Intel Core 2 Duo - Printer Friendly version

1. Introduction

In April of 2005, Intel announced the Intel Pentium processor Extreme Edition, featuring an Intel dual-core processor, which boosted multitasking computing power and improved the throughput of multithreaded applications.

An Intel dual-core processor consists of two complete execution cores in one physical processor, both running at the same frequency. Both cores share the same packaging and the same interface with the chipset/memory. Imagine that a dual-core processor is like a four-lane highway - it can handle up to twice as many cars as its two-lane predecessor without making each car drive twice as fast. Similarly, with an Intel dual-core processor-based PC, people can perform multiple tasks such as downloading music and gaming simultaneously. Overall it offers a way of delivering more capabilities while balancing energy-efficient performance, and is the first step in the multi-core processor future.

- Core 2 Duo

Core 2 is a ninth-generation x86 architecture microprocessor produced by Intel and it was officially released on July 27, 2006. The Core 2 brand is subdivided into Duo (dual-core) and Extreme (high-end) models, with a possible Solo (single-core), and a confirmed -upcoming- Quad (quad-core), in early 2007.

Unlike NetBurst-based processors (Pentium 4/D), Core 2 does not stress designs based on extremely high clock speeds but rather improvements on other CPU features, including cache efficiency and number of cores. The power consumption is only 65 W, making Core 2 the lowest power consumption desktop chip currently on sale.

Intel Core 2 processors feature x86-64, Virtualization Technology, Execute Disable Bit, and SSSE3. The release also introduced LaGrande Technology, Enhanced SpeedStep Technology, and Active Management Technology (iAMT2).

Feature	Benefit
Latest 3rd generation Intel dual-core processing	Unrivaled performance. Two independent processor cores in one physical package, up to 4 MB of shared L2 cache and up to a 1066 MHz Front Side Bus for desktop PCs and up to 667 MHz Front Side Bus for laptop PCs.
Intel Intelligent Power Capability	Excellent energy optimization delivering more energy-efficient performance. A set of capabilities designed to reduce power consumption. Manages the runtime power consumption of all the processor's execution cores.
Intel Wide Dynamic Execution	Do more at once. Improving execution speed and efficiency while delivering more instructions per clock cycle. Each core can complete up to four full instructions simultaneously.
Intel Smart Memory Access	A PC that won't slow you down. Newly designed, optimized functions for reducing wait time, keep the pipeline full improving instruction throughput and performance.
Intel Advanced Smart Cache	Access the programs and files you need faster. The shared L2 cache is allocated to each processor core based on workload up to the full amount of total cache. This is more efficient than today's dual-core processor. Sharing the cache significantly reduces the time needed to retrieve frequently used data improving performance.
Intel Advanced Digital Media Boost	Entertainment that rocks. 128-bit Streaming SIMD Extensions (SSE) instructions are issued one per clock cycle doubling their speed of execution over previous generation processors. This benefits a broad range of applications including video, audio, and more with improved performance.
Intel 64	Serious access to system resources. Enables the processor to access larger amounts of virtual and physical memory.
Execute Disable Bit²	Hackers, viruses, and malware-rejected. Provides enhanced virus protection when deployed with a supported operating system preventing certain viruses from infecting the system.

- Future

Besides the currently offered Core2Duo series, Intel has plans for the near future, that are very interesting, to say the least. Intel will deliver a quad-core (4 full execution cores) processor to the DP server segment, based on Intel Core micro-architecture, code-named "Clovertown." Clovertown is targeted for introduction in the fourth quarter of 2006, for the Bensley and Glidewell platforms. For the MP server segment, Intel is also developing an MP server processor optimized for quad core, based on Intel Core micro-architecture, code-named "Tigerton." The Tigerton processor is targeted for introduction in 2007 and will work within the Caneland server platform.

Intel will also deliver a quad-core (4 full execution cores) processor for high-end desktops, based on this new micro-architecture, code-named "Kentsfield." Kentsfield is targeted for introduction in the first quarter of 2007.

2. Core 2 Duo Line

- Conroe

The first Intel Core 2 Duo processor cores, code-named Conroe, are built on a 65 nm process and are intended for replacing Pentium 4 and Pentium D series. Intel claims that the Conroe series provides 40% more performance at 40% less power, compared to the Pentium D. The Conroe processors are labeled as the E6600 and E6700 Core 2 Duo models, with the E6600 clocked at 2.4 GHz and the E6700 clocked at 2.67 GHz. The family has a 1066 MT/s front side bus, 4 MB shared L2 cache, and 65 watts TDP. The E6600 and E6700 have 4MB L2 cache, while the E6300 and E6400 versions have 2MB L2 cache.

- Conroe XE

This is currently, the top-of-the-line for Intel's CPU product line. It replaces the Pentium 4 Extreme Edition and the dual-core Pentium Extreme Edition processors. Core 2 Extreme has a clock speed of 2.93 GHz and a 1066 MT/s FSB. The TDP for this family is 75-80 watts. According to Intel, at full load the XE6800 does not exceed 45 °C (113 °F), and with SpeedStep enabled, the average temperature of the CPU when idle is 25 °C.

Like the desktop Core 2 Duo, it has 4 MB of shared L2 cache available. This means that the only major difference between the regular Core 2 Duo and Core 2 Extreme is the clock speed. The good thing is that it comes with an unlocked multiplier, allowing good overclocking abilities and of course, underclocking to reduce overall temperature.

- Allendale

Allendale is a codename for the stripped down versions of the Conroe processors with only 2 MB of L2 cache. The E6300 (1.86 GHz) and E6400 (2.13 GHz), both have a 1066MT/s FSB.

Below you will find a table with all the Core2Duo CPU line and its main specs:

	Intel Core2 Duo Processor XE6800	Intel Core2 Duo Processor E6700	Intel Core2 Duo Processor E6600	Intel Core2 Duo Processor E6400	Intel Core2 Duo Processor E6300
Processor Number	XE6800	E6700	E6600	E6400	E6300
Architecture	65 nanometer technology
L2 Cache	4M	4M	4M	2M	2M
L3 Cache	N/A
Multiplier	11x	10x	9x	8x	7x
Clock Speed	2.93 GHz	2.66 GHz	2.40 GHz	2.13 GHz	1.86 GHz
Front Side Bus Speed	1066 MHz
Other Intel Technologies	Intel EM64, VTΒ, Execute Disable BitΒ, dual-core, EIST
Thermal Design	75W	65W
Package	FC-LGA
Chipset	Intel 975X Intel P965	Intel 975X Intel P965 Intel 946PL Intel 946GZ Intel Q965 Intel Q963 Intel G965
Slot/Socket Type	LGA775
Pin Count	775-land
sSpec Number	SL9S5	SL9S7	SL9S8	SL9S9	SL9SA

- Compatibility

As the above table shows, all Core2Duo series are the Socket LGA775. However, not every motherboard is compatible. Supporting chipsets besides Intel's (975X, P/G/Q965, Q963, 946GZ/PL) are:

ATI's Radeon Xpress 200, RD600 and RS600
NVidia's nForce 4 SLI Intel Edition and nForce 570/590 Intel Edition
VIA's PT880/PT880 Ultra, PT890, PM880 and PM890.

Keep in mind that older motherboards may not support the Conroe due to the fact that it requires a newer voltage regulator module (VRM), the VRM 11.

3. Installation

There isn't a lot to say here, just take care when installing the CPU! After connecting all necessary power cables, you can power up your system.

XE6800 Info:

X6600 Info

4. Test setup

For comparison, we had in our labs, two Core2Duo CPUs (XE6800, E6600) and a previous generation (D930). Both the XE6800 and D930 are clocked at the same speed ~ 3.0GHz, but have different memory cache and architecture. All tests were carried out with the following setup, with memory timings at 5-5-5-15-30 to allow 1067MHz FSB:

Motherboard: Asus P5B Deluxe Wi-Fi Edition BIOS 706b/711 revisions
Memory: 2x1GB Crucial PC-8000
VGA: MSI 7600GT Silent with Nvidia 91.47 installed
HDD: WD 80GB SATAI (primary)
HDD: Seagate 80GB SATAII (secondary)
Operating system: Windows XP SP2 with all latest updates installed

We used a variety of software, from benchmark to games:

Sisoft Sandra 2007 SP1
Everest Lavasys Ultimate Edition 2006 v3.00.717 beta
SuperPI Mod v1.5XS
PC Mark05 v1.1.0
3D Mark06 v1.2.0
Recode v2.3.1.8
Science Mark 06
POV 3.70 beta15
Cinebench v9.5
Prey v1.0
Splinter Cell v1.05
F.E.A.R v1.06
HL2 Episode 1 June 2006 Edition

5. Everest Ultimate Edition 2006

EVEREST Ultimate Edition is an industry leading system diagnostics and benchmarking solution for enthusiast PC users, based on the award-winning EVEREST Technology. During system optimizations and tweaking, it provides essential system and overclocking information, advanced hardware monitoring and diagnostics capabilities to check the effects of the applied settings. CPU, FPU and memory benchmarks are available to measure the actual system performance and compare it to previous states or other systems. Furthermore, complete software, operating system and security information makes EVEREST Ultimate Edition a comprehensive system diagnostics tool that offers a total of 100 pages of information about your PC.

The software has built-in, several tests for both memory and CPU/FPU. Note, that memory results are expected to be lower for the D930 due, to the lower FSB (800MHz vs 1067GHz). As was expected, the XE6800 is the fastest processor, by a small margin:

In the FPU/CPU tests, we have greater differences:

The XE6800 is around 16.14% faster than the E6600 and almost 71.62% than the D930. Let's move on to the Sisoft Sandra 2007 SP1 results.

With Sisoft Sandra 2007 SP1, the XE6800 again shows that it is the leading performer, being 21.22% faster than the E6600 and 187.93% than the D930 (sum up of all sisoft sandra scores).

6. PCMark

PCMark®05 is everything you need to reliably and easily measure the performance of your PC and determine its strengths and weaknesses. With PCMark05, you will be able to select the optimal upgrades for your existing PC, or choose the right new PC that fits your specific needs. This easy-to-use product gives you the same tools and knowledge that virtually every professional tester in the industry uses.

Below you can see all three scores, namely memory, CPU and total. Looking at the CPU score, which interests us more, the XE6800 is 22.02% faster than the E6600 and 50,23% faster than D930.

There's no real change in the order with the PC Mark 05 tests, and you wouldn't expect there to be. What is surprising though, in a nice way, is how much of a difference the Core 2 Duo processors make in the memory tests.

3DMark®06 is the worldwide standard in advanced 3D game performance benchmarking. A fundamental tool for every company in the PC industry as well as PC users and gamers, 3DMark06 uses advanced real-time 3D game workloads to measure PC performance using a suite of DirectX 9 3D graphics tests, CPU tests, and 3D feature tests. 3DMark06 tests include all new HDR/SM3.0 graphics tests, SM2.0 graphics tests, AI and physics driven single and multiple cores or processor CPU tests and a collection of comprehensive feature tests to reliably measure next generation gaming performance today.

Below we find both the CPU and total scores, where again the XE6800 is fastest.

7. Science Mark 2.0 ∧ Pov-Ray

Science Mark 2.0 is an attempt to put the truth behind benchmarking. In an attempt to model real world demands and performance, SM2 is a suite of high-performance benchmarks that realistically stress system performance without architectural bias. Science Mark 2.0 is comprised of 7 benchmarks, each of which measures a different aspect of real world system performance.

Pov-Ray is a high-quality, totally free tool for creating stunning three-dimensional graphics. It is available in official versions for Windows, Mac OS/Mac OS X and i86 Linux. The source code is available for those wanting to do their own ports. We used Pov-Ray 3.7beta15 for all tests, since it supports Dual Core CPUs. We used the built-in benchmark as suggested from the developers.

The Intel XE6800 was the fastest in these tests and in the POV Ray benchmark, it is more than double the performance of the D930.

- Nero Digital

One of the major advantages in having a Core2Duo processor can be witnessed in video encoding. Nero Digital is one of the better known Digital formats, offering both an ASP and AVC encoder.

For our tests, we used the latest version of Nero Recode, v2.3.1.8, as packaged in Nero Reloaded v7.5.0.1. As a source, we used a typical VOB file of 5mins duration. We encoded with each processor, in two modes (ASP, AVC) with exactly the same preferences (Same bitrate and Dual pass). The encoding time displayed below, is what Nero Recode reported. Obviously, the lower the time taken, the better. All results are displayed in seconds.

The Intel XE6800 does a fantastic job and encodes a 5min Mpeg4 AVC file in 491secs. That is about a fifth less the time taken by the E6600 and half the time of the Intel D930.

8. CINEBENCH

CINEBENCH is the free benchmarking tool for Windows and Mac OS based on the powerful 3D software CINEMA 4D. Consequently, the results of tests conducted using CINEBENCH 9.5 carry significant weight when analyzing a computer’s performance in everyday use.

Especially a system’s CPU and the OpenGL capabilities of its graphics card are put through their paces (even multiprocessor systems with up to 16 dedicated CPUs or processor cores). During the testing procedure, all relevant data is ascertained with which the performance of different computers can subsequently be compared, regardless of operating system. All tests were done with the latest available build (R9.5), and the sum of each subtest is displayed in the following chart..

This is the test in which the XE6800 and E6600 had their smallest difference, only 9.58%, while the IntelD930 performed 44.48% slower than the XE6800.

SuperPI has become an utility to benchmark modern systems. In August 1995, the calculation of pi up to 4,294,960,000 decimal digits was accomplished by using a supercomputer at the University of Tokyo. The program was written by D.Takahashi and he collaborated with Dr. Y.Kanada at the computer center, the University of Tokyo. This record-breaking program was ported to a personal computer environment such as Windows NT and Windows 95 and called Super PI.

The software offers up to 32M calculations of PI numbers. For our CPUs, we tested up to 8M calculations and summed the times taken at each stage for a total score.

The XE6800 again shows its teeth and for 1M+2M+4M+8M needs 5mins and 31.665secs. The E6600 comes close with 6mins and 29.501secs and lastly D930 needs a massive 12mins and 58.281secs. That's 15.54% faster than the XE6800 and 57.75% faster than the D930.

9. F.E.A.R.

The story begins as an unidentified paramilitary force infiltrates a multi-billion dollar aerospace compound. The government responds by sending in Special Forces, but loses contact as an eerie signal interrupts radio communications. When the interference subsides moments later, the team has been literally torn apart. As part of a classified strike team created to deal with threats no one else can handle, your mission is simple: Eliminate the intruders at any cost. Determine the origin of the signal. And contain this crisis before it spirals out of control.

The game offers up to 1280x960 resolution, which was used for all our tests. We maxed all details for the CPU and VGA card, except for AA/AF and Soft Shadows, which were enabled as shown in each graph. Below are the results after using the built-in benchmark test:

We were expecting to see greater differences between the three CPUs. However, the test results showed minor differences of only 2~4FPS.

- Prey

Prey tells the story of Tommy, a Cherokee garage mechanic stuck on a reservation going nowhere. His life changes when an otherworldly crisis forces him to awaken spiritual powers from his long-forgotten birthright. Abducted along with his people to a menacing mothership orbiting Earth, he sets out to save himself and his girlfriend and eventually his planet.

Prey is serious, dark story, based on authentic Cherokee mythology. Themes of sacrifice, love and responsibility are explored and the story dives into emotional territory not yet explored by similar games. Prey is based on Quake 3 engine and for sure will keep you awake many nights...

For all tests, we used hocbench, which offers all benchmarking options through a GUI. We used the built-in Guru3D timedemo and all results are posted below:

Again, very small differences between the three processors. This goes to show that generally, games software is almost entirely dependent on the graphics card.

10. Splinter Cell Chaos Theory

A Japanese Information Defense Force is formed to help face modern threats. Deemed a violation of international law and of the Japanese Post-War Constitution, Korea and China become outraged.

Secretly, the head of the IDF begins launching information-warfare attacks against Japan and blaming the attacks on North Korea. When the U.S. intervenes, as they are obligated to under Article 9 of the Japanese Post-War Constitution, the U.S. is attacked as well, forcing North Korea to escalate the situation with a pre-emptive invasion of South Korea.

As war erupts on the Korean Peninsula, Sam Fisher must thwart the alliance between the Japanese Admiral, a neurotic computer hacker, and the head of an international paramilitary company in order to prevent the rekindling of a massive world war in the Pacific.

The graphics engine supports Pixel Shader 3 and HDR, along with other new effects. We used hocbench which offers all benchmarking options through a GUI. We used the built-in "Guru3D 2" timedemo and all results are posted below:

The difference again is very small, with 28.3 vs 31 FPS for the Intel D930 and XE6800 respectively.

- Half Life 2 Episode 1

The world of Half-Life 2 has amazed everyone with its great story, graphics and Valve's great support. Half-Life 2: Episode One is the first in a series of new adventures created by Valve that extend the Half-Life 2 single player experience. It details the aftermath of Half Life 2 and launches a journey beyond City 17.

Stepping into the hazard suit of Dr. Gordon Freeman, you face the immediate repercussions of your actions in City 17 and the Citadel. Rejoin Alyx Vance and her robot, Dog, to once again aid the human resistance in their desperate battle against the totalitarian alien menace of the Combine.

Episode One exposes Alyx's combat skills and knowledge of City 17. Battle side-by-side with her through Valve's first episodic game, a four-to-six hour adventure of greater density and detail than non-episodic releases.

We recorded a timedemo and used the console to run each card with different visual quality settings. For all tests, we set the game to 1280x1024 with HDR shadows fully enabled.

Very small differences, even at the highest rendering modes with all 3 CPUs.

11. Overclocking - E6600

A lot of users will buy a CPU, only if it overclocks well. The Intel XE6800 and more especially the E6600, can overclock very well, provided that you have the proper motherboard and memory combination. Our tests were done with an Asus P5B Deluxe Wi-Fi edition motherboard. The motherboard offers a variety of tweaks that cannot be covered in this article however.

To sum up, the E6600 reached 2.40GHz (9x multiplier * 266.67Mhz FSB). The first and most obvious approach is with the multiplier locked at 9x, increase the FSB. From our tests, we managed to get a stable system at 9x350=3150MHz, running CPU and memory 1:1.

Below are several test results for the above overclocking. We squeezed an extra 750MHz from the E6600, which should allow it to overtake the XE6800, something that our results confirmed:

12. Overclocking - E6800

Moving on to the XE6800, the engineering sample we had could set the internal CPU multiplier to 13x, meaning that theoretically, the CPU could reach 13x * 266.67 = 3.46GHz. Despite our efforts, we didn't managed to get a stable system at that speed, even after raising the Vcore and Memory voltages.

Next we tried 12x multiplier, which, again didn't make for a stable system with our Asus P5B Deluxe Wi-Fi edition. The problem was that even we had set speedstep off in the BIOS, when the CPU load was high, the motherboard dropped the CPU voltage and therefore dropped performance. For that reason, we used Intel's 975DX motherboard that came with both samples and we got a fairly stable system running at 12x266.67 or 3.2GHz. CPU-Z identified the CPU as X6900, probably Intel will ship such product in upcoming months.

Below are several results after overclocking the XE6800. Note that due to different motherboards used, results aren't entirely "accurate", but they do give a ballpark indication...

Apart from only increasing the FSB, users can also lower the CPU multiplier. For example, with the E6600, from 9x to 8x and then further push the FSB higher, assuming it has proper memory. This again is a case of trial and error to get a stable, working system. We have seen reports of the E6600 reaching 3.6GHz :-)

13. Conclusion

The first Intel Core 2 Duo processor cores, codenamed Conroe are built on a 65 nm process and are intended for replacing the Pentium 4 and Pentium D series. Intel claims that the Conroe series provides 40% more performance at 40% less power, compared to the Pentium D. From our tests, we saw up to 55% performance difference in benchmarks and real life applications, comparing the Intel D930 and Intel Core2Duo XE6800.

The only difference between the E6600 and XE6800 Core 2 Duo models, is the clocked speed, where the E6600 is rated at 2.4 GHz, while the XE6800 at 2.93 GHz. The family has a 1066 MT/s front side bus, 4 MB shared L2 cache, and 65 watts TDP. There are two lower powered models, the E6300 and E6400 with 2MB L2 cache. Unfortunately, we didn't have the chance to test either of them and hence see the impact of a lower L2 cache.

The XE6800 is the fastest currently sold CPU from Intel. Apart from the various Intel technologies (Virtualization Technology, Execute Disable Bit, SSSE3, LaGrande Technology, Active Management Technology (iAMT2), it also supports the Enhanced SpeedStep Technology. This means that the XE6800 and E6600 can set their internal CPU multiplier and vary the running speed from 1600MHz up to 2937MHz. This is done automatically from Windows, or it can be disabled as well, provided that you have a compatible motherboard.

To sum up, the XE6800 is around ~ 19% faster than the E6600 average from all our tests. Their rating difference is around 22%, while , most importantly, the price difference is great. US$950 for the XE6800, and up to US$350 for the E6600. That's 172% higher price for only 19% faster performance. Don't forget that the E6600 showed much better overclocking capabilities than our XE6800 sample, reaching very easily 3.150GHz and overtaking the XE6800.

We have to note that Gamers who already have an Intel D9x0 CPU, don't have to buy Core2Duo to increase game frame rates. Our test results have shown that CPU has little impact on gaming. A better GPU or even the addition of a second VGA card (SLI or Crossfire), will bring higher gaming experience.

Ending our presentation of the Core2Duo CPU line, we feel that the E6600 is a wise choice for users who want affordable performance. It is also the perfect candidate for overclocking. At US$350, you get an ultra fast CPU, with the ability to outperform even the XE6800 with the proper tweaking.