Core i5-661 CPU Review
By Gabriel Torres on January 5, 2010
Many years ago, experts predicted that in the future computer processors would have an integrated graphics processor, instead of having this component on the motherboard chipset or on a discrete graphics card. In fact, AMD was the first CPU manufacturer to announce the development of such solution, dubbed Fusion. However, it is its competitor, Intel, the first company to launch products using this idea (codenamed “Clarkdale”). Today we are going to review one of the first CPUs with an integrated graphics processor (GPU) to arrive on the market, Core i5-661.
One of the main features introduced with socket LGA1156 processors was a PCI Express 2.0 x16 controller inside the CPU. The most obvious speculation for this move was to allow the release of CPUs with an integrated graphics controller. Whoever speculated that this would come true was right.
What came as a surprise to us was the release of Core i5 CPUs using this technology. Usually integrated graphics is reserved for entry-level computers, and our best bet was that only the new entry-level CPU from Intel, Core i3, would carry an integrated graphics controller.
Intel is announcing this week six new desktop processors, four Core i5 and two Core i3, all with integrated graphics. Since the only Core i5 CPU released to date, Core i5-750, doesn’t have an integrated graphics controller and starts with the model number “7,” it is safe to assume that all Core i5 models starting with “6” have an integrated graphics controller. The models ending with “0” have this embedded graphics chip running at 733 MHz, while models ending with “1” have this component running at 900 MHz, which is the case of the model we are going to review. This rule also applies to Core i3 models. On the slide below we show the main specs of these new CPUs.
As you can see, all Core i3 and Core i5 models being released are dual-core CPUs with Hyper-Threading technology, meaning that the operating system recognize them as if they had four cores (Hyper-Threading technology emulates an additional core per CPU core; this emulated core is slower than a real core, of course). Core i5-750 is a quad-core CPU without Hyper-Threading technology. So while all Core i5 CPUs are recognized as having four processing cores by the operating system, on Core i5-6xx only two of them are “real” (the other two are emulated). Thus another difference between Core i5 models starting with “6” is the presence of two cores with Hyper-Threading technology, while models starting with “7” come with four cores but not Hyper-Threading.
Another important difference is that these new Core i5 CPUs have half the amount of L3 memory cache compared to Core i5-750 (4 MB vs. 8 MB). All other caches remain with the same size (32 KB + 32 KB for L1 and 256 KB for L2, per core).
Core i5 CPUs feature Turbo Boost technology, which allows the CPU to increase its clock when the computer demands for more processing power (as long as its temperature stays within the normal range, i.e., up to the processor’s TDP). We reviewed Core i5-661 with this feature enabled; this CPU runs officially at 3.33 GHz but when Turbo Boost is enabled it can overclock itself up to 3.60 GHz.
Like Core i5-750, all these new CPUs have an embedded memory controller supporting DDR3 memories up to 1,333 MHz under dual-channel configuration.
New motherboards are necessary for these new CPUs, since motherboards based on the previous socket LGA1156 chipset, P55, don’t have the necessary video connectors. Three new chipsets were released for these new CPUs: H57, H55 and Q57. The differences between these chipsets and a comparison with P55 are provided in Figure 2.
All these new CPUs are built using the new 32-nm manufacturing process (the previous Core i5 is manufactured under 45-nm technology), codenamed “Westmere.” One of the main novelties brought by this new process is the introduction of six new instructions targeted to encryption (called AES-NI or Advanced Encryption Standard New Instructions).Now let’s see the features of the new integrated graphics controller.
The integrated graphics controller found on the new Core i5 and Core i3 CPUs is a DirectX 10 part running at 733 MHz (models ending in “0”) or 900 MHz (models ending in “1”) with 12 processing engines (“shader units”). A complete comparison between the integrated graphics controller found on these new CPUs and the graphics controller embedded on the Intel G45 chipset can be seen on Figures 3 and 4.
We decided to compare Core i5-661 (3.33 GHz) to Core i5-750 (2.66 GHz) because they both come with the exact same price tag (USD 196). We wanted to include a competitor from AMD, and the CPU that AMD offers on this price range is Phenom II 965 Black Edition (USD 195). All these prices are quoted in 1,000 quantities for distributors in the USA.
We installed the CPU from AMD on a motherboard with integrated graphics (AMD785G). And with all these CPUs we installed a mainstream video card (GeForce 9600 GT) to see how (and if) it would improve performance.
Although we installed Core i5-750 on the same motherboard as Core i5-661, integrated video isn’t available, as this CPU doesn’t have this feature and with socket LGA1156 the integrated video is produced by the CPU and not by the motherboard like on other platforms.
Phenom II X4 965
32 KB + 32 KB per core
256 KB per core
4 MB total
DDR3 up to 1333 MHz
32 KB + 32 KB per core
256 KB per core
8 MB total
DDR3 up to 1333 MHz
Phenom II X4 965
64 KB + 64 KB per core
512 KB per core
6 MB total
DDR3 up to 1333 MHz
TDP stands for Thermal Design Power which advises the user of the maximum amount of heat the CPU can dissipate. The CPU cooler must be capable of dissipating at least this amount of heat.
The prices listed are the official prices for distributors based on 1,000 quantities. The end-user price is higher than the prices listed.
A quick comparison between the integrated video from Core i5-661 and AMD785G (used with Phenom II X4 965 in our tests) is provided below.
During our benchmarking sessions, we used the configuration listed below. Between our benchmarking sessions the only variable was the CPU being tested and the motherboard, which had to be replaced to match the different CPU sockets.Hardware Configuration
Operating System Configuration
Driver Versions – Intel
Driver Versions – AMD
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.
PCMark Vantage simulates the use of real-world applications and gives scores for the following categories:
For a detailed description of each one of these tests, please download and read the PCMark Vantage Reviewer’s Guide.
You can see the results for each category below. We are not going to compare the results for the Memories and HDD suites.
Core i5-661 achieved an overall PCMark score 23% higher than Phenom II X4 965 with integrated video. Core i5-750 with a GeForce 9600 GT achieved the same performance level of the Core i5-661 using its integrated video. When we installed a GeForce 9600 GT with this CPU performance increased 6%, making it to be 4% faster than Core i5-750 and 16% faster than Phenom II X4 965, also with a GeForce 9600 GT installed.
On the TV and Movies benchmark Core i5-661 achieved the same performance level as Phenom II X4 965 with integrated video. A Core i5-750 with GeForce 9600 GT was 10% faster than Core i5-661 with integrated video. When we installed a GeForce 9600 GT performance increased 11%, making it to achieve the same performance level as Phenom II X4 965 and Core i5-750 with the same video card installed.
On the Gaming set the integrated video from Core i5-661 achieved a far higher performance (19% higher) than the integrated video from AMD 785G with a Phenom II X4 965. Installing a GeForce 9600 GT made the performance to increase 88%, showing how fast a GeForce 9600 GT is compared to this CPU integrated video. With this video card installed, Core i5-661 achieved the same performance level as Core i5-750, being 34% faster than Phenom II X4 965.
On the Music benchmark Core i5-661 achieved a performance a little bit (3%) higher than Phenom II X4 965 with integrated video and on the same level as Core i5-750 paired with a GeForce 9600 GT. Installing a GeForce 9600 GT increased performance a tiny bit (1.46%, which is statistically irrelevant), making all three CPUs to achieve the same performance level.
On the Communications tests we saw an impressive advantage to the new Core i5-661. Using its integrated video it was 43% faster than Phenom II X4 965 (with AMD 785G) and 52% faster than Core i5-750 (with GeForce 9600 GT). Installing a GeForce 9600 GT didn’t improve Core i5-661 performance, and under this scenario it was 35% faster than Phenom II X4 965 with the same video card installed.
And finally on the Productivity benchmark Phenom II X4 965 with integrated video was a little bit faster than Core i5-661 (4%). Installing a GeForce 9600 GT made all three CPUs to achieve the same performance level.
With VirtualDub we converted a full-length DVD movie to DivX format and saw how long it took for this conversion to be completed. The DivX codec is capable of recognizing and using not only more than one CPU (i.e., more than one core), but also the SSE4 instruction set.
The movie we chose to convert was Star Trek – The Motion Picture: Director’s Cut. We copied the movie to our hard disk drive with no compression, so the final original file on our HDD was 6.79 GB. After compressing it with DivX, the final file was only 767.40 MB, which is quite remarkable.
The results below are given in seconds, so the lower the better.
On DivX encoding Phenom II X4 965 with AMD 785G was 8% faster than Core i5-661 and Core i5-750 with GeForce 9600 GT was 21% faster. Installing a GeForce 9600 GT didn’t make any impact on performance for Core i5-661, but interesting enough Phenom II X4 965 was 7% faster when using its on-board video instead of a GeForce 9600 GT.
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 CS4, there is a methodology created by the folks at GamingHeaven that is very accurate. Their script applies a series of 15 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 have the total time taken to run the 15 filters from the GamingHeaven batch. The results below are given in seconds, so the lower the number the better.
On Photoshop CS4 Core i5-661 was 16% faster than Phenom II X4 965 (comparing both results with the integrated video) and 8% faster than Core i5-750 (with a GeForce 9600 GT). Installing a GeForce 9600 GT didn’t make any difference in performance for both Core i5-661 and Phenom II X4 965.
After Effects is a very well-known program for video post-production that is used to add animation and visual effects in videos. To evaluate the performance of each CPU running this program, we ran a workload consisting of 25 compositions that applied several filters and effects to a variety of input file types such as PSD (Photoshop), AI (Illustrator), EPS, and TIF. After each filter was applied, the composition was rendered to an uncompressed AVI file with the same resolution as the input files. The results below are the time each CPU took to finish the whole batch, given in seconds, so the lower the number the better.
On After Effects CS4 Core i5-661 was 30% faster than Phenom II X4 965 with AMD 785G, but Core i5-750 with a GeForce 9600 GT was 23% faster. Installing a GeForce 9600 GT didn’t improve Core i5-661’s performance, but did improve Phenom II X4 965’s by 28%, making it to achieve a performance similar to Core i5-661 under this scenario.
We measured the time each CPU took to compress five high-resolution 48-bit uncompressed TIF images, each one with around 70 MB, to RAR format with the popular WinRAR application. The results below are given in seconds, so the lower the number the better.
File compression was 17% faster on a Phenom II X4 965 with AMD 785G than with a Core i5-661 and its integrated graphics. Core i5-750 was 40% faster on file compression than Core i5-661. Installing a GeForce 9600 GT didn’t improve performance here.
Cinebench 10 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.)
Since we were interested in measuring the rendering performance, we ran the test called “Rendering x CPUs,” which renders a “heavy” sample image using all available CPUs (or cores – either real or virtual, as on CPUs with Hyper-Threading technology, each core is recognized as two cores by the operating system) to speed up the process.
On Cinebench Phenom II X4 965 was 28% faster than Core i5-661, both with integrated video. This was expected, as Phenom II X4 is a quad-core CPU, while Core i5-661 is a dual-core CPU with Hyper-Threading technology. Core i5-750 was 33% faster than Core i5-661 for the same reason. Installing a GeForce 9600 GT didn’t improve performance, as expected.
3DMark Vantage measures Shader 4.0 (i.e., DirectX 10) gaming performance. We ran this program under the default profile, called “performance.”
The integrated video from AMD 785G could not run this program.
A GeForce 9600 GT proved to be 81% faster than the integrated video from Core i5-661. With a GeForce 9600 GT installed, Core i5-661 was 9% faster than Core i5-750 and 15% faster than Phenom II X4 965, also showing us that GeForce 9600 GT is still very dependent on the performance from the CPU.
Half-Life 2 is a popular franchise and we benchmarked the video cards using Episode Two with the aid of HOC Half-Life 2 Episode Two benchmarking utility using the “HOC Demo 1” provided by this program. We ran the game under 1024x768 with no anti-aliasing and bilinear filtering, i.e., using the lowest image quality possible. The results, given in frames per second, you see below.
On Half-Life 2: Episode Two the integrated graphics from Core i5-661 was 20% faster than AMD 785G’s with a Phenom II X4 965. A GeForce 9600 GT proved to be 185% faster than the integrated graphics from Core i5-661. With this video card installed Core i5-750 was 45% faster and Phenom II X4 965 was 39% faster.
Also notice how we got around 48 frames per second with the integrated video from Core i5-661: though not the best in the world, this performance level at least allows you to play this game with all image enhancements disabled.
Fallout 3 is based on the same engine used by The Elder Scrolls IV: Oblivion, and it is a DirectX 9.0c (Shader 3.0) game. We configured the game with “low” image quality settings at 1440x900. To measure performance, we used the FRAPS utility utility running an outdoor scene at God mode, running through enemy fire, triggering post processing effects, and ending with a big explosion in front of Dupont Circle.
The integrated video from Core i5-661 could not run this game.
Comparing the results with a GeForce 9600 GT installed, all CPUs achieved the exact same performance level.
The new Core i5-661 is certainly an interesting CPU. It beats Phenom II X4 965 with AMD 785G in almost all tests we performed. However on applications capable of using four CPUs, the CPU from AMD was faster: file compression with WinRAR, DivX encoding and 3D rendering with Cinebench. In some scenarios it even beats Core i5-750 due to its higher clock rate. We didn’t, however, evaluate video quality for 2D video playback, so we have no opinion on that.
Its integrated video performs satisfactorily for a user looking for a computer with integrated video and that knows the limitations of this kind of system. We could run older games relatively well with image quality settings disabled, performing better than AMD 785G. But some newer games won’t even run, as it happened with Fallout 3.
If you run games that don’t take advantage of four CPU cores (most of them) you can buy Core i5-660 or Core i5-661 to run with a discrete mainstream video card: they cost the same as Core i5-750 but because of their higher clock rate (3.33 GHz vs. 2.66 GHz) they perform better. With high-end video cards the scenario is a little bit different, as usually with them the CPU does not impact a lot on gaming performance.
The only real drawback we see with Core i5-661 is its price for the user looking for an integrated-video solution. At USD 200 range it will hardly be in the list of the kind of people that usually look for a CPU for a system with integrated video (the Intel DH55TC motherboard alone will cost another USD 100), but it can be an interesting option if you want a computer with a strong mainstream CPU and it is not into games or plan to install a real video card in the future and won’t be needing a real quad-core CPU. If, however, you mostly run applications like video editing and 3D rendering, then Core i5-750 with a discrete video card is a better option, though the system will be more expensive, since it will require you to buy a video card.