Core 2 Duo vs Core 2 Quad


Product(s): Intel Core 2 Duo X6800, Intel Core 2 Quad Q6700

Provided By: MemoryExpress
Price: $1299.95, $1299.95




These are interesting times in the computer industry.  Intel’s Core 2 Duo is barely dry behind the ears and they have dropped the bomb with their Quad Core CPU – the Core 2 Quad Q6xxx series.  At this point, AMD has nothing that can touch the Core 2 Duo in terms of performance, and Intel is not resting on that fact – they are pushing things even farther.  The only Quad Core processor that is currently available is the Core 2 Extreme QX6700 and it comes clocked in at 2.66GHz with 4x 2MB of cache.  Be prepared for this CPU to cost as much as a nice house payment however – it is currently listing for $1299.95 CDN, if you can find one in stock.

Processor Lineup - Top
Processor Lineup - Top


The Core 2 Duo processor has proved itself to be a powerhouse, and to get the best of the best will set you back a fair bit of change as well.  Currently, the fastest Core 2 Extreme X6800, and this processor comes clocked in at 2.93GHz with 2x2MB of cache.  This processor will also set you back $1299.95 CDN right now and offers half the cores, but at greater speed than the new Quad Core 2 Extreme CPU.


Our goal today is to take a look at these CPU’s when compared to each other running popular applications, a few CPU intensive games, and some synthetic benchmarks.  Our goal is to provide you with some information that will help you decide if the world is even ready for Quad Core Personal Computing.


Initial Thoughts:


Both of these processors brandish the “Extreme” tag, and are extreme not only in price, but in performance and potential.  The Extreme processor usually runs with less CPU core voltage than regular E6x00 series processors.  This indicates that these processors are the cream of the crop and will likely clock higher than other CPU’s.  This is not a hard and fast rule, but merely an indicator of what you can expect.

Processor Lineup - Bottom
Processor Lineup - Bottom


When it comes to choosing a high-end processor, you must really think about what you are going to be doing with it.  In terms of gaming performance, a Dual Core CPU will probably give you better performance and value today as dual core CPU’s are clocked higher and games can only handle one or two threads at once.  Quad core CPU’s should excel in video editing, design, and pure mathematical calculations as more applications are multithreaded for 2 or more cores.  With that in mind, we’ll take a look at how the processors compare in terms of basic specs.


Intel QX6700 & X6800 Quick Specs.
Internal Clock
External Clock
L2 Memory

Core 2 Extreme QX6700
1066FSB (266x4)
4 MB x 2

Core 2 Extreme X6800
1066FSB (266x4)
2 MB x 2

On the next page we'll take a look at how these processors overclock and take a look at our test system.


Both of these processors had quite a bit of headroom when it came to overclocking.  The X6800 comes clocked in at 2.93GHz with an 11x Multiplier.  With modest core voltage increases we actually managed to post at 4GHz but we couldn't boot into Windows at this speed.  We had fair success at 3.8GHz, but settled at 3.641GHz at 1.37v.  At this speed the system was rock solid for a week of 100% CPU load with a Zalman CNPS8000 cooler.

Reference X6800 O/C
Reference X6800 O/C

I didn't know what to expect with the QX6700 processor.  This little beauty comes clocked in at 2.66GHz with a 10x Multiplier.  Our original goal was to make 3.0GHz with the smaller Zalman CNPS8000 cooler, but we reached that at stock voltages and pushed higher.  We ran this processor at 1.37 as well, and managed to reach 3.2GHz rock solid.  We hit 3.25GHz and completed quite a few tests at this speed, but then started to experience system instability.  Once we dropped it down to 3.2GHz, we remained stable for a solid week at 100% CPU load.  At 3.25GHz with a quad core processor, we had 13GHz of screaming Core technology under a single HSF.  When we ran full load tests, we topped out the temperature around 60C with high fan speed.  I believe this is partly why we experience instability.  Better cooling would have confirmed this.  Unfortunately, a better cooler didn't arrive in time.

Reference QX6700 O/C
Reference QX6700 O/C

Test System:

Our test system consisted of the following components:

  • MSI 975X Platinum v.2 "PowerUp Edition" Motherboard
  • Intel Core 2 Duo X6800 CPU - Memory Express
  • Intel Core 2 Quad QX6700 CPU - Memory Express
  • 2GB Kit Crucial PC2-8000 - Crucial
  • eVGA 7950GX2 1GB Graphics Card - Memory Express
  • Seagate 7200.10 SATA II HDD
  • Plextor PX-750A DVDRW
  • Windows XP Professional SP2

On the next page we'll jump into some synthetic benchmarks.

Theoretical Quad Core & Dual Core Performance:

We start things off with synthetic benchmarks as they give us an idea of what to expect in a world that is optimized for dual core and multi core processors.  You can clearly see in some of the test results below that pure MHz clock is what wins.  There are other tests that are optimized for multi-core processors and take advantage of all four cores of the QX6700 exhibit different results.

3DMark Series

PCMark 2005






SiSoft Arithmetic

SiSoft Multimedia

SiSoft Memory Bandwidth

Quite a few of the above benchmarks show a decent advantage of a quad core setup, but how will that translate in real world apps?  Take a look on the next page.

Multi-Core In The Real World:

The following applications were not necessarily hand-picked because they show multi-core performance increases.  We did try to round up some applications that took advantage of multiple cores, but please realize that dual-core and multi-threaded applications are still becoming popular.  In the future we will likely see greater gains from more than two cores, but for now, well, it's the real world.

Adobe Premier & Photoshop

Audio Conversion

ConvertX to DVD

DivX & Quicktime

DVD Shrink

WinRAR File Compression

On the last page we'll take a look at gaming performance and then cover a few other ideas before we wrap things up.

Multi-Core Gaming:

There are a few games that take advantage of multi-core gaming, but from our experience they don't really show improvement beyond two cores.  The two games we included below have shown the greatest response to CPU speed boosts on our test system, so we included these games below.



It's not surprising that games show a greater performance increase due to increased clock speed than increased cores.  At medium resolution and detail settings the games all show a performance increase in their minimum framerates when clocking up the system, but the difference between core count is not even a factor.  At this point, multi-core gaming still hasn't caught on.  Valve promises to change this in Half-Life 2: Episode 2, but until then we are left pretty flat with the latest games.


General Experience:

Intel claims that the Core 2 Duo is "The World's Greatest Dual Core Processor", and I believe that they are right.  What can be better than "the world's best" dual core?  Quad core my friend - quad core.  The idea behind a good dual-core processor is that when the machine is doing one intensive task, it still has a processor left to handle other tasks.  For most people dual core is ample, but for some extreme users today, quad core may offer some benefits.  We loaded up our rig with a bunch of applications and ran WinRAR, Quicktime, Adobe Premier and scanned for Virus at the same time and both systems performed quite well.  With so many intensive applications running, the QX6700 setup ran smoother however and felt less laggy when trying to open applications like Office 2007 or Firefox.

In reality, most people will not be running multiple instances of video encoding simultaneously at the same time they are compressing files and doing other tasks.  The Quad Core QX6700 makes this possible, but it's overkill for many users.


Unless you are going for pure bragging rights a quad core processor really is ahead of it's time.  While there are a few real world applications that take advantage of this processors multi-threaded power, most do not.  In theoretical tests, the quad core runs away with the competition, but in reality it's a give and take.  Now that the QX6700 is upon us, more software development companies will start taking advantage of multiple cores and then the processors will excel.  If you are planning on spending $1300 on a processor that you will trade off in 6 months, I'd have to recommend the X6800 over the QX6700 at this time.  Overall performance with the X6800 is marginally better than the QX6700, but I'm sure that will change in time.

On a side note, my only fear of multi-core computing is that programmers will get sloppy and won't take the time to optimize code for efficiency.  Instead they will just load balance across cores and let the massive CPU power do the work.

I'd like to thank MemoryExpress for the opportunity to play with these processors, and at the same time express my disappointment that I have to return them.  After using a test setup equipped with these processors my Athlon 64 3800+ X2 feels mighty slow.

If you have any questions, comments or general feedback, please post it in the forum at the "Comments" link below.