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Assembly And Overclocking

System Builder Marathon: $1,250 Mid-Range PC
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Assembling the system went smoothly and without much to talk about. Our sole irritation was that the Radeon 4850 X2 is a massive 11.25 inch behemoth––it is so huge, in fact, that it would not fit in the Cooler Master Centurion case (or not without some modifications).

To fit the beast in the Centurion, we had to remove the hard drive cage. Four screws later, the 4850 X2 was seated in the motherboard and good to go. Of course, we had to move the hard drive into one of the floppy drive bays but this was a minor nuisance at worst. It would have been more problematic with a two- or three-drive array, perhaps.

It turns out the 4850 X2 exhausts air out of the top of the card, which ended up fighting the Centurion case's side-panel cooler that was set at the factory as an air intake. We then reversed the fan so that it became an exhaust fan to help the 4850 X2 spit its heated air out of the case.

Other than this, we have no issues to report with the platform and hardware from an assembly point of view, which is a pleasant surprise considering that this is a relatively new chipset, motherboard, and CPU. Kudos to the hardware and driver teams.

Unfortunately, the Radeon 4850 X2 video card wasn’t quite as accommodating as the rest of the platform. First, it seemed Sapphire’s Radeon 4850 X2 was not recognized by any of the drivers on AMD’s Website. The card worked fine when we installed the driver off of the CD, but we were prevented from using the new Catalyst 8.12 driver suite. History has shown that AMD will support newer cards in time, but the 4850 isn’t exactly a spring chicken, and we would’ve liked to see the 8.12 drivers recognize the card.

Using slightly older drivers was a nuisance, but it wasn’t nearly as irritating as the inexplicable crashes we experienced with the card. At stock speeds when running graphics benchmarks, it would lock up, plain and simple. At first we suspected high temperatures but the 4850’s cooler was doing a fine job keeping the card under 60 degrees Celsius under load. Further experimentation showed us that the card would perform stably if the two GPUs were underclocked by 50 MHz, while our only thought was that we might have a bad apple.

Looking on the Web for similar experiences, it doesn’t look like this is a widespread issue with the 4850 X2. But while a 50 MHz underclock on the core probably won’t affect our benchmarks by more than a few percent points, it’s really going to hurt us when we overclock and try and bring the fight to last month’s 4870 X2 performance numbers.

In any case, we went forth on our overclocking mission hoping that the CPU would be more accommodating than the GPUs were.

Overclocking

This is my first time playing with the Core i7, so I have an opportunity to share some of my learning-curve experience with you folks.

Most of you probably know that the Core i7's frequency is determined by its multiplier multiplied by a base clock speed. The base clock works essentially like the front side bus (FSB) does when overclocking Core 2 CPUs and the i7 920 doesn't allow control of the multiplier. So overclocking an i7 is very similar to overclocking the Core 2 as you up the voltages a bit and raise the base clock (abbreviated BCLK).

Intel has implemented something called "overspeed protection" in its Core i7 models, which poses a small problem. The CPU will put a stop to things if it draws more than 130 W/100 amps. If you draw more when overclocking, the CPU will throttle back its multiplier and lower the clock speed. Ouch.

There are two ways to deal with this limitation. The first is to find a motherboard that has an option to disable overspeed protection. Intel's own boards have a CPU VR Current Limit Override option in the BIOS that turns overspeed off, and on the ASUS board we tested the option called "CPU TM Function." If your board supports a similar setting, you're in luck since you can then raise voltage as high as you like and overspeed protection should not kick in. The second way to deal with this limitation is to avoid it entirely. If we ensure that our CPU voltage is set low enough that it will never hit the 130 W limitation at 100 amps, we should be good to go. Now, 100 amps x 1.3 V = 130 W, so 1.3 V should be about the maximum setting you can use on the i7 920 without worrying about bumping into the overspeed-protection limitations. Since the stock voltage of the i7 920 is 1.2 V, this does give us some room to stretch our legs a bit.

We couldn't find an obvious overspeed-protection option in the Gigabyte BIOS, but in our case it didn't really matter since at 1.32 V, the CPU was overclocking to 3.7 GHz without the overspeed protection kicking in and lowering the multiplier. We did turn off Turbo Mode when overclocking because it constantly adjusted the multiplier and we preferred consistent performance.

In the end, heat limited us more than anything else. We settled on a final overclock of 3.7 GHz by setting our voltage to 1.32 V from the stock 1.2 V; we set the QPI/VTT voltage to 1.3 V from the stock 1.2 V; and we set the IOH Core voltage to 1.2 V from the stock 1.1 V.

One note about the IOH core voltage: when we tried to set it to 1.3 V, we experienced a hard crash when everything would lock up and the screen output would freeze. This is very odd, but when we backed up on the IOH Core voltage to 1.2 V, things were peachy.

We used two software utilities to record temperatures during our overclocking efforts. Speedfan reported a 42 degrees Celsius temp at idle and Realtemp indicated 52 degrees Celsius. The BIOS health monitor appeared to agree with Realtemp, which seemed very high for idle temps, even with the stock cooler.

The load temperatures reported by the Speedfan and Realtemp utilities were absolutely terrifying with the stock cooler. After a 1/2 hour Prime95 run, the temperatures plateaued as Speedfan reported 85 degrees Celsius, and Realtemp reported 95 degrees Celsius. (Chris: I can confirm--in my upcoming i7 920/Phenom II comparison, I'm also seeing the 920 peak at 85 degrees Celsius under load). Looking around on the Web, it seems that other folks are reporting high Core i7 temperatures as well. We experienced no stability problems with the machine at these temperatures so we decided to plod on, but we would certainly recommend a better cooler than the stock piece if you plan to put together an i7 machine for overclocking purposes.

For the Radeon 4850 HD X2, we did manage to overclock the memory from 993 MHz to 1,060 MHz even though the cores were unwilling to go anywhere. The 67 MHz increase wasn't great and probably won't make a difference in the benches, but it was better than nothing.

Now that we're armed with higher clocks, let's throw it down against last month's E8500 machine and its impressive 4+ GHz overclock.

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  • -4 Hide
    Hellcatm , December 30, 2008 7:36 AM
    Personally I'd get a cheaper processor and motherboard and go with a Gforce 280 video card. You can get a $180 processor and a $145 motherboard and the 280 card has PhysX built in which is really nice.
  • 6 Hide
    enewmen , December 30, 2008 7:57 AM
    I will hope to see how a high-clocked q9550/q9650 E0 will compare with a i7 920. The Motherboard and RAM will be cheaper. So, you can also get more RAM and faster RAM with the q9550 than the i7 920 with the same cash. Or the high-bandwidth/ lower total memory DDR3 tri-channel might actually do better?
    I don't think a i7 920 /w 3 gigs RAM will work as quickly as a q9550 @ 4.0Ghz with a 470mhz fsb and 4+ gigs RAM -even with quad-core supported apps.
    Anyway, I think the outcome will be hard to predict.
  • 9 Hide
    one-shot , December 30, 2008 9:03 AM
    I think the Q9550/i7 920 comparison would be very informative. I have been considering purchasing a Q9950 in the near future. Let's see it happen.
  • 9 Hide
    chriscusano , December 30, 2008 9:58 AM
    I agree with I'd agree with trying to run a comparison with the Q9550. Throwing in an nvidia card would also prove interesting.
  • 3 Hide
    pcgamer12 , December 30, 2008 10:08 AM
    Very good article. I just want to say that the Crucial 3GB triple-channel DDR3 1066 kit costs only $73.99; its price surprised me. Go Crucial! I'm definitely looking into a Crucial memory kit for my next upgrade or build, which might or might not be Core i7, depending how the price wars progress between nVidia and ATI (saying AMD still feels wierd to me when referring to video cards). I noticed how the budget had to "settle" for a 4850 X2 when they Core 2 Duo build had money for a 4870 X2. Hopefully, prices will go down faster, and soon.
  • 2 Hide
    Pei-chen , December 30, 2008 10:10 AM
    Page 2 - E8500 has 6MB L2 cache, not 4MB.
  • 5 Hide
    Anonymous , December 30, 2008 10:45 AM
    Yes, please try the next system with the Q9550! I would love to see how this processor compares again the new kid on the block. Of course this is the processor I have and also want to see what you get out of it. It would be nice if you chose another Gigabyte board as well to get a more apples to apples comparison with this month's build.
  • 6 Hide
    Huttfuzz , December 30, 2008 11:00 AM
    Yes we want to see Q9550 against Core i7 920. Both overclocked at the same speed. Let's say 3.8 or something like that.
  • 3 Hide
    JeanLuc , December 30, 2008 11:04 AM
    Good article, well done. At first I was a bit worried for the Core i7 was going to get humiliated against the higher clocked E8500 but you summary shows just how much progress has been made with developing software that can take advantage of multiple cores.

    The Supreme Commander: Forged Alliance benchmark was surprising out of all the games you tested I expected that game to be the one which showed off what quad cores can do for games. Perhaps you could add in GTA IV into your future benchmarks as that games seems to love quad cores?

    The temps were a little worrying but the Intel Stock cooler isn’t designed with overclocking in mind and you can pretty much guarantee a decent 3rd party cooler will slash those temps by a third.

    One last thing it might be an idea to compare your very first mid range build to your current mid range build, it would give the readers an idea as to how much more bang for buck we get now days.
  • 0 Hide
    kelfen , December 30, 2008 11:11 AM
    well 4850x2 there is only two in newegg 2gb and 1gb which not sure if ATI rly supported as far as drivers compared to its bigger brother
  • 1 Hide
    Anonymous , December 30, 2008 11:22 AM
    I read this and I suddenly start to cry ... you may have read before that figures in Euros are equal to figures in Dollars ... but things got worse and worse.

    The current prices in an average shop in Spain:

    Intel Core i7 920 : 293 EUR = 413 USD
    GIGABYTE GA-EX58-DS4 : 219 EUR = 308 USD
    Sapphire Radeon 4850 X2 2 GB : 349 EUR = 492 USD
    6 GB Patriot DDR3-1333 CL7 Kit : 259 EUR = 365 USD
  • -7 Hide
    kelfen , December 30, 2008 11:24 AM
    spain lol
  • 1 Hide
    Pei-chen , December 30, 2008 11:52 AM
    And yes, please include a GTA 4 benchmark. I got more FPS from overclock my C2D 700MHz than overclock my 9800GT 100Mhz.
  • 0 Hide
    bvbellomo , December 30, 2008 12:08 PM
    The Q9550 would be interesting because it would show how much gain is from the change from Dual to Quad core and how much is gain from the new i7 architecture. This comparison is very relevant to everyone buying/building a new quad core system right now, especially around this price range.

    What I would really like to see is the new i7s on the CPU charts.
  • 0 Hide
    cah027 , December 30, 2008 12:36 PM
    I think it would have been cool if you would have used two 512mb 4870's in crossfire instead of the 4850 X2. I think there would have been a different trade off in memory amount but I think the added speed of the i7 might have offset it nicely.
  • 0 Hide
    Anonymous , December 30, 2008 1:01 PM
    I guess core i7 is strictly suited for high end systems ($2000+), where the added costs of memory, mobo and cpu are justified. for low to mid range systems it is too much to bare.
  • 1 Hide
    trabello , December 30, 2008 1:28 PM
    In the next SBM we should watch the brand new GTX 295, keep it in mind, folks ;) 
  • -3 Hide
    jerreece , December 30, 2008 2:12 PM
    I'm kind of surprised that you folks chose a new i7 for a "Mid Level" system.

    You've upgraded the processor, but downgraded the video cards from last month.

    "Not really. The i7/4850 X2 still performs at about 80% of the level that the E8500/4870 X2 is managing to achieve."

    Of course this new system performs less than the November one.
  • 1 Hide
    Roland00 , December 30, 2008 2:23 PM
    I understand you keep Vista 32 to make it easier to compare to the previous systems, but in reality you should really upgrade to vista 64.

    You have a total of 3.5 gigs of memory to play with in vista 32. Since you only put in a graphic card with 2gigs of video memory that leaves 1.5 gigs of memory for normal applications and the OS. Anybody that reads these system builder marathons are going to put vista 64 on their computer if they are going to use vista.
  • 0 Hide
    terr281 , December 30, 2008 2:46 PM
    Your chart regarding the base and overclock settings of the Dec. pc on page 7 is inaccurate. (Ram and Graphics card.)
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