1. Welcome to TechPowerUp Forums, Guest! Please check out our forum guidelines for info related to our community.

Phenom II X4 800 Series Can Address Full 6 MB L3 Cache

Discussion in 'News' started by btarunr, Mar 9, 2009.

  1. btarunr

    btarunr Editor & Senior Moderator Staff Member

    Joined:
    Oct 9, 2007
    Messages:
    31,312 (10.27/day)
    Thanks Received:
    15,519
    Location:
    Hyderabad, India
    While AMD played smart in diverting all its engineering resources in designing only one core: the Deneb / Shanghai, and then carving out umpteen SKUs out of them based on disabling cores, and/or setting L3 cache amounts, its implementation seems to be shoddy, to the least. Weeks ago, a Korean enthusiast found an easy way to unlock the factory-disabled fourth core on some Phenom II X3 (Heka) processors. A fresh report suggests that it is possible to enable the complete L3 cache on the Phenom II X4 800 series processors.

    The series is AMD's line of Deneb-based 45 nm quad-core processors with 2 MB of L3 cache disabled, leaving 4 MB that can be addressed by the processor. An enthusiast found the Phenom II X4 810 processor to be spontaneously able to address 6 MB of L3 cache, when used on an ASRock AOD790GX /128M motherboard. The most likely cause of this could be "poorly-coded" motherboard BIOS that is able to see the Deneb core "as is". The motherboard was using BIOS version 1.40, that adds Phenom II support. The additional cache was found to have a positive impact on system performance. Beyond that, the enthusiast did not provide an explanation. After clearing the CMOS of the motherboard, it was able to correctly detect the processor with its intended specifications.

    [​IMG] [​IMG]

    Source: XTReview
     
  2. btarunr

    btarunr Editor & Senior Moderator Staff Member

    Joined:
    Oct 9, 2007
    Messages:
    31,312 (10.27/day)
    Thanks Received:
    15,519
    Location:
    Hyderabad, India
    Many Thanks to cdawall for sending this in.
     
  3. Imsochobo New Member

    Joined:
    Feb 19, 2009
    Messages:
    514 (0.20/day)
    Thanks Received:
    35
    Location:
    I live in Norway, in the province Buskerud.
    seems like you can do alot with theese PHII's.

    Its just like the X800 pro VIVO -> XT and all the other gfx's that required minor mods.
     
  4. ShadowFold

    ShadowFold New Member

    Joined:
    Dec 23, 2007
    Messages:
    16,921 (5.69/day)
    Thanks Received:
    1,642
    Location:
    Omaha, NE
    When I saw this on the frontpage I facepalmed
    Damn AMD, doing anything for sales eh lol
     
  5. r9

    r9

    Joined:
    Jul 28, 2008
    Messages:
    2,144 (0.78/day)
    Thanks Received:
    284
    Getting free performance is fun.
    And yet again unlocking is done on crappy brand board :D.
     
  6. PVTCaboose1337

    PVTCaboose1337 Graphical Hacker

    Joined:
    Feb 1, 2006
    Messages:
    9,512 (2.60/day)
    Thanks Received:
    1,143
    Location:
    Dallas, Texas
    Free performance = win. Amd gets more sales, we get more speed.
     
    10 Year Member at TPU
  7. BazookaJoe

    BazookaJoe

    Joined:
    Sep 4, 2008
    Messages:
    874 (0.32/day)
    Thanks Received:
    240
    It was my understanding that the X3 chips where chips that had failed X4 quality control on 1 core - and rather than throw them away they are sold as X3's

    This would mean that enabling core no. 4 would be enabling a core that had already been branded reject by the factory.

    Is this wise? - I'd rather just buy a 4 core CPU - that has PASSED quality control - is there REALLY such a price difference?
     
  8. soryuuha New Member

    Joined:
    Jun 27, 2008
    Messages:
    95 (0.03/day)
    Thanks Received:
    6
    $72 usd?
     
  9. BazookaJoe

    BazookaJoe

    Joined:
    Sep 4, 2008
    Messages:
    874 (0.32/day)
    Thanks Received:
    240
    OK, I admit that's worse than I thought it would be. :\

    But personally, I'd still rather pay the extra and not have to worry about stability - At the end of the day you are still unlocking a reject core.

    I suppose its really down to where between cost & stability your requirements lie.
     
  10. Kei

    Kei

    Joined:
    Mar 3, 2008
    Messages:
    2,122 (0.73/day)
    Thanks Received:
    618
    I imagine the people that are looking at this most are people who are looking for benchmark runs not people looking for outright stability. Same for the 810 L3 cache thing, it's a cool trick but we all know they disabled it for a reason other than just to make X3's and 4Mb L3 cache levels.

    Also, once the bios's for these boards get updated this problem will go away away as these chips are all still on their first bios releases so they're far from optimized just yet. I'm sure a lot of people out there soiled their pants when they found these things though haha.

    I however wouldn't try to do either of these on a daily basis because of the risk for instability that is bound to happen at some point.

    Kei
     
  11. newtekie1

    newtekie1 Semi-Retired Folder

    Joined:
    Nov 22, 2005
    Messages:
    22,180 (5.94/day)
    Thanks Received:
    8,086
    Just because it is disabled, that doesn't mean it is unstable. Some might be perfectly good, but were still disabled just to fill the demand of lower end markets.
     
    Nick89 and WarEagleAU say thanks.
    10 Year Member at TPU Crunching for Team TPU More than 25k PPD
  12. WarEagleAU

    WarEagleAU Bird of Prey

    Joined:
    Jul 9, 2006
    Messages:
    10,811 (3.09/day)
    Thanks Received:
    547
    Location:
    Gurley, AL
    Seems like a nice little hidden gem to me. too bad they are gonna correct this minor tweak. Id like to get me an 800 series with 6mb of cache just to see how well it performs compared to the 4mb. Crappy Asrock board, someone try it on the MSI DK790GX uber board.
     
  13. spearman914

    spearman914 New Member

    Joined:
    Apr 14, 2008
    Messages:
    3,339 (1.17/day)
    Thanks Received:
    502
    Location:
    Brooklyn, New York 11223
    Wish we can do this with Intel's. :D
     
  14. showstopper41 New Member

    Joined:
    Jan 15, 2009
    Messages:
    12 (0.00/day)
    Thanks Received:
    0
    AMD's all new Phenom II's are tricky. If it is possible at all 790GX mainboards, that is a new option against risky phenom II x3 720's 4th core.
     
  15. eidairaman1

    eidairaman1

    Joined:
    Jul 2, 2007
    Messages:
    14,399 (4.58/day)
    Thanks Received:
    2,133
    i wouldnt be surprised if Modders start taking the later bios code and unlocking it so it detects the processors differently.
     
  16. Hayder_Master

    Hayder_Master

    Joined:
    Apr 21, 2008
    Messages:
    5,205 (1.83/day)
    Thanks Received:
    663
    Location:
    IRAQ-Baghdad
    nice when you got something free
     

Currently Active Users Viewing This Thread: 1 (0 members and 1 guest)