iXBT Labs - Computer Hardware in Detail






Intel Core 2 eXtreme QX6850: Store Is No Sore

Even though Intel is an incontestable leader in the segment of top-end desktop x86 processors, and even though single-socket quad-core solutions for this price range are offered only by Intel so far, this manufacturer continues to please users who are ready to pay any money for ultimate performance with newer and faster CPUs. Today we are going to review another champion: Intel Core 2 eXtreme QX6850. It's even faster than the previous Intel's favourite, to say nothing of the last but one. It has a higher core clock, of course, and a higher FSB clock of 1333 MHz (QP). As a result, our testbed went euphoric and its results rose as high as the sky. :) Jokes aside, it's a top solution, what else can we say. It will hardly be affordable to many users. They can just admire the test results and feel the inexorable pace of the technical progress that leads us to bright future, when such processors are called Celerons. :)

Hardware and Software

Testbed configurations

CPU Motherboard Memory Video
Core 2 eXtreme QX6700
ASUS P5B Deluxe
Corsair CM2X1024-6400C4
GeForce 8800 GTX
Core 2 eXtreme X6800
ASUS P5B Deluxe
Corsair CM2X1024-6400C4
GeForce 8800 GTX
Core 2 eXtreme QX6850
ASUS P5B Deluxe
Corsair CM2X1024-6400C4
GeForce 8800 GTX
Athlon 64 X2 6000+
ASUS M2N32-SLI Deluxe
Corsair CM2X1024-6400C4
GeForce 8800 GTX
  • Memory: 2 x 1024 MB
  • HDD: Samsung HD401LJ (SATA)
  • Cooler for Athlon 64 X2 6000+: boxed
  • Cooler for Core 2 eXtreme: Zalman CNPS9700 NT
  • PSU: Cooler Master RS-A00-EMBA
CPU Core 2 eXtreme QX6700 Core 2 eXtreme X6800 Core 2 eXtreme QX6850 Athlon 64 X2 6000+
Process Technology, nm
Core Clock, GHz
Number of Cores
L2 Cache*, KB
FSB clock**, MHz
1066 (QP)
1066 (QP)
1333 (QP)
2x800 (DDR2)
Typical thermal emission***
130 W
130 W
130 W
125 W
Virtualization Technology

* - "2 x ..." means per core;
** - for AMD processors this is memory controller bus clock rate;
*** - measured differently for Intel and AMD processors; impossible to compare directly.


  1. Windows XP Professional x64 edition SP1
  2. 3ds max 9 x64 edition
  3. Maya 8.5 x64 edition
  4. Lightwave 3D 9 x64 edition
  5. MATLAB R2006a ( x64 edition
  6. Pro/ENGINEER Wildfire 2.0
  7. SolidWorks 2005
  8. Photoshop CS2 (9.0)
  9. Visual Studio 2005 Professional
  10. Apache HTTP Server 2.2.4
  11. CPU RightMark 2005 Lite (1.3) x64 edition
  12. WinRAR 3.62
  13. 7-Zip 4.42 x64 edition
  14. FineReader 8.0 Professional
  15. LAME 3.97
  16. Monkey Audio 4.01
  17. OGG Encoder 2.83
  18. Windows Media Encoder 9 x64 edition
  19. Canopus ProCoder 2.01.30
  20. DivX 6.4
  21. Windows Media Video VCM 9
  22. x264 v.604
  23. XviD 1.1.2
  24. F.E.A.R. 1.08
  25. Half-Life 2 1.0
  26. Quake 4 1.3
  27. Call of Duty 2 1.2
  28. Serious Sam 2 2.07
  29. Supreme Commander 1.0.3220


Essential foreword to charts

Our test method has two peculiarities of data representation: (1) all data types are reduced to one - integer relative score (performance of a given processor relative to that of Intel Core 2 Duo E4300, given its performance is 100 points), and (2) detailed results are published in this Microsoft Excel table, while the article contains only summary charts by benchmark classes. We will nevertheless focus your attention on detailed results, when needed.

3D Modeling and Rendering

If we have a look at detailed test results, we'll see that the four cores do not help in all operations except rendering, they are even interfering with performance (both QX processors are outperformed by the X6800). But owing to the huge advantage in rendering speed (this process can be distributed between cores almost perfectly) the total score of quad-core processors is still much higher.


To all appearances, QX6850 gains an advantage owing to a higher core clock rate plus a faster bus (you cannot explain this victory only by the clock rate), not because of additional two cores (or QX6700 would have outperformed X6800).

Digital Photo Processing

The most popular operations and filters in Adobe Photoshop cope well with distributing the load between two or four cores. It's a rare example of a popular program that is ready for quad-core processors even now.


Despite the official support for multithreaded operation, MS Visual Studio 2005 compiler failed to use four cores effectively: the advantage of QX6850 over X6800 fits in their frequency difference.

Web server

We have already noted that Apache Benchmark leads Intel quad-core processors into some strange stupor. Here is another proof: four cores at 3 GHz are outperformed (even if nominally) by two cores at 2.93 GHz. How could it happen? We've come up with only one hypothesis so far: a lot of threads jump from core to core with a non-shared L2 cache and pollute it so much that caching becomes inefficient.


The rendering module of CPU RightMark can use up to 32 processors. So there is nothing surprising about the results of the "4 vs 2 cores" competition - quad-core processors take top lines in the diagram.


The archivers somehow use the two additional cores, or the difference between X6800 and QX6850 wouldn't have been so noticeable. But the authors still have some issues to improve.


QX6850 outperforms its closest competitor solely due to its higher clock rate, twice as many cores give absolutely no advantage here. However, we already wrote that FineReader did not enable SMP optimization in the batch recognition mode.

Audio Encoding

It's the old group of tests, which have lost their relevance because of high predictability of their results. No comments.

Video Encoding

Most video codecs used in our tests support two or four cores, so the advantage of quad-core processors in this test does not come as a surprise.


A purely nominal advantage of QX6850 over X6800 suggests two ideas: firstly, four cores will give no real advantages in games, that's for certain (many game developers still don't know what to do with two cores...); secondly, performance seems to be limited by a graphics card here.

Total score

Funny, the total score actually puts on a par four cores at 2.66 GHz and two cores at 2.93 GHz (Core 2 eXtreme QX6700 and X6800). It's a demonstration for enthusiasts, who are raving about the forthcoming advent of quad-core processors to the mass market: It was enough to increase the clock rate of two cores by 0.27 GHz instead of using four cores. :) QX6850 breaks away from a couple of its closest competitors by 12% owing to three advantages: firstly, it's a quad-core processor (unlike X6800); secondly, it has the highest core clock; and thirdly, it has the fastest bus. Unfortunately, we cannot determine a contribution of each advantage to the final result, because we don't have other Intel Core processors with the same bus clock, or the same core clock.

Estimated power consumption

The difference in idle power consumption between QX6700 and QX6850 can hardly be explained solely by higher frequencies of the bus and cores - it's too big. We can only assume that BIOS of our motherboard is not finetuned enough, and some power saving features are disabled (for example, we failed to register a core clock reduction, although the testbed was idle for more than two hours.) It makes no sense to blame the motherboard manufacturer either - this CPU did not officially exist when we ran our tests. What concerns power consumption under 100% load, there are no surprises here. 3 GHz for this core manufactured by a given process technology is close to the limit, so it would have been naive to expect power saving miracles. To crown it all, it's a quad-core processor...


We can actually only repeat the title of this article: store is no sore. Intel hardly designed Core 2 eXtreme QX6850 to prove anything. It's crystal clear that the company is beyond competition in the top segment of x86 processors until AMD launches a cardinally new Athlon core. That's why we are not in raptures over the QX6850, despite its super-high performance results. Another top solution. Fast. Relatively hot (no wonder - the clock rate is higher, while the process technology has not been changed). The bar has been raised by another several centimeters. We are waiting for the competitor to jump...

Memory modules for our testbeds are kindly provided by
Corsair Memory Russia

Stanislav Garmatiuk (nawhi@ixbt.com)
July 16, 2007

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