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Overclocking: Core i7 Vs. Phenom II

Overclocking: Core i7 Vs. Phenom II
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This match-up needs no introduction—but I’m going to throw one down anyway.

It’s no secret that Intel has dominated our performance tests over the past year. First, its Core 2 Duos at 45 nm gave enthusiasts a great platform for aggressive, yet relatively safe overclocking. The company’s Core 2 Quads cost quite a bit more, but they managed to deliver smoking speeds in the applications optimized for multi-threaded execution.

The recent Core i7 launch further cemented Intel’s position as the performance champion. Its Core i7 965 Extreme, clocked at 3.2 GHz, demonstrated gains straight across the board versus its outgoing flagship, the Core 2 Extreme QX9770. And the Core i7 920, Intel’s sub-$300 entry-level model running at 2.66 GHz, seems to have little trouble reaching up to 4 GHz on air cooling.

There was once a time when Intel didn’t handle its technology shifts as smoothly. As recently as the Pentium 4 Prescott core (OK, that was a while back), Intel struggled to maintain an advantage against AMD’s Athlon 64. But now, with the marketing of its "tick-tock" approach to rolling out lithography advancements and micro-architecture tweaks, things have certainly turned around. How is AMD expected to compete?

Core i7 920 and Phenom II X4 940 go head-to-headCore i7 920 and Phenom II X4 940 go head-to-head

Up until now, AMD has relied on the loosely-translated term "value" to keep in the game. On its own, the Phenom X4-series is a moderate performer. AMD knows this, and has priced the chip more competitively than Intel’s quad-core offerings to attract attention. However, the Phenom hasn’t had to exist alone in an ecosystem backed by third-party vendors. It’s instead complemented by AMD’s own chipsets, mainly the 790GX and 790FX. Of course, those platforms extend comprehensive CrossFire support for its own graphics cards, which have been capturing hearts since mid-2008.

Combined, AMD’s processors, chipsets, and GPUs have fared better than any one of those components would have alone. Thus, we’d consider the company’s efforts to emphasize its Spider platform—the cumulative result of all three puzzle pieces—a success.

AMD Needs Something New

In light of a new competitive challenge—Intel’s Core i7—AMD is revamping its Spider platform with a new processor and the addition of software able to tie all of the hardware together. As you no doubt already know from reading Bert’s story, this latest effort is called Dragon.

But we’re not here to rehash the details of Phenom II. Rather, in light of significant enhancements to the CPU architecture’s overclocking capabilities (and indeed, confirmation from AMD that all of the "magic" that went into its ACC [Advanced Clock Calibration] technology is now baked into Phenom II), we’re eager to compare the value of AMD’s fastest 45 nm chip to Intel’s entry-level Core i7 920—the one most enthusiasts would be likely to eye as an overclocking contender.

In the pages that follow, we’ll describe how each platform was overclocked, just how hot each system got, how much they cost, how well they perform at their top speeds, and, ultimately, which should be on the short list for your next upgrade.

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  • 17 Hide
    bernardv , January 12, 2009 7:23 AM
    This Phenom II overclock is very very far from optimal. Here are some points:
    1. 790FX board should be used, FX is the top end chipset.
    2. Ph2 doesn't support ACC, check the forums where skilled people got this CPU beyond 4GHz on air, they know what they were doing.
    3. If you're doing bench you should try to get an optimal RAM speed as well. Your RAM was running 30% below stock 1066!!! You must raise core do better.
  • 14 Hide
    cangelini , January 12, 2009 5:41 AM
    Uncle,
    With the Black Edition, that's really the value there. You want to use the multiplier for a clean, easy overclock. Once you've found your ceiling, use the reference clock to fine-tune the setup.
  • 13 Hide
    jtnstnt , January 12, 2009 6:17 AM
    I'm curious about the heatsink selection on the Phenom II. I looked up the Ajigo MF091 and it didn't look too impressive. While the Intel system gets the Thermalright 120mm True extreme. Whats up with that?
Other Comments
  • 0 Hide
    Roffey123 , January 12, 2009 5:00 AM
    At last a P2/i7 comparison to shut the people whining for one up. In all I think its a fair comparison - although I am disappointed that AMD's OC potential wasn't as good as they made it out to be. But as all overclockers know - not all chips are the same or have the same OC potential.

    The 3DS Max benchmark was puzzling as well, considering that i7 has 8 threads at its disposal. Do you guys have any idea as to why the AMD beat the i7 in that test; despite having only half as many threads?
  • 0 Hide
    unclefester , January 12, 2009 5:17 AM
    I thought it funny they use an ATI card on the Intel board (not that it makes a difference).
    Would have liked to see what the PII can gain or not gain by using the FSB not just the multiplier.
    Didn't see anything about memory timings either. As most PII OC's have been done at @880MHz.
    Overall a decent review.
    So Ford vs Chevy goes on.
  • -1 Hide
    apache_lives , January 12, 2009 5:37 AM
    I would love to see a high end overclocked Core 2 Quad 9 series in the tests here to see a price comparison - cheaper and already established platform etc.

    Also note that i7 platform should also feel more alive and responsive (un-benchmarkable) thanks to high memory bandwidths and more threads to balance things out like the P4C's and CL2 Dual Channel DDR1 - reguardless if it performed lower then the AMD A64's at the time it felt more responsive!

    Intel also has that more solid platform to back that CPU and options for Crossfire AND SLi so its more the premium option, but that cheaper AMD setup is too close to the i7 for my liking - a few shifts in prices and models should show an interesting result in the new few weeks.

    AM3 should be interesting, higher headroom + lower power etc (like 939 to AM2).
  • 14 Hide
    cangelini , January 12, 2009 5:41 AM
    Uncle,
    With the Black Edition, that's really the value there. You want to use the multiplier for a clean, easy overclock. Once you've found your ceiling, use the reference clock to fine-tune the setup.
  • -4 Hide
    vekere , January 12, 2009 5:42 AM
    I hear AMD is going to hire Sylar to look at the new Core i7 processor so this year we will have an answer.
  • 1 Hide
    kschoche , January 12, 2009 5:51 AM
    The WINRAR tests are so close to exactly half the time on the Intel chip compared to the AMD chip that I'd love to see how the results show up if you turn off hyperthreading, not that its a particularly meaningful result, but would be cool to look at still.
  • 13 Hide
    jtnstnt , January 12, 2009 6:17 AM
    I'm curious about the heatsink selection on the Phenom II. I looked up the Ajigo MF091 and it didn't look too impressive. While the Intel system gets the Thermalright 120mm True extreme. Whats up with that?
  • -5 Hide
    jtnstnt , January 12, 2009 6:18 AM
    Please explain.
  • 6 Hide
    apache_lives , January 12, 2009 6:38 AM
    jtnstntI'm curious about the heatsink selection on the Phenom II. I looked up the Ajigo MF091 and it didn't look too impressive. While the Intel system gets the Thermalright 120mm True extreme. Whats up with that?


    Heh very good point there, although it depends on wether the limits of the OC was architectural or thermal
  • 0 Hide
    jtnstnt , January 12, 2009 6:44 AM
    I was wondering because i didn't see an explanation in the article.
  • 3 Hide
    cangelini , January 12, 2009 7:09 AM
    jtnstntI'm curious about the heatsink selection on the Phenom II. I looked up the Ajigo MF091 and it didn't look too impressive. While the Intel system gets the Thermalright 120mm True extreme. Whats up with that?


    The Ajigo sports a copper base, four heat pipes, and an aluminum fin array. You're right--it's not a particularly spectacular heatsink, though it was the best Phenom II-compatible cooler in the lab. As a result, I made it a point to mention that stepping up to a better cooler might have yielded better overclocking, but would also erode some of AMD's price advantage as well.

    Heatsink aside, after talking to a number of colleagues from other sites at this year's CES, it sounds like the overclocks here are indeed representative of what others were able to do, even using different heatsinks. I'll look into getting more in the way of air cooling and hope for better results.
  • 17 Hide
    bernardv , January 12, 2009 7:23 AM
    This Phenom II overclock is very very far from optimal. Here are some points:
    1. 790FX board should be used, FX is the top end chipset.
    2. Ph2 doesn't support ACC, check the forums where skilled people got this CPU beyond 4GHz on air, they know what they were doing.
    3. If you're doing bench you should try to get an optimal RAM speed as well. Your RAM was running 30% below stock 1066!!! You must raise core do better.
  • -1 Hide
    arkadi , January 12, 2009 7:27 AM
    jtnstntI'm curious about the heatsink selection on the Phenom II. I looked up the Ajigo MF091 and it didn't look too impressive. While the Intel system gets the Thermalright 120mm True extreme. Whats up with that?

    P2 did go more than 60c, that what the article said any way. So i don't think it meter
  • 0 Hide
    falchard , January 12, 2009 8:01 AM
    I think you got the wrong end of the silicon with the chip. Anandtech was able to reach a stable 3.9 GHz with 1.52 volts.
  • 6 Hide
    cangelini , January 12, 2009 8:24 AM
    bernardv

    Bernard, 790GX is actually a newer platform than 790FX, and the only way stepping *back* to that one could have made a difference would have been if we were testing multiple graphics cards, in which case the chipset's PCI Express connectivity would have benefited it.

    Re: ACC--not sure if you were aware, but the enhancements rolled into ACC that made the Phenom a better overclocker are *already* rolled into Phenom II. Therefore, it doesn't need to support ACC since those capabilities are in-hardware.

    Re: RAM speed, we're using DDR2-1066. Per this page, that is the maximum official supported spec for the AM2+ version of the chip. Not sure if you mis-read that we were using DDR2-800, perhaps.

    All the best!
  • 6 Hide
    cangelini , January 12, 2009 8:26 AM
    falchardI think you got the wrong end of the silicon with the chip. Anandtech was able to reach a stable 3.9 GHz with 1.52 volts.


    And our own German lab was able to run 3.8 GHz at 1.55V and even boot at 4 GHz. And there's the variability of overclocking for ya. Everyone's experience is going to be different, and I can assure you that an extra 100-200 MHz would not change the tide of this comparison.
  • 2 Hide
    eodeo , January 12, 2009 8:32 AM
    Could you please disclose what are you testing in Max 9, maybe even share the scene so we could also test it? By your own scoring, i920 @ 3.8ghz in this test is slower than c2q 6600 @ 2.4ghz. I know something whent wrong, but I dont know what.
  • 2 Hide
    cangelini , January 12, 2009 8:38 AM
    eodeoCould you please disclose what are you testing in Max 9, maybe even share the scene so we could also test it? By your own scoring, i920 @ 3.8ghz in this test is slower than c2q 6600 @ 2.4ghz. I know something whent wrong, but I dont know what.


    Sure! From the Test Setup page (page 4) of this story:
    Version: 9.0, Rendering Dragon Image at 1920x1080 (HDTV)

    In essence, this is a single image being rendered out at 1920x1080. If you email me, I'd be happy to send along the source data (cangelini at bestofmedia dot com).
  • 0 Hide
    nashville , January 12, 2009 8:39 AM
    hey, in your ph2 review, power consumption on i7 was measured from 12v rail. i read uncore/cache dont get power from 12v rail, is this correct. if it is, will affect your measurements?
  • 0 Hide
    eodeo , January 12, 2009 8:53 AM
    Thanks for the quick response Chris! Will do.
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