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Voltage Table And Test Setup

Clarkdale Efficiency: The Perfect Clock Rate For Intel's Core i5-661

We tested using Intel’s reference LGA 1156 cooler, which comes bundled with all Core i5 dual-core boxed processors and can handle a Core i5 at up to about 4 GHz. It has a copper core and is quiet enough for an average desktop PC. But since it's half as high as the quad-core coolers designed to tackle 95W or 130W TDPs, you shouldn't expect too much from it. We decided to use it since not everyone would want to spend another $30 to $80 for a premium cooler. We recommend getting a tray CPU and purchasing a CPU cooler separately if you want less noise and/or better cooling.

System Hardware
Performance Benchmarks
Motherboard (Socket LGA1156)MSI H55M-ED55 (Rev. 1.0)
Chipset: Intel H55, BIOS: 1.1 Beta 1 (09/08/2009)
CPU IntelIntel Core i5-661 (32nm, 3.33 GHz, 2 x 256KB L2 and 4MB L3 Cache, TDP 87W, Rev. B1)
RAM DDR3 (dual)2 x 2GB DDR3-1600 (Corsair CM3X2G1600C9DHX)
GraphicsIntel HD Graphics
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
Intel Chipset DriversChipset Installation Utility Ver.
Intel Storage DriversMatrix Storage Drivers Ver.

Benchmarks and Settings

Audio Benchmarks and Settings
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
TMPEG 4.6Version:
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 ==
== 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)
MPEG-2 (44.1 kHz, 2-channel, 16-bit, 224 Kbps)
Codec: H.264
Mode: PAL (25 FPS)
Profile: Settings for eight threads
Application Benchmarks and Settings
Grisoft AVG Anti-Virus 8Version: 8.5.287
Virus base: 270.12.16/2094
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)
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
Powerpoint Document (115 Pages)
Adobe PDF-Printer
Deep Fritz 11Version: 11
Fritz Chess Benchmark Version 4.2
Display all 17 comments.
This thread is closed for comments
  • 0 Hide
    JohnnyLucky , February 17, 2010 5:12 AM
    Thanks for an informative overclocking article that helps put things in perspective.
  • 0 Hide
    shubham1401 , February 17, 2010 6:15 AM
    Nice article!!

    These i5 are good overclock-able chips :) 
  • 0 Hide
    racermx187 , February 17, 2010 6:30 AM
    Very nice article and I totally agree with the conclusion paragraph and changing the way CPUs are looked at for use.
  • 0 Hide
    anamaniac , February 17, 2010 7:43 AM

    But after all that, I'm just wondering what kind of efficiency I could get out of a high binned dual core that's left on stock clocks but heavily undervolted with 2x2GB 1.5v DDR3, a 80GB x18-m and a 5670 and a board/PSU designed for low powert usage. Hell, my current CPU would use as much power as that entire system. =)
    But, we didn't buy i7's for the performance-to-watt ratio now, did we?
  • 0 Hide
    JeanLuc , February 17, 2010 8:06 AM
    Patrick Schmid and Achim Roos - Can I ask why are your articles are always co-authored?

    Thank you.
  • 1 Hide
    coldmast , February 17, 2010 1:51 PM
    JeanLucPatrick Schmid and Achim Roos - Can I ask why are your articles are always co-authored? Thank you.

    The co-authoring probably has to do with one being the writer of the original article and the other being the translator, or one is the SME and the other is the technical writer.
  • 0 Hide
    envolva , February 17, 2010 3:07 PM
    We could use a i5 750 at stock speed to see how it compare with an overclocked i5 661. Maybe throw an i3 in there too to keep things in perspective.

    It would be nice to see Turbo Boost disabled (power savings still up) and see how the overal efficiency behaves. Whitout Turbo Boost, you can keep the multiplier under control maybe reducing the core voltage needed.
  • 0 Hide
    burnley14 , February 17, 2010 4:24 PM
    Pretty interesting that there was not much of an efficiency increase even with small overclocks. Maybe this is because of Turbo Boost? If so, I think envolva's got the right idea.
  • 0 Hide
    Anonymous , February 17, 2010 5:54 PM
    My question is what role the 45 nano graphics core plays in this?

    Might have been more interesting to use a i5-670 part, where the base core speed is 133 mhz higher and graphics core starts at 733 mhz versus 900.

    The power/clock speed graph looks a little odd, I wonder how much of it is the cpu core staying low power while the graphics core uses more and more energy?
  • -1 Hide
    ta152h , February 17, 2010 8:10 PM
    I'd be curious if overclocking the graphics part increases pure processor performance at all. The knee-jerk reaction is that this is an idiotic question, but consider the memory controller is in the video controller, and there's a possibility that even if you don't use the IGP, you might be well to overclock it to improve the memory performance slightly.
  • -1 Hide
    sandypants , February 17, 2010 8:41 PM
    What were the temperatures like?
  • -1 Hide
    Anonymous , February 18, 2010 9:27 AM
    I must say that in my mind your testing is faulty from the start: if you just start increasing base clock with stock voltages, the outcome is obvious even without testing (that best efficiency is around the point you can go without rising voltages). If you want to get us some real and even remotely useful data on microarchitecture/manufacturing process efficiency you must UNDERVOLT every test frequency you use down to minimum stable voltage! So any chance we will see that in future?
  • -2 Hide
    fernandogmd , February 18, 2010 2:38 PM
    It would´ve been interesting to see some game benchmarks as well. To see if there´s any benefit to efficiently overclock the cpu for games.
  • 0 Hide
    teknic111 , February 18, 2010 5:48 PM
    I want Gulftown!!!
  • 0 Hide
    Catalina588 , February 19, 2010 12:44 AM
    Is it just me, or did I miss the Voltage Table on the Voltage Table and Settings page? What voltages were used at each BCLK?
  • 0 Hide
    Anonymous , February 20, 2010 9:27 PM
    It's not just you.
  • 0 Hide
    tiktianc , February 22, 2010 2:59 AM
    i think there should be a effeciency article done for an i3, i mean they're really easy to overclock with the one in my mITX system doing 3.8GHz easy on stock cooler