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Clarkdale's Efficiency: Core i5-661 Versus Core 2, Athlon II, And Phenom II
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1. Clarkdale Efficiency Analyzed

Intel’s new Core i3 and i5 dual-cores arrived with a bang, offering more performance than the Core 2 Duo family they’ll eventually replace. The integration of a graphics unit into the processor may be a key enabler to maximizing efficiency of LGA 1156 systems, but just how much more efficient is Intel’s new platform? We grabbed an H55-based motherboard and the Core i5-661 (centering on the Clarkdale core) to compare with Intel's Core 2 Duo E8600 and G45 chipset. We also compared against an AMD 785G-based system running both an efficient Athlon II X2 240e and the fast Phenom II X2 550 Black Edition.

Intel is working towards greater integration. The H55/H57/Q57 platforms with Core i3/i5 Clarkfield CPUs now move the graphics unit and the memory controller out of the chipset and into the processor. The memory controller was already relocated on the Core i7 (Bloomfield) in the high-end market and Core i5/i7 (Lynnfield) in the upper-mainstream. The low-end Atom platform also follows with next-generation Pine Trail, which also transitions the platform from three to only two chips. Today, though, Intel is focused on the lucrative mainstream desktop and mobile segments. For purposes here, we’ll concentrate on the desktop side.

Our technology launch article by Chris Angelini already covered all aspects of the new processors, such as the integrated HD Graphics unit, Turbo Boost in the context of integrated graphics, the additional instructions to accelerate AES encryption and decryption, and specifications and clock speeds. Now it’s time to have a closer look at system power consumption and efficiency in terms of performance per watt. Intel now has its 32nm silver bullet, which should make the dual-cores much more efficient at base clock rates. Most people expected Intel’s new dual-cores to dominate in efficiency, but we wanted to have a close look at the power characteristics.

2. Intel’s Clarkdale Processors

The new processors are available for desktops (Clarkdale) and mobile PCs (Arrandale). However, in this article we will only be talking about desktop solutions.

There are three major changes from the prior generation. First, Intel transitioned from the 45nm to 32nm CMOS process. Secondly, all new Core i5 and Core i3 processors have two processing cores, unlike the existing Core i5 and i7 processors, which are all quad-core designs. The dual-core offerings are designed to bring the LGA 1156 platform down to mainstream price points. Lastly, all Core i5 and i3 processors with two cores come with Intel’s integrated HD Graphics. You may use the CPUs with an H55, H57, or Q57 motherboard, or you can opt for discrete graphics, dropping the chips into P55 systems.

Another Dual-Die Processor

According to Olaf Höhne, client marketing manager for Intel and spokesperson at Intel’s 2010 Core processor presentation in Germany, the 32nm CPU was originally intended to be a 45nm part. Thanks to fast advances on the new manufacturing technology, Intel obviously decided to push up the new process technology. Intel first had its Pentium D (Presler) CPU combine two separate silicon dies within a single chip. The company did the same with the quad-core Kentsfield (65nm) and Yorkfield (45nm). While many people criticized the Core 2 Quad for not being a “native” monolithic quad-core, the results were still competitive, to say the least. Intel typically prefers economic decisions over popular ones.

The TDP Game

Intelligent Power Sharing allows both the processor and the graphics core to utilize the thermal envelope as much as necessary.

Graphics and processor together add up to a total Thermal Design Power (TDP) that can be dynamically adjusted. Once again, Intel implemented its Turbo Boost technology to allow the processor to accelerate the clock speed by several bins. This load-dependant clock selection is technically also available for the graphics unit, but Intel decided to only activate HD Graphics with dynamic frequency for its mobile platforms. Although the decision makes sense from a positioning standpoint, this would have been a nice addition for desktop platforms. Turbo Boost works on all of the Core i5 dual-core models, but it’s not available on the Core i3 series. Hyper-Threading, which provides two virtual cores per physical core to the operating system, is available on all Core i5 and i3 processors, but not the latest Pentium G6950.

Core i3/i5 Processor Models

ProcessorBase ClockTurbo BoostCores / ThreadsL3 CacheGraphicsMemory SupportTDPInitial 1Ku Pricing
Core i5-670
3.46 GHz3.73 GHz2/44MB733 MHzDDR3-133373W$284
Core i5-661
3.33 GHz3.60 GHz2/44MB900 MHzDDR3-133387W$196
Core i5-660
3.33 GHz3.60 GHz2/44MB733 MHzDDR3-133373W$196
Core i5-650
3.20 GHz3.46 GHz2/44MB733 MHzDDR3-133373W$176
Core i3-540
3.06 GHz-
2/44MB733 MHzDDR3-133373W$133
Core i3-530
2.93 GHz-
2/44MB733 MHzDDR3-133373W$113


Although Pentium-class 32nm processors will cover the low-end, the minimum speed for Core i3/i5 is as high 2.93 GHz—significantly more than before, and more than enough for everyday applications. Core i5 processors with Turbo Boost can speed up to 3.46, 3.6, and 3.73 GHz, depending on the processor model.

3. Intel's Core i5-661 (Clarkdale) CPU

The Core i5-661 is a unique model from Intel with the family's fastest graphics clock. Its HD Graphics unit runs at 900 MHz, as opposed to the 733 MHz found on all other Core i3/i5 processors. Other than that, there are no differences between the models. All HD Graphics cores have 12 EUs (Execution Units) with Intel third-generation shaders. DirectX support is still limited to 10.0, but OpenGL support was upgraded from 2.0 to 2.1. Due to the 661’s higher graphics speed, the whole package's TDP is higher, as well, reaching up to 87W versus 73W on all other Core i3/i5 models.

Remember that the TDP applies to both to the processor and the graphics unit, which was formerly part of the chipset. Despite the slightly higher TDP, Intel says that the entire ecosystem of coolers and platforms for 65W processors can also be used for the 73W parts, which is significant in helping to keep platform costs lower. Base and Turbo Boost speeds for the Core i5-661 are identical to the Core i5-660 as well.

The new Core i3 and i5 dual-cores are not identical to the Core i5 and i7 quad-cores. Intel took a clue from VIA and added a new feature that we found to be extremely powerful: an AES engine. Clarkdale supports a set of six additional instructions designed to accelerate FDE (full disk encryption), file encryption, Internet security, and voice-over-IP applications. As you will see in the synthetic benchmarks, these modifications make a dramatic difference in PCMark Vantage’s encryption tests.

 

4. Clarkdale Platform: H55 (Intel DH55TC)

Intel's press kit for this launch consisted of Core i5-661 processors and the DH55TC microATX desktop motherboard with its H55 chipset. We used this board for the efficiency evaluation, since we haven’t had the chance to look at enough H55/H57 options.

First, a little chipset update: H55 is the base model for LGA 1156 platforms with integrated graphics, offering 12 USB 2.0 ports, HD Audio, gigabit LAN, six SATA/300 ports with AHCI, and six PCIe 1.1 ports. The H57 takes all this and adds two more USB 2.0 ports, two more PCIe lanes, and RAID capabilities. Finally, there is Q57, the professional version that comes with Active Management Technology and Trusted Execution Technology options.

This motherboard is positioned in Intel’s Media Series, aimed at all sorts of digital home PCs up to HTPC solutions. It offers one 15-pin D-sub analog port, one DVI-D, and one HDMI. You can plug a discrete graphics card into the x16 PCI Express 2.0 slot; this will switch off the integrated graphics unit. Switcheable graphics, available on mobile platforms built with the Arrandale CPUs, is not possible on the desktop.

The board implements five-phase switching voltage regulators, which include solid capacitors, but only for the processor voltage circuits. Four DIMM sockets will accept up to 16GB of DDR3 memory at DDR3-1333 or 1066 speeds. Overclocking is, in fact, supported on this motherboard through the use of BCLK frequency adjustments and memory multiplier overrides. However, voltage increases are not supported, which will likely limit how far you can take most LGA 1156 processors. The six SATA/300 ports do not support RAID of any sort, including RAID 0 or 1; for these, you'd need a platform centering on the H57 Express chipset. Being essentially mandatory these days, gigabit Ethernet networking and multi-channel HD audio (5.1+2-channel multi-stream, in this case) are also on-board.

Parallel and serial ports are supported, but not routed to the ATX connector panel. Instead, you’ll have to obtain and add the necessary connectors yourself. Six of the total 12 USB 2.0 ports are instantly available; the others can be added through integrated port headers. There is a combined PS/2 port for either a mouse or a keyboard. Lots of unused space in the connector panel could have been used for an eSATA port, digital audio connectors, or more USB ports, but Intel decided to keep a very low profile with this board.

5. Lining Up The Competition: AMD Athlon/Phenom II X2 And Intel Core 2 Duo

AMD Phenom II X2 550

Of course, we had to use AMD’s fastest dual-core desktop processor for comparison with the Core i5. This is currently the Phenom II X2, now available at 3.1 GHz and 3.0 GHz clock speeds. Chris Angelini reviewed the Phenom II X2, code-named Calisto, in June of 2009. Calisto is the dual-core version of the triple-core “Heka” (Phenom II X3) and quad-core “Deneb” (Phenom II X4). As a result, the 6MB L3 cache is still available, only now for two cores. A 512KB L2 cache sits in each core, along with a DDR3-1333 dual-channel memory controller. The cores still support DDR2, as well, so users with Socket AM2+ motherboards can install AM3-based Phenom II processors with a suitable BIOS update. All Phenom II processors are fabricated using Global Foundries’s 45nm SOI process.

We used a Phenom II X2 550, the 3.1 GHz top model. AMD introduced a C3 stepping for its Phenom II X4 processors a few months ago. Don Woligroski compared the C2 and the C3 stepping on Phenom II X4 965 Black Edition processors, where it made a small difference on power consumption. AMD’s site doesn’t list C3 steppings for the Phenom II X2 yet, but we trust this will show much lower power consumption.

Since we expected the new Core i5 to deliver excellent power efficiency, we decided to add a second AMD processor to the test bed.

AMD Athlon II X2 240e

Several energy-efficient processors have been suffixed with an “e.” In this case, we picked an Athlon II X2 processor based on the Regor dual-core design. The same would be available with three cores (Athlon II X3, Rana) or as a quad-core (Athlon II X4, Propus). All three are based on 45nm technology and very similar to the Phenom II. The only significant difference is the L3 cache, which doesn’t exist on Athlon II processors. AMD has a low-power Athlon II X4 605e at 2.3 GHz, a 405e X3 at 2.3 GHz, and the 240e dual-core that we used for this review. The latter runs at 2.8 GHz, and although all e-models are specified at 45W TDP, it’s obvious that the dual-core is lowest on power consumption.

Intel Core 2 Duo E8600

Finally, there is Intel’s fastest Core 2 Duo model, the E8600. We initially reviewed the 45nm Core 2 Duo processor (Wolfdale) almost two years ago when it was still limited to 3.16 GHz (E8500). The top model E8600 was introduced later that year, and despite many rumors, there hasn’t been an official E8700 at 3.46 GHz. Hence, the 3.33 GHz E8600 remains the top of Intel's Core 2 Duo family, which we used for this comparison. Core 2 Duo processors all support Enhanced SpeedStep technology, which reduces the clock speed in idle to the base clock times a 6x multiplier, which typically results in 333 MHz x 6 = 2,000 MHz. Therefore, more Core 2s would show similar idle power, but differ in peak power due to varying clock speeds.

The Wolfdale core comes with a large 6MB L2 cache, which is shared by both cores. The thermal envelope has remained at 65W, and there haven’t been any low power models. However, this core is also used to create four-core processors. Two Wolfdale die in a physical processor result in Yorkdale, also known as Core 2 Quad. Intel has had low-power models in this family, known as S-models (for example, the Core 2 Quad Q8200S). However, these have been rather expensive and only attractive for specific applications.

6. AMD Platform: 785G (Gigabyte MA785GMT-UD2H)

The AMD 785G chipset is AMD’s latest mainstream desktop core logic with integrated graphics. Don Woligroski reviewed it almost half a year ago, and it’s been a popular choice for HTPC setups and multimedia PCs, largely because mainstream AMD processors and their compatible motherboards are so much cheaper than Intel-based equivalents. One AMD advantage is that its advanced graphics core supports DirectX 10.1, which Intel still doesn’t.

We used Gigabyte’s MA785GMT-UD2H motherboard, based on the 785G and SB710 chipset. The southbridge offers five internal SATA/300 ports with basic RAID support (no RAID 5) and one eSATA port for external storage. There’s still one UltraATA/133 channel, which can be handy for keeping optical or IDE-based hard drives afloat. Gigabyte adds HD Audio support, a FireWire 1394a controller with one installed port, gigabit networking, and the full line of differentiating features, including DualBIOS and UltraDurable 3 technology. This entails using extra copper to reduce resistance and increase signal quality. All AMD processors with up to a 140W TDP are supported through five-phase voltage regulation.

7. Intel Platform: G45 (Intel DG45ID)

Finally, we also needed a G45 motherboard, which represents Intel’s previous-generation platform with integrated graphics. Since we used an H55 motherboard from Intel, it made sense to select a similar product with the preceding chipset.

The DG45ID is also a Media Series motherboard, but it’s better-equipped than the DH55TC. In addition to all of the standard chipset features, Intel adds a FireWire 1394a controller, makes one SATA port available as eSATA, and adds optical audio output. This product doesn’t have an analog D-sub display port, but it still has the more important DVI and HDMI connectors. Intel only has three phases on the voltage regulator, which would be insufficient to run Extreme Edition processors properly, but all mainstream dual- and quad-core CPUs should do just fine. Like the new DH55TC, this motherboard isn’t much of an overclocker, but it works well for office and home PCs and entry-level media centers.

8. Test Setup
System Hardware
HardwareDetails
Motherboard I
(Socket AM3)
Gigabyte MA785GMT-UD2H (Rev. 1.0)
Chipset: AMD 785g
BIOS: F4a (11/03/2009)
Motherboard II
(LGA 775)
Intel DG45ID (Rev. 1.0)
Chipset: G45
BIOS: 0089
Motherboard III
(LGA 1156)
Intel DH55TC  (Rev. 1.0)
Chipset: H55
BIOS: 0027 (11/19/2009)
CPU AMD IAMD Athlon II X2 240e (45nm, 2.8 GHz, 2 x 1MB L2 Cache, TDP 45W, Rev. C2)
CPU AMD IIAMD Phenom II X2 550 (45nm, 3.1 GHz, 2 x 512KB L2 and 6MB L3 Cache, TDP 80W, Rev. C2)
CPU Intel IIntel Core 2 Duo E8600 (45nm, 3.33 GHz, 4 x 6MB L2, TDP 65W, Rev. C2)
CPU Intel IIIntel Core i5-661 (32nm, 3.33 GHz, 2 x 256KB L2 and 4MB L3 Cache, TDP 87W)
RAM DDR2 (dual)2 x 2GB DDR2-1066 (Walton Chaintech Apogee AU2G732-12GH001)
RAM DDR3 (dual)2 x 2GB DDR3-1600 (Corsair CMD4GX3M2A1600C8)
Hard DriveWestern Digital VelociRaptor, 300GB (WD3000HLFS)
10,000 RPM, SATA/300, 16MB Cache
Power SupplyPC Power & Cooling, Silencer 750EPS12V 750W
System Software & Drivers
Operating SystemWindows Vista Enterprise Version 6.0 x64
Service Pack 2 (Build 6000)
Drivers and Settings
AMD Graphics DriversATI Catalyst 9.11
AMD Chipset DriversATI Catalyst 9.11
Intel Chipset DriversChipset Installation Utility Ver. 9.1.1.1020
Intel Storage DriversMatrix Storage Drivers Ver. 8.8.0.1009
Intel Graphics DriversVersion 15.16
3D-Games Benchmarks and Settings
BenchmarkDetails
Far Cry 2Version: 1.0.1
Far Cry 2 Benchmark Tool
Video Mode: 1280x800
Direct3D 9
Overall Quality: Medium
Bloom activated
HDR off
Demo: Ranch Small
GTA IVVersion: 1.0.3
Video Mode: 1280x1024
- 1280x1024
- Aspect Ratio: Auto
- All options: Medium
- View Distance: 30
- Detail Distance: 100
- Vehicle Density: 100
- Shadow Density: 16
- Definition: On
- Vsync: Off
Ingame Benchmark
Left 4 DeadVersion: 1.0.0.5
Video Mode: 1280x800
Game Settings
- Anti Aliasing none
- Filtering Trilinear
- Wait for vertical sync disabled
- Shader Detail Medium
- Effect Detail Medium
- Model/Texture Detail Medium
Demo: THG Demo 1
Audio Benchmarks and Settings
BenchmarkDetails
iTunesVersion: 8.1.0.52
Audio CD ("Terminator II" SE), 53 min.
Convert to AAC audio format
Lame MP3Version 3.98
Audio CD "Terminator II SE", 53 min
convert WAV to MP3 audio format
Command: -b 160 --nores (160 Kbps)
Video Benchmarks and Settings
BenchmarkDetails
TMPEG 4.6Version: 4.6.3.268
Video: Terminator 2 SE DVD (720x576, 16:9) 5 Minutes
Audio: Dolby Digital, 48000 Hz, 6-channel, English
Advanced Acoustic Engine MP3 Encoder (160 Kbps, 44.1 KHz)
DivX 6.8.5Version: 6.8.5
== Main Menu ==
default
== Codec Menu ==
Encoding mode: Insane Quality
Enhanced multithreading
Enabled using SSE4
Quarter-pixel search
== Video Menu ==
Quantization: MPEG-2
XviD 1.2.1Version: 1.2.1
Other Options / Encoder Menu -
Display encoding status = off
Mainconcept Reference 1.6.1Version: 1.6.1
MPEG-2 to MPEG-2 (H.264)
MainConcept H.264/AVC Codec
28 sec. HDTV 1920x1080 (MPEG-2)
Audio:
MPEG2 (44.1 kHz, 2-channel, 16-bit, 224 Kbps)
Codec: H.264
Mode: PAL (25 FPS)
Profile: Settings for eight threads
Adobe Premiere Pro CS4Version: 4.0
WMV 1920x1080 (39 sec.)
Export: Adobe Media Encoder
== Video ==
H.264 Blu-ray
1440x1080i 25 High Quality
Encoding Passes: one
Bitrate Mode: VBR
Frame: 1440x1080
Frame Rate: 25
== Audio ==
PCM Audio, 48 kHz, Stereo
Encoding Passes: one
Application Benchmarks and Settings
BenchmarkDetails
Grisoft AVG Anti-Virus 8Version: 8.5.287
Virus base: 270.12.16/2094
Benchmark
Scan: some compressed ZIP and RAR archives
Winrar 3.9Version 3.90 x64 BETA 1
Compression = Best
Benchmark: THG-Workload
Winzip 12Version 12.0 (8252)
WinZIP Commandline Version 3
Compression = Best
Dictionary = 4096KB
Benchmark: THG-Workload
Autodesk 3d Studio Max 2009Version: 9 x64
Rendering Dragon Image
Resolution: 1920 x 1280 (frame 1-5)
Adobe Photoshop CS 4 (64-Bit)Version: 11
Filtering a 16MB TIF (15000x7266)
Filters:
Radial Blur (Amount: 10; Method: zoom; Quality: good)
Shape Blur (Radius: 46 px; custom shape: Trademark sysmbol)
Median (Radius: 1px)
Polar Coordinates (Rectangular to Polar)
Adobe Acrobat 9 ProfessionalVersion: 9.0.0 (Extended)
== Printing Preferenced Menu ==
Default Settings: Standard
== Adobe PDF Security - Edit Menu ==
Encrypt all documents (128-bit RC4)
Open Password: 123
Permissions Password: 321
Microsoft Powerpoint 2007Version: 2007 SP2
PPT to PDF
Powerpoint Document (115 Pages)
Adobe PDF-Printer
Deep Fritz 11Version: 11
Fritz Chess Benchmark Version 4.2
Synthetic Benchmarks and Settings
BenchmarkDetails
3DMark VantageVersion: 1.02
Options: Performance
Graphics Test 1
Graphics Test 2
CPU Test 1
CPU Test 2
PCMark VantageVersion: 1.00
PCMark Benchmark
Memories Benchmark
SiSoftware Sandra 2009Version: 2009 SP3
Processor Arithmetic, Cryptography, Memory Bandwith
9. Benchmark Results: Synthetics

Sandra shows signficantly improved computing power for the Core i5-661 at 3.33 GHz, but this doesn’t necessarily reflect real-world applications. However, have a look at the encryption benchmark results, which are much accelerated on the new Clarkdale CPU.

This is one of the most amazing results. Thanks to Intel’s six additional instructions accelerating AES encryption and decryption, the performance boost is almost 12x when compared to the Core 2 Duo E8600. Keep in mind that we did not have to modify or update the benchmark to get these results.

The encryption score is similarly high, although SHA is not supported.

The increased memory bandwidth is most likely a result of the on-package memory controller (which, in turn, isn't as effective as Lynnfield's on-die memory controller).

PCMark Vantage also shows decent performance gains for the Core i5 versus the Core 2 Duo processor at the same nominal clock speed. Keep in mind that Core i5 takes advantage of its Turbo Boost feature, which lifts the CPU to a maximum of 3.60 GHz.

10. Benchmark Results: Games And 3DMark Vantage

Far Cry still runs better on an AMD system, thanks to the 785G chipset.

In Left 4 Dead, Intel’s new Core i5-661 can actually overtake AMD with a bang.

3DMark’s score says it all. The new CPU/GPU combo is much faster than Core 2 Duo and G45. Bear in mind that these are scores taken from the app's Entry suite, whereas yesterday's launch coverage employed the Performance preset. The point remains the same: you can do some very entry-level gaming with HD Graphics, but anything beyond medium/low settings and dismally-archaic resolutions will be beyond what integrated graphics can handle.

11. Benchmark Results: Applications

3ds Max runs faster on the new Core i5 dual-core, but part of the performance benefit can be found in the fact that Turbo Mode accelerates the clock speeds up to 3.6 GHz under heavy load. This being a threaded test, we wouldn't expect to see the full benefit of Turbo; however, a single bin should still be available when we're until the CPU's TDP limit.

We’re seeing significant advantages when scanning for viruses using AVG anti-virus. Other AV solutions might show different results, though.

Creating a PDF document out of Powerpoint still is faster on Intel systems than on our AMD test rigs, but in this test the Core i5-661 has no noticeable advantage compared to Core 2 Duo. The Core 2’s larger L2 cache could be an advantage in this test.

Photoshop benefits signficantly from the new Core i5 dual-core. Although the processing time of our workload decreases by a quarter, part of this is due to the increased i5 clock speed with Turbo Boost. Hyper-Threading also likely comes into play, since our filters are all threaded.

WinRAR’s performance gains are probably due to the inclusion of Hyper-Threading, which maximizes utilization in threaded applications, such as WinRAR.

We see more performance in WinZip, but this time it's likely a result of Turbo Boost, since this app is not optimized for multiple cores.

12. Benchmark Results: Audio/Video

We didn’t find many performance benefits when converting digital audio into Apple’s format. We’ve been using this rather old version for the sake of comparable results. You see the processor benchmarks in our CPU charts soon.

Lame seems to be faster mainly because of Turbo Boost.

MainConcept shows significant performance gains, while DivX and Xvid transcoding scale rather linearly.

13. Power Consumption

We didn’t use a high-efficiency power supply, nor did we bother to optimize anything. Yet, the DH55TC/Core i5-661 system delivered very impressive results. Idle power at 30W was as low as we could go with a Core 2 Duo E7200, a G31 motherboard, and a high efficiency power supply around one year ago. Now, we’re hitting this low idle power level just with regular components. A high-efficiency power supply, energy-efficient hard drive, and some voltage modding could easily bring a similar system to roughly 25W idle power. The amazing part is that it would still beat any Core 2 Duo system.

The two AMD systems require significantly more power at idle. This is where the low-power Athlon II X2 240e shines compared to the regular Phenom II X2.

The difference at peak power is not as large as at idle. Still, given that the new Core i5 dual-core system delivers significantly better performance, the drop from 92W to 83W represents a roughly 10% reduction.

The Athlon II X2 240e’s 45W TDP is a huge advantage here, greatly narrowing power consumption gap against the Core 2 Duo machine. However, the Phenom II X2 still requires much more power. The difference is at least as large as the Core i5 661’s idle power requirement.

14. Efficiency Results

Our efficiency run consists of several applications written into a batch script in the following order:

  • 3ds Max
  • DivX
  • Xvid
  • Lame
  • MainConcept
  • PDF Creation
  • Photoshop
  • AVG Anti Virus
  • WinRAR
  • WinZip


Some of these applications don’t take advantage of multiple processing cores; others do heavily. The batch file creates time stamps at the beginning of the run and once it has finished. This way we track the total time required for the test run to complete.

In the meantime, we also track power consumption in one-second intervals during the test run. This allows us to examine power consumption for each application and to create power consumption profiles for each system. The result is runtime performance score and power consumption readings, which we use to analyze efficiency. Idle power is taken out of the equation since differences are rather small.

The runtime reflects total performance of the test system and reveals benefits for the Core i5-661 in the same range as we’ve seen in individual benchmark runs.

The average power used during our efficiency workload was lowest on the new Core i5…

…as well as the total power used to complete the workloads. This is where the new Intel platform strikes hardest. If we now go ahead and relate performance to watt-hours used…

… we get a score that says that Intel’s new Core i5-661 delivers 43% more performance per watt than a Core 2 Duo machine with the G45 chipset and twice the efficiency as an Athlon II X2 240e on AMD’s 785G. Clearly, more performance combined with reduced power consumption results in a pretty heavy efficiency dominance.

Our workload does not include any idle time, which some might criticize. However, in this case, the extremely low idle power of the Core i5-661 system would move the results even more in its favor, as it requires significantly less power.

15. Conclusion

This article looked at the power consumption and efficiency of Intel’s new mainstream dual-core processors, the Core i3 and Core i5 for LGA 1156. All of them now integrate a new graphics unit called HD Graphics, regardless of whether you want it or use it. The graphics core delivers decent performance, but it certainly can’t beat any discrete graphics solution above the ultra-low budget level. The new processors are extremely strong when it comes to encrypting or decrypting AES (we’ll have another article dealing with this), but they also outperform both Core 2 Duo and today’s dual-core AMD offerings in every benchmark.

Processor and system power consumption have decreased significantly. Low power requirements that were only within range for high-efficiency, low-performance solutions can now be reached with mainstream components. Last but not least, Intel has again implemented Turbo Boost, which accelerates one or both cores to up to 3.73 GHz under peak load conditions (3.6 GHz in the case of our Core i5-661) as long as the speed boost fits into the processor’s thermal power envelope. The only weaknesses we found were that this principle doesn’t apply to graphics (save for mobile Core i5 solutions) and Intel’s pricing remains well above AMD’s offerings.

It almost seems like nothing can rain on Intel’s parade. The introduction of the Nehalem architecture with Core i7 on LGA 1366 secured the high-end for Intel. Core 2 Duo has been expensive but dominant in the mainstream, and the recently-introduced LGA 1156 platform will be taking care of today’s and future systems in between the budget and upper-mainstream. Intel’s new Core i5 and i3 processors must be a nightmare for AMD, which continues to lose ground in the mainstream. Intel dominates performance, and it clearly rules power efficiency now. The only factor left in AMD’s hand is price and effective value, but this won’t last forever without some major changes.

If anyone has good suggestions for AMD, now would be the time to make them. What do you think of efficiency? Where do you think AMD should improve to get back into the game?