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How To: Get A 4 GHz Dual-Core For $120

How To: Get A 4 GHz Dual-Core For $120
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Despite the acceptance of overclocking by even the most prominent processor vendors, including AMD and Intel, tweaking and tuning your computer still means pushing it beyond its specifications, introducing potential risk to your system. The good news: that risk is relatively small, and falling processor prices make it increasingly attractive for performance enthusiasts to get high performance from low-cost processors. We recently found an excellent and affordable processor that lends itself to overclocking. Intel’s Core 2 Duo E7200 can operate at about 50 percent increased clock speed without much resistance on air cooling. This one’s for those of you who’ve been asking for realistic overclocks after all of our Overdrive coverage.

Core 2 Overclocks Well

Intel’s current generation of Core 2 processors overclocks extremely well. The dual-cores all operate from 2 GHz to 3.33 GHz and are manufactured on Intel’s modern 45 nm process, which offers a lot of headroom to reach faster clock speeds. Most Core 2 CPUs can be overclocked just by increasing the 266 MHz or 333 MHz bus speed (known as FSB1066 and FSB1333). Since the processor speed is a multiple of the bus speed, increasing the bus speed 20 percent means increasing the core clock speed 20 percent as well.

The only limitation is your hardware, but the limits can be extended by applying slightly higher voltages to the processor (or to the chipset on the motherboard). Intel’s current architecture for many Core 2 models provides overclocking margins in excess of 500 MHz for bus speed and 4 GHz or more for clock speed. The maximum reliable clock speed depends on the individual processor—every CPU is different, and one E7200 that hits 4 GHz doesn’t mean yours will go as high without additional coaxing in the form of voltage or cooling.

How to Overclock

Running a Core 2 Duo E8500 at a bus speed of 400 MHz instead of 333 MHz achieves approximately the same 20 percent increase and means overclocking from 3.16 GHz to 3.8 GHz. Most high-end mainstream motherboards will support this reliably; you may have to increase the processor core voltage slightly. But actually configuring those settings is very easy within the BIOS, which on most motherboards you can enter by pressing the Delete or F2 key just after powering on the system. Most BIOS versions offer a sub-menu where you can set the processor parameters.

System speed or bus speed is called FSB, which stands for front side bus, and the processor voltage item is called Vcore (voltage for the processor core). Unfortunately, there isn’t a single operating voltage anymore, but each processor has a voltage range in which it’s intended to operate. You’ll find information on the voltage range with Intel’s Processor Finder. Intel defines a maximum voltage of 1.45 V—don’t exceed this without proper cooling, and be sure you’re willing to risk processor damage. Generally, only hardcore users attempt this maneuver.

Ed.—Bear in mind also that scaling your front side bus speed up will affect the operating frequency of your memory as well. Most motherboards will "downshift" memory frequency automatically if it gets too high, but keep an eye out for clock speeds that exceed what your memory can do. If needed, manually reducing the ratio of FSB to memory can save your overclock at the expense of a little bandwidth.

What’s the Best Overclocking Processor?

Each processor maker has a large portfolio of dual- and quad-core processors,. History shows that going for the most advanced models will get you the best overclocking margins. In the case of Intel processors, this means going for a 45 nm Core 2 processor, or for an E7000 or E8000 product. To find the best option, check the Processor Finder for the S-Spec code for the newest stepping (stepping means “revision” in processor-industry lingo). The higher the letter and number, the newer the stepping—M0 is newer than B3, for example.

Going for the latest stepping typically doesn’t make a difference in performance, but the latest version implements all fixes and updates. Sometimes this results in slightly lower operating temperatures—or better overclocking margins.

Go Easy

We typically don’t recommend purchasing a $999 Core 2 Extreme processor for overclocking unless you have money to burn. You’ll get great performance, but your investment will be worth only a fraction of its original value after a few months. It’s better to buy an entry- or mid-level model based on the same technology and manufacturing process as the top model. We’ve tested the Pentium D 805, which overclocked from 2.66 GHz to 4.1 GHz and the Pentium Dual Core E2160, which we took from 1.8 to 3.2 GHz. Our latest recommendation offers more cache, better performance, lower power requirements, and up to 4 GHz for only $120.

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  • 10 Hide
    vitreoushumor , November 17, 2008 1:13 PM
    You're using an $80 ($62 at newegg) heatsink to cool your $120 processor so it performs marginally better than a stock clocked $190 processor. Is that really worth $8, especially if most E8500 retail processors can hit 3.8GHz on the stock cooler?

Other Comments
  • 1 Hide
    johnbilicki , November 17, 2008 9:29 AM
    Cache is your friend! In example on my moderately modified version of AWStats (web statics programmed in Perl) my socket 754 2.0 GHz 1MB single channel CPU chewed a 120MB access log in 15 seconds flat. My socket 939 2.2GHz 512KB cache CPU took a full minute. Keep in mind the socket 939 processor had a 200Mhz advantage over my socket 754 as well as dual-channel memory support. Both of those benefits had little if any positive effect on the final outcome.

    I'd recommend getting the cheapest next increment in cache which would be the E8200. It has 6MB cache instead of 3MB and is $160 which isn't a drastic increase.

    Of course more cache doesn't always increase performance. Everything tends to be subjective just like the individual processors.

    It would be nice to see an article stressing what types of programs benefit the most from cache. For some people that extra $40 is money well spent while others would see no benefit from spending the extra money.
  • 5 Hide
    slomo4sho , November 17, 2008 9:44 AM
    I guess a 40% increase in power consumption isn't too bad for a 50% increase in clock speeds, although at some point it would be more economical to go with the E8400 or E8500(especially if you live overseas where power costs are almost triple of that in the states).

    Thanks for the write-up.
  • 1 Hide
    jamesl , November 17, 2008 10:21 AM
    "Of course more cache doesn't always increase performance. Everything tends to be subjective just like the individual processors."

    http://www.xbitlabs.com/articles/cpu/display/core2duo-e7200_4.html#sect0
  • -7 Hide
    vider , November 17, 2008 10:21 AM
    N'of I know what go bût for ou next rît, thanks tom's :) 
  • 6 Hide
    slomo4sho , November 17, 2008 10:39 AM
    http://www.anandtech.com/casecoolingpsus/showdoc.aspx?i=3458

    I wish you provided data of a overclocked E8500 to 3.8GHz as well in your power consumption charts.

    In current market prices, the E7200 is about $70 cheaper than the E8500. So you pay roughly 60% more initially to step up to a E8500.

    If we are to assume that you will get at least 2.5 years of use out of the chip and that there is 25 watt power consumption difference between a E8500 @ 3.8GHz and a E7200 @ 3.8 GHz(on average), then if an individual would keep his PC on 24/7 would actually pay an additional $70 in power charges in the 2.5 year span. At this point it would be better go with the E8500 as the extra cache would provide better performance and there is no difference in the overall price of the system over the average lifespan.

    I hope to see full power consumption data in future articles.

  • 0 Hide
    Homeboy2 , November 17, 2008 11:50 AM
    I only paid 150 for my e8500
  • 0 Hide
    johnbilicki , November 17, 2008 11:53 AM
    Thanks jamesl, that's a nice comparison across the board. At about 10% performance I'd spend the extra money...not everyone would granted.
  • 0 Hide
    Pei-chen , November 17, 2008 12:06 PM
    Did the voltage changed when OCed to 3.4GHz. I know you said no put the power consumption doesn't make sense. 15w more for a 283MHz increase in speed and half the cache of E8500?
  • 2 Hide
    Pei-chen , November 17, 2008 12:13 PM
    Did the voltage changed when overclocked to 3.4GHz? I know you said no but the power consumption increase doesn't make sense at both idle and loaded. 10w more at the same clock and half the cache at idle and 15w more with a 233Mhz clock increase and half the cache. It is as if E7200 are inherently less efficient.
  • -5 Hide
    Alien_959 , November 17, 2008 12:18 PM
    Clock speed is enough to compensate for the 3 Mb cache missing, and I think that 3 Mb is quite sufficient for gaming and general task. 3.8 Ghz CPU for 120$, faster that most E8xxx, that’s excellent.Clock speed is enough to compensate for the 3 Mb cache missing, and I think that 3 Mb is quite sufficient for gaming and general task. 3.8 Ghz CPU for 120$, faster that most E8xxx, that’s excellClock speed is enough to compensate for the 3 Mb cache missing, and I think that 3 Mb is quite sufficient for gaming and general task. 3.8 Ghz CPU for 120$, faster that most E8xxx, that’s excellent.
  • 7 Hide
    hairycat101 , November 17, 2008 12:20 PM
    I would have been intersted in seeing both the E7200 and the E8XXX clocked at exactly the same speed to for these tests too. That would have shown how much cache is or isn't important for the individual tests performed. This kind of leaves us guessing...
  • 3 Hide
    trinix , November 17, 2008 12:29 PM
    @john you are comparing 2 different designs from AMD (who uses another system and has other benefits from cache than intel)and based on that you say everyone should get more cache.

    Cache is important, don't get me wrong, but there are some problems with the 8200. The 8200 is harder to overclock to begin with, it's already at 1333 for example.

    It really depends on what you need it for and if the money would be wasted or not. The apps described are mostly games and zip. Important for a lot of people, but what difference would it be of use to get a better cpu lesser gpu or the other way around. I think this will help people on budget get a good cpu and gpu.

    Cache is still very important for the Core2 design. Now let's see if it's as important for the i7.
  • 2 Hide
    trinix , November 17, 2008 12:37 PM
    you can compare the results based on fps too. Crysis needs about 300 mhz more to compensate for the loss of cache.

    UT3 is very slightly ahead at 300 mhz advantage

    World in Conflict needs more then 300 mhz to compensate for the 3mb loss.

    If you follow the link a bit higher, you will find a page describing it will be about 5% overall increase in performance, with games up to 10% increase.

    So if you have the money, the premium price for cache is worth it. But if you are on a budget, don't worry about the small loss.
  • 6 Hide
    clownbaby , November 17, 2008 12:39 PM
    so, the title should probably be "How To: Get a 3.8ghz Dual Core for $120". Are the titles written before the articles here?
  • 0 Hide
    BSMonitor , November 17, 2008 12:42 PM
    Speaking of more E7#00 to come. Newegg already has a 10.5 multiplier version.. E7400 at 2.8GHz for only $145. Bumping FSB just to 1333 already gives you 3.5 GHz!!
  • 1 Hide
    slomo4sho , November 17, 2008 12:45 PM
    Pei-chenDid the voltage changed when overclocked to 3.4GHz? I know you said no but the power consumption increase doesn't make sense at both idle and loaded. 10w more at the same clock and half the cache at idle and 15w more with a 233Mhz clock increase and half the cache. It is as if E7200 are inherently less efficient.



    Quote:

    An increase in processor operating frequency not only increases system performance, but also increases the processor power dissipation. The relationship between frequency and power is generalized in the following equation: P = CFV^2 (where P = power, C = capacitance, V = voltage, F = frequency). From this equation, it is evident that power increases linearly with frequency and with the square of voltage.


    I hope this answers your question!
  • 10 Hide
    vitreoushumor , November 17, 2008 1:13 PM
    You're using an $80 ($62 at newegg) heatsink to cool your $120 processor so it performs marginally better than a stock clocked $190 processor. Is that really worth $8, especially if most E8500 retail processors can hit 3.8GHz on the stock cooler?

  • 5 Hide
    hairycat101 , November 17, 2008 1:41 PM
    vitreoushumorYou're using an $80 ($62 at newegg) heatsink to cool your $120 processor so it performs marginally better than a stock clocked $190 processor. Is that really worth $8, especially if most E8500 retail processors can hit 3.8GHz on the stock cooler?


    VERY GOOD POINT. I had a PD805 super overclocked and thought I was cool for while before I did the math and realized I could have had a better CPU/cooler combo for cheaper if I had not had to spend so much extra $$$ on the darn cooler.
  • 1 Hide
    x11nt4 , November 17, 2008 1:49 PM
    E8500 is $188.99 with free shipping at newegg. This has been their price for at least a week. Not $210+. I don't know what websites you people writing these articles look at, but I always check newegg first for all prices. I'll pay the extra $60 for double the cache.
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