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Overclocking Intel's Core 2 Quad Q8200

Guide: Overclocking AMD And Intel CPUs On A Budget
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Intel’s value-priced Core 2 Quad Q8200 uses two of the same processor dice as the Pentium E5200, at a lower clock speed and a higher front side bus clock. The combination of moderate CPU frequency and higher FSB also requires a lower CPU multiplier, and Intel designs these so that the multiplier cannot be increased.

Intel typically uses a low FSB on mainstream processors to modulate performance and expand compatibility, so we’re not certain why the company chose FSB-1333 for its cheapest quad-core models. We do, however, know that many overclockers specifically select low-cost processors for the higher multiplier that typically accompanies a lower bus speed, so that its use of FSB-1333 for the Q8000-series has all but prevented its adoption amongst enthusiasts. After looking at the far higher prices of Q9000-series processors, we returned resolute to get big gains from the Q8200, viewing its lower multiplier as a challenge.

Unfortunately, the Q8200 would barely budge beyond its original 2.33 GHz frequency, regardless of how much voltage we applied to its core, reaching the same 2.5 GHz overclocked speed at core voltage settings from stock to 1.45 volts. The problem, it seems, is that FSB-1333 is almost the limit for these cores at stock FSB voltage.

Dual-die processors of this design use the front side bus for both CPU-to-chipset and die-to-die communication, and increasing the CPU FSB beyond 354 MHz (2.5 GHz CPU clock) would require an increase of the “VTT FSB Voltage” setting seen in the second screenshot below.

Our research showed that CPU FSB voltage had the same practical limit as core voltage: 1.45 volts peak and “something less” under load for continuous long-term use. As with the core voltage of the E5200, we chose 1.40 volts as a target voltage for Q8200’s FSB. We were then able to increase the FSB to 384 MHz, but the resulting 15% overclock is barely worth the risk and effort.

We really wanted to reach at least the next “Intel standard” FSB clock of 400 MHz, or FSB-1600, but getting there required far more “VTT FSB Voltage” than we can safely recommend. Further research into other far-more-successful Q8200 overclocks revealed that those units were actually cream-of-the-crop “Q8200S” models.

The CPU cores certainly wouldn’t need a full 1.40 volts at so low an overclock, so we began back-tracking. While “VTT FSB Voltage” remained at 1.40 volts for a stable 384 MHz FSB, we were able to drop the “CPU Voltage” setting to 1.30 volts. Anything less resulted in an eventual crash under Prime95 v25.8 build 4.

With the chipset’s maximum memory clock rate of twice the CPU FSB clock, the fastest selectable memory clock of 768 MHz provided a data rate of DDR3-1536. As with the E5200, we then began stability tests using Memtest86+ v1.70 at progressively lower DRAM latency settings until the best stable timings of 6-6-5-16 were determined.

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  • 3 Hide
    tacoslave , July 20, 2009 6:38 AM
    i like these "how to" articles but i still want to see the rest of the twkr article you promised us (quad crossfire 4890's) *sigh* a man can dream can't he?
  • 0 Hide
    snakeeater_za , July 20, 2009 7:20 AM
    Surely people on a budget (like me) would prefer their e5200 to last longer than a 'few months or hopefully a yr to 3?' i know i will upgrade prob in a year or so, so a yr would be fine, but a few months? Pfffft. my proc vid is 1.225 and for 3.33ghz i need a vcore of 1.385 in bios which at idle is 1.36ish. So although im nowhere near 4 at least i wont suffer from electromigration and have to fork out for a new cpu! Just my 2 cents
  • -2 Hide
    snakeeater_za , July 20, 2009 7:22 AM
    Thats obviousl 4ghz not vcore lol
  • 6 Hide
    Crashman , July 20, 2009 7:35 AM
    snakeeater_zaSurely people on a budget (like me) would prefer their e5200 to last longer than a 'few months or hopefully a yr to 3?' i know i will upgrade prob in a year or so, so a yr would be fine, but a few months? Pfffft. my proc vid is 1.225 and for 3.33ghz i need a vcore of 1.385 in bios which at idle is 1.36ish. So although im nowhere near 4 at least i wont suffer from electromigration and have to fork out for a new cpu! Just my 2 cents


    It's all a game of averages. Tom's Hardware hasn't accidently killed a processor by overclocking it in a while, though I'm sure a couple editors have intentionally done so to find the voltage limit. The problem is, once again, you can only look at averages.

    3 months continuous use at 1.45 volts caused an E8500 to lose its OC stability. It had to be clocked down to become stable again, and lost much of its voltage tolerance. It wasn't destroyed however.

    1.40 volts should be significantly safer than 1.45 volts, but until a few people report on how long their cores lasted at 1.40 volts its impossible to tell "how much safer", that is, how much longer it will last. All that's known is that it should last "significantly" longer, but whether that's 4 months (33% longer) or 30 months (10x longer) is the unanswerable question.
  • 0 Hide
    astrodudepsu , July 20, 2009 8:30 AM
    Good show mate.

    I would have liked to see combined charts as a conclusion but that's a minor criticism.

    I'm just wondering what the 'next-gen' E5200 (i.e. the intel people's OC'er) will turn out to be? Some flavor of i5 I assume, but who knows.
  • 0 Hide
    Anonymous , July 20, 2009 9:52 AM
    how is it that im running my q8200 at 3.04ghz stable at 1.25v? weird
  • 6 Hide
    JeanLuc , July 20, 2009 11:43 AM
    Link

    "Intel’s value-priced Core 2 Quad Q8200 uses two of the same processor dice as the Pentium E5200....."

    I don't know why you choose the Q8200 it's a notoriously bad overclocking chip, if you wanted a budget Intel Quad core that had room for overclocking you should have bought the Q6700/Q6600.
  • 0 Hide
    Anonymous , July 20, 2009 12:20 PM
    ”Motherboard MSI P45 Diamond LGA-1366, P45/ICH10R, BIOS 1.5 (10/10/2009)”

    MSI P45 Diamond is not LGA1366, but LGA775. LGA1366 is for Core i7 processors only, LGA1156 is for Core i5 and i7 (only dual channel DDR3-1333/1066). LGA775 is the old socket, for Celeron D, Celeron 4xx, Pentium Dual Core, Pentium 4, Core 2 Duo, Core 2 Quad.
  • 2 Hide
    da bahstid , July 20, 2009 1:05 PM
    No games? Like...none at all? Does anybody even overclock for reasons other than games?

    Otherwise, pretty good article. Though perhaps a better choice for the Intel quad would have been a 9550...I thought they were under $250 by now. Same time, I guess the Q8200 does seem to be a more difficult overclocker...Intel may have intended this to be the case so as not to gut sales of their Q9000 series. And readers may as well know before jumping on a Q8200 thinking it'll overclock like an E5200.
  • 1 Hide
    freak77power , July 20, 2009 1:15 PM
    I agree. Q6700 will reach 3.6Ghz with no problems.
  • 6 Hide
    Anonymous , July 20, 2009 1:24 PM
    It's nice to see a Tom's article that doesn't intentionally low-ball their AMD OC, I'm sick of seeing 3.6ghz PhenomII OCs when we all know they can do better. They could've picked a better Intel quad though, and I think the Intel dual-core OC may be a tad extreme, that's not going to last for daily use at 4.1ghz.

    PS: Synthetic benchmarks should be outlawed until they fairly and accurately give an indication of real-world performance ;) 
  • 5 Hide
    Anonymous , July 20, 2009 1:49 PM
    Awesome12345: What has virtualization to do with overclocking? How many normal users(or even gamers) even use virtualization? Hell, most people probably won't even need it for Windows7 compatibility mode, except for enterprise users. Why not get a 955BE, the 945BE is hardly worth it since it's barely cheaper, why on earth would you recommend the non-BE? That is easily one of the most worthless comments to ever be left for an article...
  • 0 Hide
    awaken688 , July 20, 2009 1:52 PM
    I definitely have to agree with the comments about the poor choice of the 8200. I am one the shoppers this article is referring to and I did not even consider that chip. The Q9550 is $220 right now, so it really is the chip I am looking to purchase. I completely disagree with Awesome12345 though. As an inexperienced OCer, if I am going to go AMD, I am going to get a BE because it offers an easier solution. I also would have like to see a comparison at the end of the 4 chips performance side by side. Not a bad article though minus the worthless test of the Q8200.
  • 0 Hide
    Sihastru , July 20, 2009 2:32 PM
    Q8200 is cheaper, I give you that, but lack of cache, lack of VT, lack of deeper power states... the Q9550 (now only E0 should be on the market) is a far better choice, and it overclocks very well (3.4GHz without any effort at all, 1600 FSB + 800+ DDR2).

    Even so, you must have a dud, since Q8200 should overclock much more then what was achieved for the purpose of the article.

    E5200 is indeed the "new Celeron". A very good cheap chip, if you get it to at least 3.33GHz (1066 FSB + 1066 DDR2). I totally agree with this choice.

    But why did you go with DDR3? It's double the price of DDR2. In real life, if I have to choose between screaming-fast DDR3, or double the amount of that in DDR2... my personal preference is more RAM, even if slower RAM.

    So Q9550 + DDR2 could make the list, at least price-wise. With a little OC, it would be the king of this... let's call it roundup. Some may argue that the 955BE is, but I have my favorites.
  • -1 Hide
    KyleSTL , July 20, 2009 2:47 PM
    Why the exclusion of the Athlon II X2 250? It seems like it would be a perfect candidate for this article. And why did you include the $215 top-of-the-line AMD quad for a 'budget' overclocking article? Wouldn't a Phenom II X4 810 ($140) be a better analogue for the Q8200 ($160)? That way they'd be in the same price class, and they'd both be cut-down quads. Either that or take the 955 against the 9550 ($220), and they'd both be in the same price class and be fully-functioning dies.
  • 0 Hide
    blackened144 , July 20, 2009 2:47 PM
    orangethinkerhow is it that im running my q8200 at 3.04ghz stable at 1.25v? weird

    You got lucky.
  • 0 Hide
    rmc779 , July 20, 2009 3:09 PM
    A very well written guide. Bravo! It would have been interesting from the AMD side of things to test the bus speed overclock versus the multiplier overclock, finding the right balance and achieving a slightly better overclock overall with a mix of the two. I would have also liked to have seen if you had success unlocking the 2 extra cores on the X2 550 with the ACC.
  • 2 Hide
    Shadow703793 , July 20, 2009 3:30 PM
    Acording to Intel data sheets:

    1.45v is the ABSOLUTE MAX voltage for 45nm.
    1.5v is the ABSOLUTE MAX for 65nm

    Absolute Max is defined as "the point where actual damage to the CPU can occur."

    For more info: http://www.overclock.net/intel-cpus/374005-45nm-vcore-discussion.html
  • 0 Hide
    cadder , July 20, 2009 3:33 PM
    I was a budget shopper and I picked the Q9400 when I found it on sale earlier this year at Microcenter. It has proven very willing to overclock. I was thinking about a Q6600 but didn't really want to go that way because of the additional heat output.
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