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[nextpage title=”Introduction”]

We received from Intel a Core 2 Duo E6750 engineering sample, which is basically a Core 2 Duo E6700 with a 1,333 MHz FSB instead of 1,066 MHz. It will be launched later this summer together with several other Core 2 Duo models with the new 1,333 MHz FSB, and from the naming used on E6750 we can assume that Intel will use the number “50” on their model numbers to indicate the new external clock rate. Since we also had available a Core 2 Duo E6700 and a Core 2 Extreme QX6700 in our lab, we could make a terrific comparison between these three CPUs – as all three run internally at 2.66 GHz – to answer two basic questions: By how much the new 1,333 MHz FSB will improve PC performance? What is better, a quad-core CPU with 1,066 MHz FSB or a dual-core CPU with 1,333 MHz FSB? Read on.

Core 2 Duo E6750Figure 1: Core 2 Duo E6750 engineering sample.

The only difference between Core 2 Duo E6750 and Core 2 Duo E6700 is really the external clock rate: 1,333 MHz vs. 1,066 MHz. All other specs are the same, like the 4 MB L2 memory cache.

This new external bus works at 333 MHz transferring four data chunks per clock cycle, and that is why it is referred as 1,333 MHz (333 MHz x 4). In reality it doesn’t work at 1,333 MHz.

Core 2 Duo E6750Figure 2: Core 2 Duo E6750 specs.

Because this CPU is based on the new 1,333 MHz FSB, it requires a motherboard supporting this new FSB. So you won’t be able to install this or any other CPU based on the new 1,333 MHz external bus on older socket LGA775 motherboards, meaning that you probably won’t be able to upgrade your CPU with a new one by just replacing the processor, you will probably need to replace your motherboard as well.

Intel P35 and NVIDIA nForce 680i or 650i chipsets are some of the chipsets that support the new 1,333 MHz FSB. In our review we used a MSI P35 Platinum motherboard, which is based on the new Intel P35 chipset, but we faced a problem with this motherboard during our tests that we need to explain.

We were using DDR2-1066/PC2-8500 memories and we tried to keep them always running at 1,066 MHz, however this was only possible when the CPU external clock was of 1,066 MHz. With other clock rates the motherboard didn’t provide a memory clock multiplier that resulted in 1,066 MHz. With the FSB set at 800 MHz – which was necessary by our Pentium 4 3.4 GHz – the maximum clock rate we could set for our memories was also 800 MHz. For the Core 2 Duo E6750 we had the option to set our memories at 800 MHz, 1000 MHz, 1110 MHz or 1333 MHz. We tried to keep them at 1110 MHz but the system was unstable, thus we set them at 1000 MHz, 66 MHz below the clock rate they should be running at. This slight difference should not impact the final results.

In the table below we summarized below all CPUs included in this review with their main specs. We also added a column called “memory clock” for you to know the clock rate our memories were running when we collected data for each CPU – the clock rate below 1,066 MHz was a limitation from the motherboard we were using.

CPU Cores Internal Clock External Clock L2 Memory Cache Platform TDP Memory Clock
Core 2 Extreme QX6700 4 2.66 GHz 1,066 MHz (266 MHz x 4) 4 MB x 2 Socket LGA775 130 W 1,066 MHz
Core 2 Extreme X6800 2 2.93 GHz 1,066 MHz (266 MHz x 4) 4 MB Socket LGA775 75 W 1,066 MHz
Core 2 Duo E6750 2 2.66 GHz 1,333 MHz (333 MHz x 4) 4 MB Socket LGA775 65 W * 1,000 MHz
Core 2 Duo E6700 2 2.66 GHz 1,066 MHz (266 MHz x 4) 4 MB Socket LGA775 65 W 1,066 MHz
Pentium 4 550 1 3.4 GHz 800 MHz (200 MHz x 4) 1 MB Socket LGA775 115 W 800 MHz

* To be confirmed.

Unfortunately Intel didn’t provide us a Pentium D or a Pentium Extreme Edition samples for reviewing, and AMD seems to be out of samples and new high-end CPUs, because we haven’t received new samples from them for ages. A pity. If you’d like to see a comparison between the reviewed CPUs and Athlon 64 X2 5000+, please read our Core 2 Extreme QX6700 Review.

[nextpage title=”How We Tested”]

During our benchmarking sessions, we used the configuration listed below. Between our benchmarking sessions the only variable was the CPU being tested.
 
Hardware Configuration

Software Configuration

  • Windows XP Professional installed using NTFS
  • Service Pack 2
  • DirectX 9.0c

Driver Versions

  • NVIDIA video driver version: 158.22
  • Intel Inf chipset driver version: 8.3.0.1013
  • Audio driver version: Realtek R1.62
  • LAN driver version: Realtek 5.664.205.2007

Used Software

We adopted a 3% error margin; thus, differences below 3% cannot be considered relevant. In other words, products with a performance difference below 3% should be considered as having similar performance.

[nextpage title=”SYSmark2004″]

SYSmark2004 is a program that simulates the use of real-world applications. Thus, we consider this the best software to measure, in practical terms, the system performance.

The benchmarks are divided into two groups:

  • Internet Content Creation: Simulates the authoring of a website containing text, images, videos and animations. The following programs are used: Adobe After Effects 5.5, Adobe Photoshop 7.01, Adobe Premiere 6.5, Discreet 3ds Max 5.1, Macromedia Dreamweaver MX, Macromedia Flash MX, Microsoft Windows Media Encoder 9, McAfee VirusScan 7.0 and Winzip 8.1.
  • Office Productivity: Simulates the use of an office suite, i.e., simulates sending e-mails, word processing, spreadsheets, presentations, etc. The following programs are used: Adobe Acrobat 5.05, Microsoft Office XP SP2, Internet Explorer 6.0 SP1, NaturallySpeaking 6, McAfee VirusScan 7.0 and Winzip 8.1.

This software delivers several results, all of them using a specific SYSmark2004 unit. First we have a SYSmark2004 overall score. Then we have a group result for each batch listed above. And for each batch, we have specific results: 3D Creation, 2D Creation and Web Publication for Internet Content Creation; and Communication, Document Creation and Data Analysis for Office Productivity.

For a better visualization, we separated the results into three graphs: overall score, Internet Content Creation score and Office Productivity score.

Core 2 Duo E6750

SYSmark2004 – Overall

Score

Difference

Core 2 Extreme QX6700 (2.66 GHz) 

368

6.36%

Core 2 Extreme X6800 (2.93 GHz) 

367

6.07%

Core 2 Duo E6700 (2.66 GHz)

346

0.29%

Core 2 Duo E6750 (2.66 GHz)

345 

 

Pentium 4 550 (3.4 GHz) 

203 

70.44%

On the overall score Core 2 Duo E6750 achieved the same performance of Core 2 Duo E6700.

Core 2 Duo E6750

Difference Internet Content Creation 3D Creation 2D Creation Web Publication
Core 2 Extreme QX6700 (2.66 GHz) 14.16% 16.54% 16.22% 9.82%
Core 2 Extreme X6800 (2.93 GHz) 7.42% 9.27% 6.13% 7.30%
Core 2 Duo E6700 (2.66 GHz) -0.45% -1.25% -1.80% 2.02%
Pentium 4 550 (3.4 GHz) -48.09% -44.61% -48.29% -51.13%

Core 2 Duo E6750 achieved a performance similar to Core 2 Duo E6700 on Internet Content Creation score and in all of its individual tests. Here you can also see that Core 2 Extreme QX6700 had a good advantage because of its four cores, even though these three CPUs run at 2.66 GHz.

Core 2 Duo E6750

Difference Office Productivity Communication Document Creation Data Analysis
Core 2 Extreme X6800 (2.93 GHz) 5.22% 7.50% 6.43% 2.17%
Core 2 Duo E6700 (2.66 GHz) 0.75% 10.63% -4.83% -2.80%
Core 2 Extreme QX6700 (2.66 GHz) -0.75% 3.13% -2.14% -3.11%
Pentium 4 550 (3.4 GHz) -33.58% -15.00% -45.31% -37.27%

Core 2 Duo E6750 achieved the same performance level of E6700 on the Office Productivity score. However, on Communication Core 2 Duo E6700 was 10.63% faster, but this CPU was 4.83% slower than the reviewed CPU on Document Creation. On Data Analysis both CPUs achieved the same performance level. Here you can see that the extra cores brought by Core 2 Extreme QX6700 made no difference, as office applications do not take benefit of having more than two cores (or two CPUs) on the system. Thus the CPU with the highest clock – Core 2 Extreme QX6800 – was the fastest.

[nextpage title=”PCMark05 Professional”]

PCMark05 Professional measures the system performance by running several tests. We selected two batches for our comparisons, System and CPU.

The System batch performs the following tests: HDD XP Startup, Physics and 3D, 2D Transparent Window, 3D Pixel Shader, Web Page Rendering, File Decryption, 2D Graphics Memory – 64 lines, HDD General Usage and three multithreading tests.

The CPU batch performs the following tests: File Compression, File Decompression, File Encryption, File Decryption, Image Decompression, Audio Compression and two multithreading tests.

The results are given in a PCMark05 specific unit.

Core 2 Duo E6750

PCMark05 Professional 1.2.0 – System Batch Score Difference
Core 2 Extreme QX6700 (2.66 GHz) 8308 11.89%
Core 2 Extreme X6800 (2.93 GHz) 7803 5.09%
Core 2 Duo E6750 (2.66 GHz) 7425  
Core 2 Duo E6700 (2.66 GHz) 7334 1.24%
Pentium 4 550 (3.4 GHz) 4691 58.28%

Here Core 2 E6750 achieved the same performance level of Core 2 Duo E6700. Notice that we are using a newer version of PCMark05, which is now capable of taking advantage of more than two CPU cores, as now QX6700 achieved the highest score and on our previous tests Core 2 Extreme X6800 had been the fastest CPU on this program.

Core 2 Duo E6750

PCMark05 Professional 1.2.0 – CPU Score Difference
Core 2 Extreme QX6700 (2.66 GHz) 8619 25.73%
Core 2 Extreme X6800 (2.93 GHz) 7557 10.24%
Core 2 Duo E6750 (2.66 GHz) 6855  
Core 2 Duo E6700 (2.66 GHz) 6848 0.10%
Pentium 4 550 (3.4 GHz) 4097 67.32%

On PCMark05 CPU batch the same thing happened: Core 2 Duo E6750 achieved the same performance level as Core 2 Duo E6700.

[nextpage title=”Photoshop CS2″]

The best way to measure performance is by using real programs. The problem, though, is creating a methodology using real software that provides accurate results. For Photoshop CS2 there is a methodology created by the folks at GamingHeaven that is very accurate. Their script applies a series of 12 filters to a sample image and we wrote down the time taken for each filter to run. At the end, we have the results for each individual filter and we simply added them up to give the total time taken to run the 12 filters from GamingHeaven batch. The results below are given in seconds, so the lower the number the better.

Core 2 Duo E6750

Photoshop CS2 Seconds Difference
Core 2 Extreme X6800 (2.93 GHz) 123.5 9.59%
Core 2 Extreme QX6700 (2.66 GHz) 129.5 5.20%
Core 2 Duo E6700 (2.66 GHz) 132.9 2.71%
Core 2 Duo E6750 (2.66 GHz) 136.6  
Pentium 4 550 (3.4 GHz) 193.2 29.30%

Here once again Core 2 Duo E6750 achieved the same performance level as E6700.

[nextpage title=”Cinebench 9.5″]

Cinebench 9.5 is based on the 3D software, Cinema 4d. It is very useful to measure the performance gain given by having more than one CPU installed on the system when rendering heavy 3D images. Rendering is one area in which having more than one CPU helps considerably, because usually, rendering software recognizes several CPUs – Cinebench, for instance, can use up to 16 CPUs.

This software provides five results, Rendering 1 CPU, which measures the rendering performance using just one CPU, Rendering x CPUs, which measures the rendering performance using all CPUs available on the system, Cinema 4D shading, OpenGL Software Lighting and OpenGL Hardware Lighting. Since we were interested in measuring the rendering performance, we are going to compare the “Rendering x CPUs” results from all CPUs. Keep in mind that even though the Pentium 4 CPU we included in our review has only one core, it has Hyper-Threading technology, which simulates two CPUs.

Core 2 Duo E6750

Cinebench 9.5 Score Difference
Core 2 Extreme QX6700 (2.66 GHz) 1407 68.30%
Core 2 Extreme X6800 (2.93 GHz) 915 9.45%
Core 2 Duo E6750 (2.66 GHz) 836  
Core 2 Duo E6700 (2.66 GHz) 830 0.72%
Pentium 4 550 (3.4 GHz) 341 145.16%

Once more Core 2 Duo E6750 achieved the same performance level as Core 2 Duo E6700. As Cinebench is able to use up to 16 cores, the performance difference between QX6700 and E6750 was impressive.

[nextpage title=”3DMark06 Professional”]

3DMark06 is the latest version of 3DMark franchise, measuring Shader 3.0 (i.e., DirectX 9.0c) performance. We run this software on its default configuration (1280×1024 resolution with no image quality settings enabled) and besides the 3D score given by this program we also compared the results from its internal CPU benchmark.

Core 2 Duo E6750

3DMark06 Professional 1.1.0 Score Difference
Core 2 Extreme QX6700 (2.66 GHz) 10727 11.52%
Core 2 Extreme X6800 (2.93 GHz) 9841 2.31%
Core 2 Duo E6750 (2.66 GHz) 9619  
Core 2 Duo E6700 (2.66 GHz) 9618 0.01%
Pentium 4 550 (3.4 GHz) 5713 68.37%

Here once again Core 2 Duo E6750 achieved the same performance as Core 2 Duo E6700.

Core 2 Duo E6750

3DMark06 Professional 1.1.0 – CPU Score Difference
Core 2 Extreme QX6700 (2.66 GHz) 4246 76.18%
Core 2 Extreme X6800 (2.93 GHz) 2646 9.79%
Core 2 Duo E6700 (2.66 GHz) 2419 0.37%
Core 2 Duo E6750 (2.66 GHz) 2410  
Pentium 4 550 (3.4 GHz) 996 241.97%

Analyzing only the CPU score the results were the same: Core 2 Duo E6750 achieved a performance identical to Core 2 Duo E6700.

[nextpage title=”Far Cry”]

Far Cry is a heavy game based on the Shader 3.0 (DirectX 9.0c) programming model. We’ve updated the game to version 1.4. To measure the performance we run four times the demo created by German magazine PC Games Hardware (PCGH) and the results presented below are an arithmetic average of the collected data. We used the HardwareOC Far Cry Benchmark 1.8 utility to help us collecting the data.

We ran this game in two scenarios, both at 1600×1200. The first one, which we called “low”, was with no anti-aliasing, anisotropic filtering set to one and maximum details. The second one, which we called “high”, was with 8x anti-aliasing, 16x anisotropic filtering and ultra details. The results below are given in frames per second.

Core 2 Duo E6750

Far Cry 1.4 – Low FPS Difference
Core 2 Extreme X6800 (2.93 GHz) 151.09 7.59%
Core 2 Extreme QX6700 (2.66 GHz) 143.46 2.16%
Core 2 Duo E6700 (2.66 GHz) 141.18 0.53%
Core 2 Duo E6750 (2.66 GHz) 140.43  
Pentium 4 550 (3.4 GHz) 65.01 116.01%

On Far Cry with no image quality settings enabled once again Core 2 Duo E6750 achieved the same performance level of Core 2 Duo E6700.

Core 2 Duo E6750

Far Cry 1.4 – High FPS Difference
Core 2 Duo E6700 (2.66 GHz) 77.48 0.51%
Core 2 Extreme QX6700 (2.66 GHz) 77.45 0.47%
Core 2 Extreme X6800 (2.93 GHz) 77.25 0.21%
Core 2 Duo E6750 (2.66 GHz) 77.09  
Pentium 4 550 (3.4 GHz) 63.61 121.19%

When we maxed out image quality settings all Core 2 CPUs achieved the same performance level, indicating that when we max out the video quality settings is the video card that limits the maximum performance you can achieve.

[nextpage title=”F.E.A.R.”]

F.E.A.R. is a heavy game and we used its internal benchmarking module. We upgraded it to version 1.08 and measured performance in two scenarios, both at 1600×1200 with “computer settings” at “maximum”. The first one, we called “low”, was with “graphics card” set at “low”, and the second one, we called “high”, was with “graphics card” set at “maximum”. Let’s take a look at the results, given in frames per second.

Core 2 Duo E6750

F.E.A.R. 1.08 – Low FPS Difference
Core 2 Extreme X6800 (2.93 GHz) 273 2.25%
Core 2 Duo E6700 (2.66 GHz) 269 0.75%
Core 2 Duo E6750 (2.66 GHz) 267  
Core 2 Extreme QX6700 (2.66 GHz) 266 0.38%
Pentium 4 550 (3.4 GHz) 195 36.92%

On F.E.A.R. with image quality set to “low” all Core 2 CPUs achieved the same performance level, indicating that the video card is the component limiting the maximum performance you can achieve.

Core 2 Duo E6750

F.E.A.R. 1.08 – High FPS Difference
Core 2 Extreme QX6700 (2.66 GHz) 52 0.00%
Core 2 Duo E6700 (2.66 GHz) 52 0.00%
Core 2 Duo E6750 (2.66 GHz) 52  
Pentium 4 550 (3.4 GHz) 51 1.96%
Core 2 Extreme X6800 (2.93 GHz) 50 4.00%

When we changed the image quality settings to “maximum” all CPUs achieved the same performance level, indicating that the video card is the one limiting the maximum performance you can achieve.

[nextpage title=”Quake 4″]

We upgraded Quake 4 to version 1.4.2 and ran its new multiplayer demo id_perftest at 1600x1200x32 under two scenarios: first with image quality settings configured at “low” and then with image quality settings configured at “high”, both of them with SMP mode turned on through the command r_useSMP 1. You can check the results below, given in frames per second.

Core 2 Duo E6750

Quake 4 1.4.2 – Low FPS Difference
Core 2 Extreme X6800 (2.93 GHz) 194.27 0.67%
Core 2 Extreme QX6700 (2.66 GHz) 194.03 0.54%
Core 2 Duo E6700 (2.66 GHz) 193.30 0.17%
Core 2 Duo E6750 (2.66 GHz) 192.98  
Pentium 4 550 (3.4 GHz) 90.44 113.38%

On Quake 4 with image quality set at “low” all Core 2 CPUs achieved the same performance level, indicating that the video card is the one limiting the system performance.

Core 2 Duo E6750

Quake 4 1.4.2 – High FPS Difference
Core 2 Extreme X6800 (2.93 GHz) 186.32 0.46%
Core 2 Extreme QX6700 (2.66 GHz) 186.14 0.37%
Core 2 Duo E6700 (2.66 GHz) 185.86 0.22%
Core 2 Duo E6750 (2.66 GHz) 185.46  
Pentium 4 550 (3.4 GHz) 89.19 107.94%

When we set image quality to “high” the same thing happened.

[nextpage title=”Overclocking”]

Core 2 Duo E6750 works internally at 2.66 GHz multiplying its external clock by 8 (333 MHz x 8 = 2.66 GHz).

Unfortunately this engineering sample didn’t come with its clock multiplier unlocked, so we couldn’t increase its clock multiplier in order to have a preview of the performance of a Core 2 Duo with the new 1,333 MHz FSB working at 3 GHz (10 x 333 MHz) – i.e., we couldn’t preview the performance of Core 2 Duo “E6850”.

So we had no other option than increasing the processor external clock rate. During our tests we could put our Core 2 Duo E6750 running externally up to 379 MHz, what made it to run internally at 3.03 GHz, a 14% increase on its internal clock rate. We locked our memories with a 1:1.25 multiplier, what made them to run at 947.50 MHz.

With this overclocking the overall performance measured by PCMark05 increased 4.77% while the CPU score provided by this program increased 13.48%. On Quake 4 the performance remained the same.

We could set the external clock above 379 MHz, but the system was unstable. We only consider an overclock to be successful when we are able to run PCMark05 and Quake 4 four times without crashing.

Overclocking success depends a lot on the motherboard and on the CPU used. Even between two identical CPUs one can reach a higher overclocking than the other, especially if they are from different production batches.

We didn’t play with any fancy configuration, like increasing the CPU voltage. Thus with more time and patience you will probably achieve a better overclocking with Core 2 Duo E6750 than we did.

[nextpage title=”Conclusions”]

On all our tests Core 2 Duo E6750 performance was identical to Core 2 Duo E6700, even though it uses a faster front side bus – and we simulated the use of several different types of application.

So what is the advantage of using a Core 2 Duo E6750 instead of a Core 2 Duo E6700? Based on the results from our tests, none.

Then why Intel is launching this new 1,333 MHz external bus? We have two answers for that.

First, on quad-core CPUs the higher external clock rate may increase the system performance. This happens because currently on Intel quad-core CPUs the cores are arranged into two pairs. The cores inside each pair can talk directly to each other, but if they need to talk to a core that belongs to the other pair they need to go to the front side bus and make this connection going through outside the processor. Increasing the CPU external clock rate increases, at least in theory, the speed each core pair can talk to each other. For a detailed explanation about this subject please read our Intel Quad Core Overview and Roadmap article.

We will have to wait until we review a quad-core CPU based on this new FSB to see if this is really the case.

The second reason we can see is regarding DDR3-1333 memories, which will be supported by the Intel X38 chipset to be launched in July. Using DDR3-1333 memories with a Core 2 running externally at 1,333 MHz you will be able to match the FSB clock with the memory clock, allowing you to achieve the maximum performance with current technology.

In retrospect we must keep in mind that this is the first time in six years that Intel is launching a new front side bus speed with memories matching it. When the Pentium 4 was launched, for example, it used the then-new 400 MHz FSB and there were no 400 MHz memories at the time – this was PC-100 times and DDR-400 wasn’t available yet. The same thing happened when they launched the 533 MHz, the 800 MHz and even the 1,066 MHz external clock speeds. Even to this date Intel chipsets do not officially support DDR2-1066 (even though Intel P965 and P35 can access memories at 1,066 MHz just fine and P35 officially support DDR3-1066). DDR3-1333 availability may be an issue, but that is a totally different story.