Intel Core i7-875K And Core i5-655K Battle Beyond 4 GHz

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Do you like the idea of an unlocked clock multiplier, but don't want to pay $1,000 for an Extreme Edition? Intel's K-series CPUs bring overclocking down to the mainstream. The question is: can these scalable parts keep up with AMD's Black Edition CPUs?

Test Setup And Benchmarks

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Test Hardware
ProcessorsIntel Core i7-875K (Lynnfield) 2.93 GHz, LGA 1156, 8 MB L3, Hyper-Threading enabled, Power-savings enabled
Row 1 - Cell 0 Intel Core i5-655K (Clarkdale) 3.2 GHz, LGA 1156, 4 MB L3, Hyper-Threading enabled, Power-savings enabled
Row 2 - Cell 0 AMD Phenom II X6 1090T (Thuban) 3.2 GHz, Socket AM3, 4 GT/s HyperTransport, 6 MB L3, Power-savings enabled enabled
Row 3 - Cell 0 AMD Phenom II X4 965 BE (Deneb) 3.4 GHz, Socket AM3, 4 GT/s HyperTransport, 6 MB L3, Power-savings enabled
MotherboardsASRock 890FX Deluxe3 (Socket AM3) 890FX/SB850, BIOS 1.40
Row 5 - Cell 0 Asus Maximus III Formula (LGA 1156) P55 Express, BIOS 1706
MemoryCrucial 8 GB (4 x 2GB) DDR3-1066 7-7-7-20 @ DDR3-1333
Hard DriveIntel SSDSA2M160G2GC 160GB SATA 3 Gb/s
Row 8 - Cell 0 Intel SSDSA2MH080G1GN 80GB SATA 3 Gb/s
GraphicsAMD Radeon HD 5970 2 GB
Power SupplyCooler Master UCP 1100W
HeatsinkNoctua NH-D14 w/ LGA 1156 and Socket AM3 Brackets
System Software And Drivers
Operating SystemWindows 7 Ultimate 64-bit
DirectXDirectX 11
Platform DriverIntel INF Chipset Update Utility 9.1.1.1015
Graphics DriverCatalyst 10.4
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Benchmarks and Settings
Audio Encoding
iTunesVersion: 9.1.1.12 (64-bit), Audio CD ("Terminator II" SE), 53 min., Default format AAC
Video Encoding
TMPGEnc 4.7Version: 4.7.3.292, Import File: "Terminator II" SE DVD (5 Minutes), Resolution: 720x576 (PAL) 16:9
DivX 6.9.2Encoding mode: Insane Quality, Enhanced Multi-Threading, Enabled using SSE4, Quarter-pixel search
Xvid 1.2.2Display encoding status=off
MainConcept Reference 2.0MPEG2 to MPEG2 (H.264), MainConcept H.264/AVC Codec, 28 sec HDTV 1920x1080 (MPEG2), Audio: MPEG2 (44.1 KHz, 2 Channel, 16-Bit, 224 Kb/s), Mode: PAL (25 FPS), Profile: Tom’s Hardware Settings for Qct-Core
HandBrake 0.9.4Version 0.9.4, convert first .vob file from The Last Samurai to .mp4, High Profile
Applications
Autodesk 3ds Max 2010 (64-bit)Version: 2010 Service Pack 1, Render Space Flyby Scene at 1920x1080 (HDTV)
WinRAR 3.90Version 3.90 (64-bit), Benchmark: THG-Workload (334 MB)
7-ZipVersion 4.65, Built-in Benchmark
Adobe Photoshop CS4Radial Blur, Shape Blur, Median, Polar Coordinates filters
Synthetic Benchmarks and Settings
3DMark VantageVersion: 1.02, GPU and CPU scores
PCMark VantageVersion: 1.00, System, Memories, TV and Movies, and Productivity benchmarks, Windows Media Player 10.00.00.3646
SiSoftware Sandra 2010CPU Test=CPU Arithmetic/Multimedia, Memory Test=Bandwidth Benchmark, Cryptography
Games
CrysisHigh Quality Settings, No AA / No AF, 4xAA / No AF, vsync off, 1680x1050 / 1900x1200 / 2560x1600, DirectX 10, Patch 1.2.1, 64-bit executable
Just Cause 2High Quality Settings, No AA / 16xAF, 4xAA / 16xAF, vsync off, 1680x1050 / 1920x1200 / 2560x1600, Desert Sunrise Benchmark, Steam Version
Call of Duty: Modern Warfare 2Ultra High Settings, No AA / No AF, 4xAA / No AF, 1680x1050 / 1920x1200 / 2560x1600, Second Sun, 450 second sequence, Fraps
DiRT 2High / Ultra High Settings, No AA / No AF, 8xAA / No AF, 1680x1050 / 1920x1200 / 2560x1600, In-Game Benchmark, Steam Version
Chris Angelini
Chris Angelini
Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.
113 Comments Comment from the forums
  • xurwin
    BE vs K!! go K series
    Reply
  • sarsoft
    LGA 1366 i7 hopefully will be available soon. GRRRRRRRRR........
    Reply
  • Known2Bone
    wow now that is some serious over-clocking... and here i am trying to push my 955 up past 3.93. i would have liked to see some liquid cooling tossed in to spice things up and maybe one more 5970... great job Chris!
    Reply
  • cangelini
    Known--I'll talk to Thomas about getting some of that going in his next System Builder Marathon piece. He loves liquid cooling =)
    Reply
  • hok
    still love my 930...
    Reply
  • Stardude82
    Intel did release the E6500K for the LGA 775, but only in Asia.

    The only good thing here is that these chips will probably ship with heat sinks that don't suck and a good price drop for the i7 870. Otherwise, who cares, FSB stability on decent P55 boards has not been a problem. What the socket really needs from Intel is a better chip-set, not easier overclockers.
    Reply
  • nurgletheunclean
    9. All prize winners are responsible for taxes and other surcharges on the prizes they win.

    1099'd for $1499? I hate how contest prizes all have full MSRP on everything. Even if you win it end up costing you $500+ in taxes.
    Reply
  • SpadeM
    Intel makes good cpus, that's a given. Their problem lies in the pricing of such chips. I mean if you could buy a processor because you want to overclock it then the locked but cheaper one is as good as the unlocked one. Sure, it's more difficult, but I for one love a challenge.

    Also, as a side note, I do have a problem with the benchmarks and more accurately with the conclusion you extracted from them. Who in their right mind would buy a processor, overclock it, and then do iTunes all day ... I mean come on, there's more to life then music ripping. What I'm saying is that the benchmark section SHOULD be remade entirely. Same old tests, that I could anticipate the outcome of every time, isn't a very compelling way to make a point. I do appreciate the game section though, at least i saw a new title.
    Reply
  • jecastej
    Finally, very good news for serious desktop processing power that wont leave me with an empty wallet. The 875K is going to be my next CPU for 3D modeling and rendering. I hope it will keep me entertained for a while =)

    Don't get me wrong but I was getting bored with the tiny world of ARM and Tegra and on the other side of the spectrum the hexacores and dual Xeons were far and away for my budget.
    Reply
  • anamaniac
    sarsoftLGA 1366 i7 hopefully will be available soon. GRRRRRRRRR........On Xtremesystems.org, I just read about a guy reaching 4.644GHz on air with his i7 930. Granted, he has a great chip, but by no means is a unlocked multiplier needed for high overclocks.

    If I were to build a new PC, the 1090T/1055T would be very complelling.
    Reply