Painfully Backwards Compatible

AMD’s big selling point of its Socket-AM3 processors is that they can still be used in Socket-AM2+ motherboards. In other words, you can use them in DDR3 or DDR2 motherboards. There’s a catch - the Phenom II X4 955 needs a BIOS update to work properly. And guess what? Not all motherboards have that BIOS support yet.

It’s not a major change but the fact of the matter is that AMD and its board partners have not done the work necessary to enable support across the board at launch. That means that if you have a Socket-AM2+ board, you may not be able to run the Phenom II X4 955 just yet.


Socket-AM2+

I ran into this problem with my AM2+ testbed. For the past couple of AMD reviews I’ve used MSI’s DKA790GX Platinum, a 790GX based motherboard. AMD actually sent me the board with my first Phenom II X4 940. Unfortunately it doesn’t have an updated BIOS, so the 955 only runs at 800MHz and won’t POST at 3.2GHz. Great.

The following AM2+ boards currently have support for the 955:

Motherboard Socket Chipset BIOS Version
ASUS M3A79-T Deluxe AM2+ AMD 790FX 20090330 0803
DFI Lanparty DK 790FXB-M2RSH AM2+ AMD 790FX 200900327*
ASUS M3A 78-T AM2+ AMD 790GX 20090401 0903
Gigabyte MA790GP-DS4H AM2+ AMD 790GX 20090407 F4*
*These boards still have some known issues with the Phenom II X4 955

 

And more are coming. AMD suggests that you look at its Motherboard Compatibility page before you pull the trigger if you’re looking to put one of these chips into an older board.


Socket-AM3

Even Socket-AM3 boards will need a BIOS update but those seem a bit more ready to go. Unfortunately because of all of this board switching, some of my 955 numbers aren’t exactly comparable to my older 940 numbers. I’m using different motherboards (Socket-AM3 vs. AM2+) and different memory (DDR3-1333 vs. DDR2-1066). The numbers are close enough, but there were a couple of situations where performance scaled more than it should have or went negative.

Overall it’s not a huge deal but it’s frustrating for anyone looking to save money and upgrade to the 955 but using an older motherboard.

Index The Move to DDR3: You Can Do It
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  • dragonsphere - Tuesday, July 28, 2009 - link

    I read articles like this all the time for multiple websites. I am a professional application performance tester and I can tell you that most of these articles are junk just to stir up the masses. Most of their statistics are based on averages. This means that 51% of the time they are wrong. Have you noticed that none of them show confidence tests to prove that their data is accurate? Also they don't use 90th percentiles. I think this is due to the lack of the tools that they are using to generate these sub-standard statistics. Until the software they are using is more precise I would consider these tests to be junk science. Reply
  • cal954 - Saturday, May 02, 2009 - link

    Thanks for all the information. I used this model to build my first computer, although no matter what I try to do, my CPU-Z never shows me the multiplier being anything but 4.0 and I can't get my core speed above 800 even w/ CnQ disabled. Reply
  • Hamlet2000 - Saturday, May 09, 2009 - link

    You need to update your bios on your motherboard. I had the exact same thing with my new Phenom II 955 build on a Gigabyte board. Once you update, go into your bios and set the clock at 200 x 16. You'll notice the speed difference right away - it's a smoking fast CPU! Reply
  • Edgemeal - Monday, April 27, 2009 - link

    Geez, some of you people make it sound like AMD has to have the fastest CPU in the market or they just aren't any good or something!

    AMD knows what their chip/PC parts are worth in the market place and their price/performance fits in very nicely. I applaud AMD, without them you'd be reading about the new $900 2GHz P4s right about now LOL!
    Reply
  • swapnadip - Friday, April 24, 2009 - link

    Either AnandTech is Intel fan or Intel pays them hefty Loyalty.

    If not, then why every other reviewieng site shows AMD PHENOM 2 X4 955 BE defeating Core i7 940 on evey computing prospects.

    On some instances it has bashed on Core i7 965 extreme.

    This is pretty much biased and helping INTEL play their MONOPOLOY in this sector. In today's market, no two rivals can have their top of line product bearing differences of Day and Night like shown in this review.

    Thanks
    Reply
  • swapnadip - Friday, April 24, 2009 - link

    Either AnandTech is Intel fan or Intel pays them hefty Loyalty.

    If not, then why every other reviewieng site shows AMD PHENOM 2 X4 955 BE defeating Core i7 940 on evey computing prospects.

    On some instances it has bashed on Core i7 965 extreme.

    This is pretty much biased and helping INTEL play their MONOPOLOY in this sector. In today's market, no two rivals can have their top of line product bearing differences of Day and Night like shown in this review.

    Thanks
    Reply
  • swapnadip - Friday, April 24, 2009 - link

    Either AnandTech is Intel fan or Intel pays them hefty Loyalty.

    If not, then why every other reviewieng site shows AMD PHENOM 2 X4 955 BE defeating Core i7 940 on evey computing prospects.

    On some instances it has bashed on Core i7 965 extreme.

    This is pretty much biased and helping INTEL play their MONOPOLOY in this sector. In today's market, no two rivals can have their top of line product bearing differences of Day and Night like shown in this review.

    Thanks
    Reply
  • iFX - Friday, April 24, 2009 - link

    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+
    PII 940 BE = $189.99 on Newegg right now and for the last week+

    ----

    Why is it every AMD article on this site has errors?
    Reply
  • wowo - Friday, April 24, 2009 - link

    how x264?x264 benchmark 2.0 is very old .

    it is 819,but new x264 is 1139.intel is better for 1139 a lot.

    please test wirh new x264.
    Reply
  • ultrageek1111 - Friday, April 24, 2009 - link

    you know what they say about black processors... Reply

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