Overclocking

Without increasing the core voltage on the 975, and using the retail cooler the highest stable overclock I was able to achieve was 3.73GHz:

Boosting core voltage by 16% I was able to hit 4.13GHz with the retail air cooler, but I could not get the system fully stable at any higher frequencies:

Gary was able to squeeze a 24/7 stable 4.4GHz out of his 975 on aftermarket air cooling with the EVGA X58 Classified and Gigabyte EX58-Extreme motherboards at 1.4V Core Vid, 1.375V VTT, 1.62V VDimm, and memory set to 7-8-7-20 at DDR3-1704 (new OCZ Blade PC17000). However, he admitted that if the retail Core i7-975 chips clock anything like the ES samples we were provided with that buying one would be a huge waste of money (actually his exact words were quite explicit but not printable). All of his retail D0 stepping Core i7-920 processors are easily hitting 4.4GHz~4.6GHz on high-end air coolers when installed in a variety of X58 motherboards. We have a retail Core i7-975 arriving later this week and will provide an update in the near future. As is always the case with overclocking: your mileage may vary.

Processor Highest Overclock (Stock Voltage) Highest Overclock (Overvolted) % Increase over stock
AMD Phenom II X4 955 3.8GHz 3.9GHz 22%
Intel Core i7 975 3.73GHz 4.13GHz 24%

With relatively similar transistor counts, similar starting clock speeds, it's wonderful to see that AMD is able to offer virtually identical overclocking headroom to Intel's flagship Core i7 in a 64-bit operating system.

Power Consumption Final Words
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  • silver250 - Friday, June 05, 2009 - link

    Maybe I missed it but last time I saw a review with the Phenom II CPU's they ran better with DDR3, all the boards for AMD listed are only DDR2 boards.
    So whats the deal? Or did I just miss a reason somewhere in other reviews?
    Reply
  • Tunnah - Thursday, June 04, 2009 - link

    would it be possible at all to get the power usage stats of the overclocked version ? A while ago I was reading an article (not sure if here or elsewhere) and it gave the power usage per overclock step and was a great way of working out where to find the balance of power usage vs overclocking amount. Also I'd love to see the power this beast sucks up at 4.6ghz ha Reply
  • tygrus - Thursday, June 04, 2009 - link

    Are you able to measure the CPU clock freq while running the benchmarks to see the affect of the Turbo mode. Labelling as 3.2GHz when it could actually be 3.46GHz.

    Can we also see results with the Intel Turbo On & Off ?

    Does Intel use core activity to determine Turbo limits or does the on-die temperature sensor allow using higher speeds at any time ?
    Intel claimed a bit of both, but it seems very pre-set (1core max, 2core max, 4core max). Can it be overridden ?

    How hot can the case temp be before the CPU is prevented from using higher speeds ?

    How much activity on other cores will prevent the fastest setting of single core task ?
    Reply
  • Hrel - Wednesday, June 03, 2009 - link

    This article is kind of pointless beyond page 1 just cause you don't include ANY of the processors that used to be the best bang for the buck. Where's the E6600? the E8400? E6420?? the E7650??? Q6600? Seriously, showing us performance for new CPU's is pointless if you're not going to include the processors that sold the best in the past. I mean seriously, the E8400 is STILL the best bang for the buck around for many people and you didn't even include that... sad, just sad. Reply
  • Gary Key - Wednesday, June 03, 2009 - link

    You can compare any of those processors to the 975 using our Bench tool - http://www.anandtech.com/bench/default.aspx?b=2">http://www.anandtech.com/bench/default.aspx?b=2 . :) Reply
  • lpcap - Wednesday, June 03, 2009 - link

    I think for the world's most powerful laptop with the Core i7 975 go to:

    http://www.lpc-digital.com/store/3302695/product/c...">http://www.lpc-digital.com/store/3302695/product/c...

    Reply
  • aigomorla - Wednesday, June 03, 2009 - link

    :)

    I dont have anything bad to say about it.

    Monster overclocker, im doing about 4.4ghz with 1.35vcore with full stability.

    When i showed the 975 off a couple of months ago on the cpu and overclocking section, i told everyone the D0's were gonna be HOT.
    Reply
  • Fulle - Wednesday, June 03, 2009 - link

    Interesting... most 920s only can OC to about 4GHz at that voltage... even with the D0 stepping. Either you got lucky with your chip, or the 975 isn't as bad as I thought. Reply
  • Fulle - Wednesday, June 03, 2009 - link

    Its fortunate for AMD that the vast majority of the games out there are NOT multithreaded, like FarCry 2... and for the majority of games out currently, they don't even scale with CPUs beyond 3 cores... which is evident if you look at the Phenom II X3 720's performance in Anand's benchies.

    It cracks me up to see some enthusiasts bashing Lynnfield. All things considered, the Lynnfield 2.8GHz CPU with HT will be the one to have for the best gaming frame rates. It has excellent 2 core performance with turbo mode, which will allow for top FPS in most games, and for those that are highly threaded, Graphics bottlenecks considered, it'll hang in pretty darn close to the i7s. Its almost as if Intel designed the chip specifically for hardcore gamers.

    This 975/950 business seems lazy, however. Intel doesn't even try when AMD falls too far behind.
    Reply
  • lifeblood - Wednesday, June 03, 2009 - link

    "Intel really has no other external motivation to push for higher frequency parts, so we only see a bare minimum increase in specs here."

    If AMD fails the we will very quickly return to the days of overpriced and underpowered Pentium trash. When Intel has no competition they quit trying.
    Reply

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