by Ilya Gavrichenkov
08/31/2007 | 12:01 PM
The Intel processor price cut that occurred a month ago turned into an important milestone on the multi-core processors’ way to user computer systems. The price of quad-core processors has finally dropped down to the level of dual-core solutions. To be more exact, the youngest model in the official Core 2 Quad lineup is priced exactly the same as the top Core 2 Duo CPU. This price, by the way, is set at $266, which seems quite sufficient to make processors with four computational cores much more popular than they used to be before.
<%BANNER[article]%>This particular situation inspired us to undertake another analytical investigation where we decided to arrange a duel between dual-core and quad-core processors priced identically. I am talking about Core 2 Duo E6850 and Core 2 Quad Q6600. True, a lot of users found themselves facing this difficult choice, as the above mentioned processor models are currently sold in retail stores at comparable prices. However, these processors are so different in their specifications that even true professionals cannot always make the most optimal choice between them with all certainty. These processors feature not only different number of computational cores, they also work at very different clock speeds and support busses running with different frequencies.
There is an opinion that a lot of resource-hungry applications that have be released or updated recently, can take real advantage of multi-core processor capabilities. At the same time, this is not always true about the older applications and games, the majority of which are still working with only one of two computational threads. Therefore, we decided to perform a special test session that will make a lot of things clear and help us decide if quad-core processors can really replace high-speed dual-core CPUs in different applications.
It is also very interesting to see the outcome of Core 2 Duo E6850 and Core 2 Quad Q6600 rivalry because both these processors use absolutely identical semiconductor dies. The thing is that contemporary quad-core Intel processors consist of a pair of dual-core dies mounted within the same LGA775 package. That is why we can actually expect dual- and quad-core processors from the Core family to demonstrate similar overclockability. This, at the same time, dives us some hope for Core 2 Quad Q6600 to overclock to the top frequencies that can be achieved with Core 2 Duo E6850. In other words, it should be even more exciting to compare Core 2 Duo E6850 and Core 2 Quad Q6600 from the overclocking standpoint than in the nominal operational mode. Moreover, both, Core 2 Duo E6850 as well as the recently released Core 2 Quad Q6600 are based on the new G0 core stepping, that boasts slightly better overclocking potential, according to our previously conducted research.
We can get a practical idea of the highs and lows of every solution by comparing their formal specifications. Let’s compare side by side the official specs of Core 2 Duo E6850 and Core 2 Quad Q6600 (new G0 core stepping):
Core 2 Duo E6850 | Core 2 Quad Q6600 | |
Code name | Conroe | Kentsfiled |
Nominal frequency | 3.0 GHz | 2.4 GHz |
Bus frequency | 1333 MHz | 1067 MHz |
Multiplier | 9x | 9x |
L2 cache | 4 MB | 2 x 4 MB |
Number of cores | 2 | 4 |
Packaging | LGA775 | LGA775 |
Manufacturing process | 65 nm | 65 nm |
TDP | 65 W | 95 W* |
Vcore | 0.962-1.350 V | 1.100-1.372 V |
Enhanced Halt State (C1E) Technology | Yes | Yes |
Enhanced Intel Speedstep | Yes | Yes |
Execute Disable Bit | Yes | Yes |
Intel EM64T | Yes | Yes |
Intel Thermal Monitor 2 | Yes | Yes |
Intel Virtualization Technology | Yes | Yes |
The advantages of dual-core Core 2 Duo E6850 over the quad-core Core 2 Quad Q6600 look as follows:
The advantages of the quad-core Core 2 Quad Q6600 over dual-core Core 2 Duo E6850:
Well, each of the CPUs has its highs and lows. Nevertheless, the major drawback of Core 2 Quad Q6600 is its lower clock frequency of 2.4GHz. However, this issue can be resolved by overclocking, can’t it? So, let’s take a closer look at the processors that are sitting in out lab and find out if the overclocked quad-core Core 2 Quad Q6600 will be able to run at the same frequencies as the dual-core Core 2 Duo E6850.
For our overclocking and performance experiments we assembled a special test platform that included not only above mentioned CPUs but also other hardware components specifically aimed at efficient overclocking.
Our overclocking platform was built on the new Asus Blitz Extreme mainboard targeted for gaming enthusiasts. This is the only DDR3 SDRAM on Intel P35 Express based mainboard in the market today that supports “PCI Express 8x + PCI Express 8x” CrossFire configurations thanks to the additional Crosslinx chip.
However, the primary reason why we picked this particular mainboard was its overclocking potential. It allows changing the FSB frequency from 200MHz to 800MHz, gives access to all Intel P35 FSB:DRAM multipliers and offers extensive options for voltage adjustment. For example, the processor core voltage can be increased to 1.9V, the chipset North Bridge voltage – to 2.03V, the DDR3 voltage – to 3.04V. Moreover, the board offers options for FSB Termination Voltage and PLL Voltage adjustment, which may be very helpful during CPU overclocking by raising the FSB frequency significantly. Also, Asus Blitz Extreme boasts very flexible memory controller configuring options, which are as good as those of Asus P5K Deluxe.
Asus engineers paid special attention to processor voltage regulator circuitry. The mainboard is equipped with an eight-channel CPU voltage regulator assembled with high-frequency MOSFET. Moreover, it also boasts a Loadline Calibration function that helps eliminate pretty unpleasant Vdroop-effect – processor Vcore drop under increasing workload. Also, Asus Blitz Extreme features one more unique distinguishing feature: dual-channel memory voltage regulator circuitry that should have a positive effect on DDR3 SDRAM overclocking.
I have to stress that Asus Blitz Extreme has the whole bunch of other interesting features, such as SupremeFX II external HD audio-module, additional diagnostic LCD screen, numerous status LEDs on the PCB, opportunity to use liquid-cooling within the chipset cooling system, and many others. However, we are not going to dwell on any of these features today, because they have minimal effect on the mainboard’s overclocking potential.
The memory subsystem of our overclocking platform was built with the new DDR3 SDRAM memory kit from OCZ Technologies that support up to 1800MHz frequencies.
OCZ DDR3 PC3-14400 Platinum Edition kit includes two memory modules 1GB each that are designed to work at 1800MHz with 8-8-8-24 timings and 1.95V voltage. Of course, these modules are built with the new gigabit DDR3 chips from Micron.
I have to point out that OCZ DDR3 PC3-14400 Platinum Edition kit reveals its potential at 450MHz FSB with the smallest Intel P35 FSB:DRAM divider of 1:2. This fact allowed us to deal with processor overclocking without worrying about the memory subsystem parameters settings.
To cool the CPUs we chose Scythe Infinity cooler that proved very efficient over time.
With a pair of high-speed (about 1900rpm) 120-mm fans installed for additional air intake and oust this cooler is truly one of the most efficient cooling solutions these days.
So, summing up everything we have just said, here is the detailed list of hardware components we used for our test platform:
We have had Core 2 Duo E6850 processor in our lab for quite some time now. Preparing for the launch of platforms with 1333MHz bus Intel sent us this sample. Like all other CPUs supporting 1333MHz bus, this processor is based on G0 core stepping that boasts lower heat dissipation and slightly better frequency potential.
This CPU runs at 3GHz default frequency achieved as 9 x 333MHz, i.e. Core 2 Duo E6850 has the highest working frequency of processors on Core micro-architecture today. The nominal VID of this particular piece is 1.35V.
We have already overclocked this processor before. In the first review of this solution called New Member In Core 2 Duo Processor Family: Introducing CPUs with 1333MHz Bus we managed to overclock it to 3.79GHz with the Vcore raised to 1.5V. Although that time we used a different cooler: Zalman CNPS9700 LED. This time we are going to use a more efficient Scythe Infinity cooler. So we could easily push the voltage to 1.55V and hit even higher 3.85GHz speed.
In this case the CPU not only passed all the standard tests, but also successfully passed the 12-hour Small FFT stress-test in Prime95 25.3 supporting multi-core processors.
FSB frequency in this case reached 428MHz. As a result, the memory was clocked at 1712MHz frequency with 8-8-8-24 timings. We ensured its stability by pushing the memory voltage to 1.9V.
The second processor participating in our tests today, Core 2 Quad Q6600, arrived in our lab just not so long ago. Although these processors have been selling in stores for over one and a half years already, they became especially interesting quite recently. The thing is that on July 22 Intel not only cut all the processor prices down in half, but they also transferred these particular processor models to a more progressive G0 core stepping.
According to the official data, quad-core processors based on new core stepping boast lower heat dissipation and can work at higher temperatures than their predecessors. Thus, the heat dissipation of the new Core 2 Quad Q6600 modification on G0 stepping dropped from 105W to 95W.
We ere impatiently waiting for the Core 2 Quad Q6600 on the new core stepping to arrive in our lab. There were many reasons to believe that it would be better overclockable than its predecessors and it seems like a perfect opponent to the dual-core Core 2 Duo on G0 stepping.
Luckily, we have finally got our hands on a processor like that.
As you can see from the screenshot, Core 2 Quad Q6600 works at the nominal 2.4GHz frequency achieved as 9 x 266MHz. The total capacity of its L2 cache is 8MB, however it is split in two parts, each shared between a pair of cores within each die of the quad-core processor. The processors nominal VID was set at 1.2625V.
Note that the CPU participating in our tests is a serial unit. Its S-Spec is SLACR. This particular marking helps to distinguish this processor visually from the predecessor on B3 core stepping with SL9UM S-Spec. As you know, S-Spec is marked on the boxes of boxed CPUs and on the processor heat-spreader.
So, looks like Core 2 Quad Q6600 should overclock at least as well as Core 2 Duo E6850 as it is based on absolutely identical semiconductor dies, although twice as many. However, it is exactly the double number of dies within the same package that makes it harder to overclock quad-core processors on Core micro-architecture. Even such high-performance air-coolers as Scythe Infinity with two fans have hard time coping with Core 2 Quad cooling during extreme overclocking. By the way, this is exactly the reason why it is so important to pick the right cooling solution for Core 2 Quad processors, so don’t underestimate this task.
We managed to overclock Core 2 Quad Q6600 to 3.6GHz by raising the FSB frequency to 400MHz and pushing the voltage to 1.4V.
In this case the CPU passed successfully the 12-hour stress-test in Prime95 and completed a standard set of benchmarks.
Note that the temperature of some processor cores in this case hit pretty high values.
The memory worked just fine at 1600MHz with 7-7-7-20 timings and its voltage was increased to 1.9V.
Further overclocking of our Core 2 Quad Q6600 processor was possible theoretically, but required additional Vcore increase. Unfortunately, in our test platform with air-cooling it resulted in uncontrolled increase in processor temperature and throttling kicked in.
Within our performance test session we will compare the dual-core Core 2 Duo E6850 running at the default 3.0GHz frequency and overclocked to 3.85GHz against the quad-core Core 2 Quad Q6600 working at the nominal 2.4GHz and overclocked to 3.6GHz.
PCMark05 benchmark is pretty old, its multi-core processor support is quite superficial. Nevertheless, a lot of users out there use this particular benchmark to evaluate the systems performance, that is why we simply couldn’t give it up.
The total PCMark05 score indicates that Core 2 Duo E6850 outperforms Core 2 Quad Q6600 in nominal mode. However, since we managed to overclock the quad-core processor by 50%, while its dual-core brother hit only 28.5% higher frequency, the picture changes to completely the opposite during overclocking.
CPU Benchmarking suite is slightly better optimized for quad-core processors, it even has a test where the CPU is loaded with four resource-hungry tasks at the same time. As a result, the situation is a little different from what we just saw on the previous diagram: Core 2 Quad Q6600 defeats the competitor in this case even in the nominal mode. And after overclocking, its advantage becomes even more convincing: it appears over 23% faster than Core 2 Duo E6850.
However, during the memory subsystem tests quad-core processor performs a little worse. Core 2 Duo E6850 and Core 2 Quad Q6600 have identical multiplier of 9x. However, the quad-core processor runs at lower FSB frequencies. This appears the major factor limiting the data transfer rate between the Core 2 Quad CPU and the system memory.
It was perfect timing for us to receive the new version of SYSmark 2007 testing suite that measures the system performance in real applications. Thanks to this testing software we can get an even better idea of the tested platforms’ abilities in real life.
Core 2 Duo E6850 gets better total score in nominal mode, while Core 2 Quad Q6600 wins during overclocking. However, it is actually much more interesting to check out not the average results, but the scores obtained in individual applications.
This testing scenario creates a tutorial web-site with diverse media content. It involves the following applications: Adobe Illustrator CS2, Adobe Photoshop CS2, Macromedia Flash 8 and Microsoft PowerPoint 2003.
Of course, the above listed applications are not quite optimized for multi-threading that is why in both, nominal and overclocked modes, Core 2 Duo E6850 wins the race.
This test deals with creating videos using non-linear editing and special effects. The videos are put together from several sources, including static images. The final video is made in two formats: HD and for online internet viewing. In this case the following applications are involved: Adobe After Effects 7, Adobe Illustrator CS2, Adobe Photoshop CS2, Microsoft Windows Media Encoder 9 and Sony Vegas 7.
As is know, software developers were among the first ones to optimize their media content processing tools for multi-core processors. That is why you will hardly be surprised to see that Core 2 Quad Q6600 did best of all here.
The next scenario emulates typical office work including e-mail, data processing, project management and document editing. These are the applications involved: Microsoft Excel 2003, Microsoft Outlook 2003, Microsoft PowerPoint 2003, Microsoft Word 2003, Microsoft Project 2003 and WinZip 10.0.
In nominal mode the winner’s laurels go to the dual-core processor with higher clock frequency. Overclocking, however, balances out both rivals.
The last test deals with creating an architectural presentation with a photorealistic image of the object and a fly-around video of the projected building. There are only two applications used: AutoDesk 3ds Max 8 and SketchUp 5.
The results are quite logical. The dual-core Core 2 Duo E6850 with 25% higher nominal frequency wins in the nominal mode, while the quad-core Core 2 Quad Q6600 takes the lead after overclocking.
Gamers have always been pretty careful about quad-core processors. Most contemporary games can create one or two simultaneous computational threads at the most that is why the majority of users believe that higher working frequency is more efficient for gaming than multiple processor cores, so high-speed dual-core processor should be a better choice.
Nevertheless, stereotypes do not always reflect the ever changing situation correctly. Games still take their time in learning to use the advantages of multi-core technology. However, there are other factors that may affect the situation in the end of the day. Firstly, graphics card drives received fully fledged support of multi-core processors. Secondly, Windows Vista operating system manages to distribute computational threads among the cores quite intelligently (especially compared with Windows XP), which gives the games that don’t have four parallel threads the opportunity to benefit from larger L2 cache of the quad-core processors. And the gaming tests we performed this time illustrate this statement very clearly.
For our session we used five pretty contemporary games. The tests were run in 1024x768 resolution, without FSAA. The image quality settings were left at defaults.
Quake 4 supports only dual-core processors. True, Core 2 Duo E6850 with higher clock frequency defeats the competing quad-core solution. However, overclocking changes the situation dramatically. Although overclocked Core 2 Duo E6850 works at a little higher frequency than the overclocked Core 2 Quad Q6600, it is the quad-core CPU that wins here. The determinative factor in this case is the two L2 caches with the total capacity of 8MB.
F.E.A.R. is actually a single-thread game. Nevertheless, the overclocked to 3.6GHz Core 2 Quad Q6600 is considerably faster than the dual-core Core 2 Duo E6850 working at 3.85GHz. This time the graphics driver optimizations played a crucial role.
Another single-threaded game, Company of Heroes, finally lets the dual-core processor to take the lead in nominal and overclocked work modes.
However, the picture changes to just the opposite in Supreme Commander. No wonder, since this game is practically the only one in the market today that supports quad-core processors. That is why Core 2 Quad Q6600 leads the race even without any overclocking.
And finally, we see pretty common picture in Lost Planet: Extreme Condition. The game itself by default creates two computational threads, however larger L2 cache of the quad-core processor grants its victory in overclocked mode. In nominal work mode Core 2 Duo E6850 wins the first prize as it boasts considerably higher working frequency.
UPDATE: However, you can make Lost Planet: Extreme Condition game work on quad-core processors, too, where there are four threads created. There is an option called “Concurrent Operations” in the Options menu. By changing it from 2 to 4 you can obtain even more impressive results on Core 2 Quad Q6600.
Summing up the results we have just seen, I can conclude that if the gamers don’t feel like overclocking their processor, they shouldn’t go for CPUs with more than two cores. Gamers-overclockers should definitely decide in favor of the Core 2 Quad Q6600, although a strong opposite opinion exists these days.
All contemporary video codecs have high-quality optimization for multi-core processors. That is why Core 2 Quad Q6600 defeats Core 2 Duo E6850 even without overclocking.
Apple iTunes, unfortunately, can only create two threads. That is why the Core 2 Duo E6850 with higher clock frequency wins in this test in both: nominal and overclocked modes.
3D rendering is one of the best-paralleled tasks. Therefore the number of computational cores is crucial for applications like that.
Core 2 Quad Q6600 performs very well in Excel 2007. Its advantage over the dual-core Core 2 Duo E6850 hits 63% in nominal mode and 78% after successful overclocking.
WinRAR archiving tool also can benefit from additional computational cores. Out of two processors priced similarly, it is the quad-core Core 2 Quad Q6600 that performs best here.
As for Photoshop CS3 and Microsoft Movie Maker 6.0, the situation is not so simple. Core 2 Duo E6850 wins in nominal mode, while quad-core processor again takes the lead after successful overclocking.
By dropping the price of the youngest quad-core processor below $300, Intel made a great gift for hardware enthusiasts. Our today’s test session revealed that this processor can really do great in skillful hands. The overclocking potential of the Core 2 Quad Q6600 processor based on the new G0 core stepping is quite sufficient to help it compete successfully in almost any applications.
According to our tests and numerous overclockers’ reports online, quad-core Core 2 Quad Q6600 processors can overclock up to 3.6GHz with proper air-cooling. In this case they can perform better than Core 2 Duo CPUs overclocked to their maximum. Moreover, we see this tendency even in those applications that are not optimized for multi-core processors and that are getting fewer day by day. As we saw there are very few tasks left, where overclocked quad-core processors cannot outperform overclocked dual-core CPUs. They defeat their rivals not only thanks to twice as many computational cores, but also thanks to twice as large L2 cache.
So, we think Core 2 Quad Q6600 seems to be a much more attractive offering these days than Core 2 Duo E6850.
However, those computer users who do not want to mess with processor overclocking may think differently. In this case Core 2 Duo E6850 with 25% higher clock speed performs better in a lot of applications, including games. Moreover, it is also more economical. As a result, the most optimal choice for a system working at nominal speeds would depends a lot on the type of tasks it is intended for.
Nevertheless, we shouldn’t forget that most upcoming applications and games are being designed with multi-threading in mind. That is why Core 2 Quad Q6600 may be a more promising solution even if used in its nominal mode.