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Advanced Overclocking

How To: Overclocking Your AMD Processor
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The term "advanced" is being used loosely here, in contrast to the easier methods covered thus far, as a way to cover any overclocking through the BIOS and cranking up the reference clock. The success of your overclock will constitute the sum of how well all your components can be pushed, and to find the limit of each, we will take things one step at a time. It is not mandatory to follow all these steps, but finding the maximum for each of your components can help achieve a higher overclock altogether, as well as helping you understand why a limit is reached.

As mentioned, some overclockers prefer to strictly stick to BIOS-based tweaking, while others will find that AOD remains a valuable time-saving tool for testing, without the need to constantly reboot. These settings can then be manually set and further tweaked in the BIOS as needed. Which method you choose is a matter of preference as both have their advantages and disadvantages.

Again, it’s a good idea to disable the Cool’n’Quiet and C1E power-saving features, spread spectrum, and any automatic CPU fan control that keeps the fan from running at a 100% duty cycle. We also had CPU Tweak and Virtualization turned off for part of the tests, but didn’t see an impact either way with our processors. Later on, these features could be activated again as needed and you could then see if there is any impact on system performance or the stability of your overclock. 

Finding Maximum Bus Speed

We now move on to the techniques that owners of non-Black Edition chips will need to follow in order to overclock (without the ability to increase the multiplier). Our first step is to find the maximum bus speed (reference clock) that our motherboard and CPU are capable of accomodating. One thing you will quickly notice is the variations in naming of some of our frequencies and multipliers that we previously mentioned. For instance, the reference clock in AOD is referred to as the "Bus Speed in CPU-Z" and "FSB Frequency" in this BIOS:

If you are going to do all of your overclocking in the BIOS, then you will want to reduce the CPU multiplier, the northbridge multiplier, the HyperTransport multiplier, and the memory frequency. In our BIOS, lowering the northbridge multiplier automatically limits the available HyperTransport link frequencies to those at or below the same resulting northbridge frequency. The CPU multiplier can be left alone and instead lowered in AOD, adding the ability to later raise CPU core speed without rebooting. 

With our Phenom X4 9950, we selected a CPU multiplier of 8x from within AOD, knowing that even with a 300 MHz bus speed we would still be under the processor's stock core speed. From there, we raised the bus speed from its default to 220 MHz, and then in increments of 10 MHz all the way to 260 MHz. Going beyond 260 MHz, we took it 5 MHz at a time, reaching a maximum of 290 MHz. It is not necessary to take it all the way until instability is found, and we could have easily quit at 275 MHz knowing it would be highly unlikely that we would be running at this high of an northbridge clock speed. Since we overclocked the reference clock from within AOD, we ran the AOD stability test for a few minutes with each increase to be sure it was stable. If doing this from the BIOS, just the ability to boot into Windows is probably a good enough test, in combination with some final stability testing at the higher bus speeds to be sure they are stable.

Finding Maximum CPU speed

Since we already multiplier-overclocked in AOD, we know the maximum CPU multiplier and also now know the maximum bus speed we can use. With a Black Edition processor, we can experiment with any combination within these limits that allows us to maximize our other frequencies, such as northbridge speed, HyperTransport link speed, and memory frequency. Right now we will continue on as if the multiplier was locked at 13x, as we find the maximum CPU speed by raising the bus speed in increments of up to 5 MHz at a time.

Whether in the BIOS or in AOD, we bring the bus speed back to 200 MHz, and set the multiplier back to 13x, resulting in our stock 2,600 MHz. Note that the northbridge multiplier is still 4, resulting in an 800 MHz speed, while the HyperTransport link speed is also still 800 MHz and the memory is still running at 200 MHz (DDR2-400). We follow the same procedure of increasing the bus speed in increments and by stability testing and making small increases in CPU VID as needed as we finally reach our maximum CPU speed after enabling ACC.

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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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