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Safe Overclock: 3.8 GHz (FSB1600)

How To: Get A 4 GHz Dual-Core For $120
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The next, most logical step is FSB1600, which equals the system speed being used by the Core 2 Extreme QX9770 (400 MHz base clock speed). Although the enthusiast systems run on the X48 chipset, the P45 can also support FSB1600 speeds easily, although Intel did not officially release the chipset for this speed. However, the plethora of motherboards being promoted as FSB1600-capable illustrate the existing overclocking margins.

We had to increase the CPU voltage from 1.35 V to 1.385 V to hit 3.8 GHz on FSB1600 (400 MHz base clock speed), which wasn’t a problem. However, the system wasn’t stable at first—Prime95 crashed after a few seconds of operation. We increased the microcontroller hub/northbridge voltage to 1.25 V to be sure it wouldn’t fail during overclocking, and we further increased the processor voltage to 1.405 V. This allowed us to operate the system at up to 3.9 GHz, although we decided to stick with 3.8 GHz to ensure reliability. Additional core clock speed of 100 MHz won’t deliver much extra performance, but it will increase the risk of system crashes.

Great Performance, Increased Power Consumption

We used the Core 2 Duo E7200 at 3.8 GHz core clock speed and FSB1600 system speed in our test labs for several days, and found it a rather quick workhorse. We benchmarked the processor at stock speed (2.53 GHz), at 3.4 GHz and at 3.8 GHz, and included the Core 2 Duo E8500 for reference.

The power level of the overclocked system wasn’t great, however, as the overclocked processor idle power went from only 91 W for the entire system to as much as 102 W at 3.8 GHz for the overclocked Core 2 Duo E7200. The peak power changed even more: while the system running the E7200 required only 121 W peak power, it went to 149 W at 3.4 GHz and as high as 170 W at 3.8 GHz. This represents a 40 percent increase in system power consumption. The same system running a Core 2 Duo E8500 showed peak power of only 134 W; it was outperformed by the overclocked E7200 by a considerable margin.

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  • 0 Hide
    Anonymous , 17 November 2008 23:13
    Why didnt you bench the processor at the same speed as the 8500 to make things nice and easy?...
  • 0 Hide
    graphicequaliser , 21 November 2008 02:00
    I have an E8500 overclocked to 3.8GHz using the 400MHz FSB and DDR2-800 Nanya dual channel memory running 1:1. It is the fastest ever and it barely gets warm. It is my home PC. I also have an office PC running an E7200 at stock speeds and that is nice and fast (quiet too). I must say Intel's new 45nm chips are really excellent vfm, fast and ecologically-friendly. Well done Intel! You can find my configs and benchmarks under the picture at http://www.jacobsm.com/index.htm#rngimg
  • 0 Hide
    Solitaire , 25 November 2008 01:33
    You moan about how lame the E5200 is then fail to even bench it to prove your point. You also forgot to say that quite a few people can't afford the extra ~€50 to buy a E7200 over a E5200, or that they'd probably have to spend a similar additional amount on an even better performance mobo to eke out the higher FSB needed to effectively OC a E7200.

    Yes, more FSB is good, but it costs money as the combination of a FSB1066 CPU and a low multiplier means you need a performance mobo that can run stable at FSB1600 to get the E7200 to a speed the high-mult, low-FSB E5200 can achieve at a measly 302MHz FSB (FSB1208 quad-pumped) - something even many cheapie boards can achieve (with FSB1333 compliance being considered the entry level more and more now).

    And I'm surprised that you need 1.40v+ to keep the E7200 stable at 3.8GHz - my E5200 is stable up to 3.75GHz at just 1.30v, and I'm nowhere near finished OCing it. The E5200 is based on low-binned silicon dies and thus is on average more power-hungry (and hot/wasteful), requiring relatively higher voltages to achieve the same speeds as the middle-binned E7XXX (which is in turn inferior to the high-bin E8XXX). Just as a comparison the Intel safety spec says voltages over 1.3625v are not at all good for a 45nm chip's health (although extreme cooling mitigates this somewhat)...
  • 0 Hide
    bobalazs , 25 April 2010 22:29
    The only thing that sucks about this processor is that it does not have virtualization.Otherwise, it's cheap, and easily overclockable.
  • 0 Hide
    bobalazs , 25 April 2010 22:32
    For proper overclock you would have to reduce the 9.5 multiplier to 9 or 8 as most motherboards have trouble with the half multi.