors will follow the same rules that the Phenom II does, except we take one extra step and enable Advanced Clock Calibration (ACC). ACC will only be available on a motherboard with AMD's SB750 southbridge, such as this 790GX-based ASUS platform we're using. It can be enabled within the BIOS or within AOD, but requires a reboot for the changes to take effect.

With the 45 nm Phenom II, it is better to just leave ACC disabled, since AMD claims that the feature's benefits are already baked in to its Phenom II silicon. But with the 65 nm K10 Phenom and Athlon processors, setting ACC to Auto, +2%, or +4% can often help stretch the maximum attainable core speeds of the chip: 

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max OC no voltage boostmax OC no voltage boost

Max MultiplierMax Multiplier

Max OCMax OC

The screen shots above show how our Phenom X4 9950 runs at 2.6 GHz with a 13x multiplier and CPU VID of 1.25 V. The memory frequency is crossed out, as it was set to DDR2-1066 and not the DDR2-800 used once overclocking began. The multiplier was raised to 15x for a 400 MHz overclock at stock voltage. Voltage was pushed to 1.45 V, ACC was enabled and set to Auto, +2%, and +4%, but Prime95 would only run for about 12-15 minutes. Interestingly, with ACC set to Auto, a 16.5x multiplier, and 1.425 V, the reference clock was raised all the way to 208 MHz, resulting in an even higher stable overclock. 

StockStock

max OC no voltage boostmax OC no voltage boost

Max OC no ACCMax OC no ACC

Max OCMax OC

Our Athlon X2 7750 has a stock core speed of 2,700 MHz and a CPU VID of 1.325 V. Without a voltage boost, we were able to bump the multiplier to 16x for a stable 3,200 MHz. The system was stable at 3,300 MHz with just a slight bump to 1.35 V. With ACC still disabled, Core VID was raised all the way to 1.45 V in .025 V increments, but the system was far from stable with a 17x multiplier. It even crashed prior to any torture testing. Setting ACC at all cores at +2%, we reached an hour of Prime95 stability at 1.425 V. This processor didn’t play nicely with voltages over 1.425 V, so the maximum stable easy overclock achieved was 3,417 MHz.  

The benefits attained through enabling ACC will, like overclocking on the whole, vary greatly from chip to chip. It’s a valuable tweak to have as an option and can take a serious amount of time to fine tune for each core. While we didn’t get a large boost from ACC with either of these two processors, take a look back at our 790GX introduction  for more information on ACC and the much larger impact it had for the Phenom X4 9850 used in that article. 

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Top Comments
  • 12 Hide
    xx12amanxx , February 20, 2009 6:27 AM
    It's nice to see articles about AMD cpu's once again! Just goes to show that Tom's is not biased but rather report's on current trend's and competetive product's that the consumer's enjoy!

Other Comments
  • 12 Hide
    xx12amanxx , February 20, 2009 6:27 AM
    It's nice to see articles about AMD cpu's once again! Just goes to show that Tom's is not biased but rather report's on current trend's and competetive product's that the consumer's enjoy!

  • 6 Hide
    Anonymous , February 20, 2009 6:34 AM
    Thanks for rev!
    Things i like to add are that not all CPU's are supported with AOD even having decent mobo, for example my 4850e + 780G. When overclocking NorthBrige you should really pay attention on it's temp, by simply touching it. Recently i overclocked my system by rising FSB and IGP. Looking at temps given by BIOS and some utilities everything seemed to be ok about 50c, but when touching pasivly cooled NB i couldn't hold my finger for second and heat was so great that even CPU got warmer! When i measured it with multimeter it was 85c idle! And i was wondering why on 3DMark i got blue screen... Problem was solved by adding fan in zone of NB.
    Anyway, moral for those who are willing to overclock is - don't relay on temp measurements given by some utilities. Sometimes it's worth double checking or u can burn something easy. :)  Good luck!
  • -6 Hide
    cruiseoveride , February 20, 2009 7:23 AM
    Intel is such a meany. Another wannabe monopoly like Microsoft.

  • -2 Hide
    curnel_D , February 20, 2009 8:36 AM
    AMD overdrive doesnt see my K8 proccessor as an AMD procc. Cute.
  • 2 Hide
    jhanschu , February 20, 2009 10:08 AM
    I realize that the price difference between the "black edition" and normal processors aren't that much, but I have been wondering how well the "vanilla" cpu's would oc. I've done some light searching for anyplace that's done this and haven't found anything other than people attempting to max out the BE's.
    Does anyone know what a good OC on say the X3 710 would be? It's about $40 cheaper than the 720BE and if it could even hit close to 3.0 I would consider it a decent buy.
  • 1 Hide
    DjEaZy , February 20, 2009 3:08 PM
    ... nice one... and for tha fun of it... would be nice to see a 'system build marathon' based on AMD CPU's...
  • 2 Hide
    roofus , February 20, 2009 3:37 PM
    xx12amanxxIt's nice to see articles about AMD cpu's once again! Just goes to show that Tom's is not biased but rather report's on current trend's and competetive product's that the consumer's enjoy!


    I do agree. I honestly don't think TH ever conducted a boycott of AMD. They just needed something worth saying and AMD finally gave them that. Until Phenom 2, they really had not earned recognition for a good year and a half. They didn't have bad products, but very forgettable ones.
  • 2 Hide
    sandmanwn , February 20, 2009 4:39 PM
    easily one of the best articles I've seen here in a long while.
  • 1 Hide
    iamlouie , February 20, 2009 4:53 PM
    It seems like this article was written specifically for me. I recently built a new PC and it has components used in this article and I've also never overclocked a PC before.

    Specs:
    ASUS M3A78-T
    AMD Athlon 64 X2 7750 Kuma 2.7GHz
    Patriot Extreme Performance SDRAM DDR2 800 (PC2 6400)
    GeForce 7600GT 256MB
    XIGMATEK HDT-S1283
    Antec 500w Earthwatts power supply

    My video card suits my current needs but if I upgrade to a 4870/4850, will I have any power issues if I follow this guide word for word considering my power supply is only 500w compared to the 650w the article uses?
  • 0 Hide
    deuce271 , February 20, 2009 5:13 PM
    iamlouieIt seems like this article was written specifically for me. I recently built a new PC and it has components used in this article and I've also never overclocked a PC before.Specs:ASUS M3A78-TAMD Athlon 64 X2 7750 Kuma 2.7GHzPatriot Extreme Performance SDRAM DDR2 800 (PC2 6400)GeForce 7600GT 256MBXIGMATEK HDT-S1283 Antec 500w Earthwatts power supplyMy video card suits my current needs but if I upgrade to a 4870/4850, will I have any power issues if I follow this guide word for word considering my power supply is only 500w compared to the 650w the article uses?



    A single 4850 and a dual core cpu around 3Ghz will be fine on your 500W PSU. If you had a cheap brand 500W PSU, I wouldn't risk it, but a 4850 should be fine for you.

    The 4870 probably would be fine too but you would want to look into that before purchasing/installing the card.
  • 1 Hide
    salem80 , February 20, 2009 7:09 PM
    Phenom II x3 reach 5Ghz on Ice now see
    http://www.tomshardware.co.uk/forum/page-258314_10_0.html
  • 0 Hide
    dimaf1985 , February 20, 2009 10:03 PM
    wow just in time for my upgrade to Phenom II. i know how to OC my K8, but i wasn't sure what the difference would be with a K10. thanks toms.
  • -2 Hide
    JohnMD1022 , February 21, 2009 12:54 AM
    What is the point of posting photos that cannot be read?

    It's as bad as the unreadable color combinations on the AMD website.
  • 0 Hide
    Silluete , February 21, 2009 1:34 AM
    yeah the photos quality very bad, btw i using ecs ECS A780GM-A Black and Atlon64 X2 6000+ why the AOD won't let me touch the OC bar?
  • 0 Hide
    pauldh , February 21, 2009 4:18 AM
    JohnMD1022What is the point of posting photos that cannot be read?It's as bad as the unreadable color combinations on the AMD website.

    Click on the pics to expand and they should be simple to read. ;) 
  • 0 Hide
    pauldh , February 21, 2009 4:22 AM
    RRRThanks for rev!Things i like to add are that not all CPU's are supported with AOD even having decent mobo, for example my 4850e + 780G. When overclocking NorthBrige you should really pay attention on it's temp, by simply touching it. Recently i overclocked my system by rising FSB and IGP. Looking at temps given by BIOS and some utilities everything seemed to be ok about 50c, but when touching pasivly cooled NB i couldn't hold my finger for second and heat was so great that even CPU got warmer! When i measured it with multimeter it was 85c idle! And i was wondering why on 3DMark i got blue screen... Problem was solved by adding fan in zone of NB. Anyway, moral for those who are willing to overclock is - don't relay on temp measurements given by some utilities. Sometimes it's worth double checking or u can burn something easy. Good luck!

    Yes, thanks for mentioning this about checking by touch or probe when raising NB VID and not relying on reported mobo temps for NB temps.
  • -1 Hide
    Anonymous , February 21, 2009 4:42 AM
    Someone please answer me.
    Whether there is any utility (AOD for AMD processors) which can work with intel processors?
    Also, can i overclock from windows if my BIOS doesn't support overclocking?
  • 1 Hide
    pauldh , February 21, 2009 4:47 AM
    jhanschuI realize that the price difference between the "black edition" and normal processors aren't that much, but I have been wondering how well the "vanilla" cpu's would oc. I've done some light searching for anyplace that's done this and haven't found anything other than people attempting to max out the BE's. Does anyone know what a good OC on say the X3 710 would be? It's about $40 cheaper than the 720BE and if it could even hit close to 3.0 I would consider it a decent buy.

    Initial Street Pricing has spaced the X3 710 and 720 apart, but if you look the X3 720 is right now down to $150 on Newegg making it a $30 difference. I’d like to get my hands on a X3 710 myself to test on the Asus M3A78-T. It has a CPU multi locked at 13, so your OC will depend on the reference clock your mobo can hit. I question how far beyond 3.3GHz, especially if considering the X3 710 for the $625 SBM build as we couldn’t pair it with too expensive a mobo, still keeping a nice GPU, and sticking to strict $625. With the right mobo, I’d hope for 3.4GHz or beyond(similar to X4 810), but I have not used one nor even seen anyone’s results, so that’s just a guess. Of course, the flexibility of the Black Edition would be easily worth the extra $30 IMO if not confined to that strict budget.
  • 2 Hide
    pauldh , February 21, 2009 5:07 AM
    iamlouieIt seems like this article was written specifically for me. I recently built a new PC and it has components used in this article and I've also never overclocked a PC before.Specs:ASUS M3A78-TAMD Athlon 64 X2 7750 Kuma 2.7GHzPatriot Extreme Performance SDRAM DDR2 800 (PC2 6400)GeForce 7600GT 256MBXIGMATEK HDT-S1283 Antec 500w Earthwatts power supplyMy video card suits my current needs but if I upgrade to a 4870/4850, will I have any power issues if I follow this guide word for word considering my power supply is only 500w compared to the 650w the article uses?

    I'll agree with Deuce that the Earthwatts 500W would have no problem for the HD 4850 upgrade. With 34A of 12V it should also handle the HD4870 just fine unless you are ridiculously loaded with drives & fans. If you look at the $750 International Challenge article you'll see I paired an OC'ed E8500 and HD 4850 with an Earthwatts 380W and had no issues at all. The last $625 SBM also used a 500W with 34A 12V paired with an HD 4870. I would have easily used the Earthwatts 500W on that system had it been cheaper at the time.
    Congrats on the system; it's very nice. I like the Asus mobo, the Kuma X2 7750 Black is sweet for such a low price, your cooler choice offers great performance and is quiet, the EA500 a solid PSU I use myself. If you want to game a 4850/4870 would do wonders for the system and both are priced right(in the USA anyway).
  • -1 Hide
    iamlouie , February 21, 2009 11:16 AM
    pauldhI'll agree with Deuce that the Earthwatts 500W would have no problem for the HD 4850 upgrade. With 34A of 12V it should also handle the HD4870 just fine unless you are ridiculously loaded with drives & fans. If you look at the $750 International Challenge article you'll see I paired an OC'ed E8500 and HD 4850 with an Earthwatts 380W and had no issues at all. The last $625 SBM also used a 500W with 34A 12V paired with an HD 4870. I would have easily used the Earthwatts 500W on that system had it been cheaper at the time. Congrats on the system; it's very nice. I like the Asus mobo, the Kuma X2 7750 Black is sweet for such a low price, your cooler choice offers great performance and is quiet, the EA500 a solid PSU I use myself. If you want to game a 4850/4870 would do wonders for the system and both are priced right(in the USA anyway).


    Thanks to you and deuce271 for the replies!
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