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Optimizing Your Phenom II Overclock For Efficiency

Optimizing Your Phenom II Overclock For Efficiency
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Overclocking is and has been the number one tool for enthusiasts to increase system performance without incurring additional cost. Ever since motherboard manufacturers (and even the processor vendors themselves) started taking this market segment seriously, there have been features and products that allow all types of users--be they beginners or hardcore folks--to overclock their processors comfortably.

But how far should you go? Efficiency has become almost equally important to performance, and it is no secret that power consumption skyrockets at highly overclocked speeds when you start turning up voltage in the name of stability.

Phenom Versus Core 2

Difficult times began for AMD when Intel launched the Core 2 processor family in 2006. The Core 2 Duo was far superior to the Athlon 64 X2, and the Phenom quad-core CPU, which was launched in late 2007, could not beat the four-core, Core 2 Quad despite its theoretically superior architecture based on a monolithic design. We spent some time on a core-by-core analysis of all popular AMD models and found that the Phenom's Stars architecture was indeed an important step forward, though by no means a leap. AMD added Phenom X3 triple-core processors in early 2008, which helped the firm to stay competitive in the mainstream through price cuts. The portfolio was good, and AMD made sure that all products kept providing a nice bang for the buck, but Intel simply happened to be better in performance and efficiency.

AMD’s Phenom II Comeback

The Phenom II is AMD’s current top-of-the-line product, which finally moved AMD into a competitive position, thanks to the modern 45 nm DSL SOI manufacturing process. Idle power came way down and clock speeds could be increased up to a level that puts the Phenom II almost head-to-head with Intel’s Core 2 Quad processors. Unfortunately, Intel had already moved on to its next-generation, the Core i7, and has maintained the performance and efficiency crown since. Still, Phenom II typically offers similar performance at comparable price points, and the Socket AM2+ or AM3 platforms (DDR2 or DDR3) are usually more affordable than Intel’s 4-series chipset flotilla.

Which Is The Perfect Clock Speed for Phenom?

We used the current flagchip Phenom II X4 940 and ran it at various clock speeds, both underclocked and overclocked, to determine the clock speed at which the architecture delivers the best ratio between performance and power consumption.

Display 40 Comments.
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  • 0 Hide
    MAD4AMD , April 3, 2009 6:32 AM
    Great article! As always, Tom's showing another point of view for handling your hardware. And, yeah, Fusion works Bigtime! Better performance guaranteed.
  • 3 Hide
    ravenware , April 3, 2009 7:29 AM
    Good article, I have always been curious about how effective certain clock increases would actually be; especially for locked AMD cpus as you have to retard the ram frequency to get the core clock up higher which may result in a bottleneck.
  • 3 Hide
    wilsonkf , April 3, 2009 8:03 AM
    Useful article.

    About the higher-than-spec voltage applied - however, it is not recommand to set higher that safety limit (recommanded by AMD) voltage AND CnQ enabled together - the CPU could become much less overclockable after a short period, due to damage by switching voltage up and down from unsafe voltage.
  • 2 Hide
    Anonymous , April 3, 2009 8:20 AM
    Useful article for amd users. We are waiting like this article for core i7 cpus too.
  • 0 Hide
    Xajel , April 3, 2009 9:01 AM
    Well I'm already running my Phenom II 940 at 3.6, but I'm doing this with a mix of lower multiplier than 18 and slightly higher HTT clock, I'm running at 17.5x206=3605, ofcourse @ 1.4v.. I think it's a good idea to try the same overclocking speed but with the higher HTT clock, as this will increase the performance a little ( RAM will be overclocked too ).. it will be harder I know but it may worth the try...
  • -2 Hide
    neiroatopelcc , April 3, 2009 9:23 AM
    ehh "But how far should you go? Efficiency has become almost equally important to performance," efficiency is more like the opposite of performance with overclockers really!
    It's pointles to even consider efficiency as an overclocker! It's a bit like trying to tune a H2 for economy instead of torque or high rev horsepower .... you shouldn't have picked a H2 in the first place if efficiency is a concern.
    Power saving features for when systems aren't doing anything are welcome, but anything else is imo irrelevant.
  • 1 Hide
    Lozil , April 3, 2009 9:55 AM
    Indeed a Nice article after a Much time on Tomshardware, Straight and Up to the point in describing about the benefits of Overclocking..
  • 0 Hide
    Slobogob , April 3, 2009 10:27 AM
    Indeed a nice article. What i don't really "get" is why a Jetway mainboard was used? I can't even find a retailer in europe that has it on sale...
  • 1 Hide
    Onus , April 3, 2009 11:50 AM
    Hey Chris, thanks for getting the site's metadata updated. The charts became visible while I was reading this article.
    Neiroatopelcc has a point, but Fusion should address that. Striving for performance does not mean striving for waste, it means ignoring it. Well, I don't think anyone would argue that ignorance is a good thing. People will be able to OC to the teeth when they need it, but still be efficient when they don't.
  • 0 Hide
    shabodah , April 3, 2009 1:02 PM
    Great Overclocking article, but how about an underclocking article for the HTPC crowd? I'm kinda curious how much power different Phenom IIs use between 800 mhz & 2 ghz.
  • 1 Hide
    salsoolo , April 3, 2009 2:15 PM
    i still cant understand why does the i7 965 is 4x expensive than 940 ?
  • 4 Hide
    haricotvert , April 3, 2009 3:06 PM
    Salsooloi still cant understand why does the i7 965 is 4x expensive than 940 ?


    Because bragging rights are important to people with small genitalia, and they don't mind paying for that privilege.
  • 0 Hide
    IzzyCraft , April 3, 2009 3:21 PM
    haricotvertBecause bragging rights are important to people with small genitalia, and they don't mind paying for that privilege.

    Not everyone likes to oc? although i don't get why you would go 965 over 920 unless that kind of money meant little difference to you.
  • 0 Hide
    Anonymous , April 3, 2009 3:46 PM
    what is fun about all this coments is that despite all things you say
    im from argentina and this OC does not exist here jajaja
    and in addition we have the devaluation of our money and it cost to us almost 4 times what costs you anything
    example here a core 2 duo e8400 costs 800 pesos ... that is 220 dolars + -
    and i presume that even that in where you live isnt the real cost... instead much lower

    great page toms hardware by the way... the only thing is that everything is so expensive that i can only see the things but dont have it jajaja
  • 0 Hide
    tomich , April 3, 2009 6:42 PM
    yeah, ariel is right.. im from Argentina too.. as a computer technician i've seen a lot of monsters (super mega cooled I7's super mega overclocked Phenom's) but is not normal. i was thinkin on buying a system like this one (i cant afford a 1100 Watts PSU so i will go for something like 600 to 750W) and with that money me and my girlfriend live 3 months(including taxes). jejeje (no display included in the prize 'coz i already have a monitor).. I can't find anything that sounds similar to "Jetway" here.. so maybe i'll go for a MSI mother.. But i still have doubts as for the cooling.. What cooling solution was used in this article? stock cooler? the on ei see in the picture looks like a zalman or something like that.. can anyone answer that for me?..
    Thanks in advance
    Tom
  • 0 Hide
    hannibal , April 3, 2009 7:14 PM
    I agree, this seems to be an usefull article. But as was said in the above, could it be possible to see an article where that "sweet point" 3.6 Ghz would be achieved using different HTT clock? Is it really worth of it? How it affects the power consumption? Maybe a very little, but it would be nice to see!
    You all ready have proven that 3.6 GHz is the sweet point with normal HTT clocks, can the situation be different with different HTT settings? Or is it too much relative to the individual CPU you hapens to have?

    All is all this was interesting article to read! Keep it up!
  • 1 Hide
    dimaf1985 , April 3, 2009 8:50 PM
    Very nice article
    I was considering buying something a little more fancy than my OCZ Vanquisher so that i could go above 1.4v, but apparently there's no point, so thank you for saving me ~$100CDN.

    There are still some unresolved questions here. Why a Jetway mobo with a 790GX chipset? Something with a 790FX would have made more sense. Why would you leave CNQ on during overclocking? The first thing every OC guide will tell you is to TURN CNQ OFF. Also, how much does power consumption/temperature increase as NB frequency goes up? i.e. if you increase the reference clock, rather than the multi, the NB freq. goes up. How does that impact stability/power consumption/temperature?

    Still some mysteries here, but a nice article nonetheless.
  • 0 Hide
    coopchennick , April 3, 2009 10:00 PM
    To Chris or someone,
    I dont know if the other users are experiencing this but every few pages I click through on this site, especially during the articles, I get a message from my antivirus alerting me of a virus from a file when im loading a new page. I click "Deny" each time and all seems well.

    Virus: HEUR:Trojan.Script.Iframer
    File: http://ad.trafficmp.com/a/js?plid=10637

    Im using Firefox, Windows 7 build 7000, and Kaspersky for AV
  • 0 Hide
    cangelini , April 3, 2009 10:38 PM
    Coop--let me report this and see what happens. The malware issue we saw before was solved. I sincerely hope this isn't something new. Thanks for the heads-up!
  • 3 Hide
    Anonymous , April 3, 2009 11:20 PM
    This article is exactly how i overclock. Default voltage max stable, and then i back it off a little bit, or ill do a tiny increase in voltage but no more.

    Anything more then that are for 2 reason:

    1) Bragging rights
    2) People who don't care about the cost of their computer parts.

    If you have money to buy the latest and greatest every time it comes out and are changing hardware every 6 months, by all means push the chip to the limit and throw the voltage up, who cares if it frys.

    But its kinda funny when you see someone on a budget pushing their hardware with massive voltage increases ets, its just dumb if you cant afford to fry it.
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