Die size hasn’t changed, clock speeds barely went up, and performance per clock also remained static. But what’s this?

Ah yes, AMD is improving its 45nm manufacturing process and today we have the latest incarnation of AMD’s 45nm silicon.

The first versions of AMD’s 45nm Phenom II couldn’t really go much higher than the final 65nm Phenom without increasing voltage. By comparison, Intel’s Core i7 920 could go from 2.66GHz all the way up to 3.80GHz without so much as a single extra millivolt in our tests.

This new Phenom II however can also hit 3.80GHz without increasing the core voltage. At least that’s what one of our samples did in our testing. Whether it’s 3.8GHz or 3.6GHz, the fact of the matter is that AMD’s 45nm process is improving and that’s what’s behind todays introduction of the Phenom II X4 955. Architecturally the Phenom II hasn't changed; if you're curious about what makes these things tick, please look at our original article on the CPU.

Clocked at 3.2GHz with a 2.0GHz un-core (or North Bridge) frequency, the 955 isn’t that much different from the 940 in terms of clock speed. The two face off in the table below:

CPU Clock Speed un-core Clock (NB Frequency) Die Size Transistor Count TDP Socket
Phenom II X4 955 3.2GHz 2.0GHz 258 mm2 758M 125W AM3 or AM2+
Phenom II X4 940 3.0GHz 1.8GHz 258 mm2 758M 125W AM2+


This is a Socket-AM3 part, meaning it can work in both DDR2 based Socket-AM2+ motherboards and DDR3 based Socket-AM3 motherboards. There’s a huge compatibility caveat about AM2+ support but I’ll address that shortly. The Phenom II X4 955 is also a Black Edition part, meaning it has an unlocked clock multiplier for easy overclocking.

Along with the 955 there’s also a 945 being introduced today. The 945 is identical to the 940 in core clock speed but has a 2.0GHz un-core and is also AM3 compatible.

Processor Clock Speed un-core Clock L2 Cache L3 Cache TDP Price
AMD Phenom II X4 955 BE 3.2GHz 2.0GHz 2MB 6MB 125W $245
AMD Phenom II X4 945 3.0GHz 2.0GHz 2MB 6MB 125W $225
AMD Phenom II X4 940 BE 3.0GHz 1.8GHz 2MB 6MB 125W $225
AMD Phenom II X4 920 2.8GHz 1.8GHz 2MB 6MB 125W $195
AMD Phenom II X4 910 2.6GHz 2.0GHz 2MB 6MB 95W $???
AMD Phenom II X4 810 2.6GHz 2.0GHz 2MB 4MB 95W $175
AMD Phenom II X4 805 2.5GHz 2.0GHz 2MB 4MB 95W $???
AMD Phenom II X3 720 BE 2.8GHz 2.0GHz 1.5MB 6MB 95W $145
AMD Phenom II X3 710 2.6GHz 2.0GHz 1.5MB 6MB 95W $125
AMD Phenom 9950 2.6GHz 2.0GHz 2MB 2MB 140W $173


The prices are pretty attractive; the 955 will sell for $245 (and it already has been) and the 945 will go for $225. That pits the 955 against Intel’s Core 2 Duo Q9550 ($266) and the Core i7-920 ($284), the latter having a much higher motherboard cost of course.

Processor Price
Intel Core i7-920 (2.66GHz) $284
Intel Core 2 Quad Q9650 (3.00GHz) $316
Intel Core 2 Quad Q9550 (2.83GHz) $266
Intel Core 2 Quad Q9400 (2.66GHz) $213
Intel Core 2 Quad Q8400 (2.66GHz) $183
Intel Core 2 Quad Q8300 (2.50GHz) $183
Intel Core 2 Quad Q8200 (2.33GHz) $163


And you know how I love spoiling surprises so here you have it. Unless you’re running applications that are very well optimized for Intel’s architectures, the Phenom II X4 955 is faster than the Core 2 Quad Q9550. Compared to the Core i7-920, it loses hands down although the chip does come close in some games.

Sorry, I’m not much of a tease :) Now for the rest of the article.

Painfully Backwards Compatible


View All Comments

  • Procurion - Thursday, April 23, 2009 - link

    Cool. My next question would be to wonder why it didn't kick in for the other tests? I guess it wasn't enabled for them? Looks good overall. Reply
  • JarredWalton - Thursday, April 23, 2009 - link

    See page 4 - Turbo mode tends to activate pretty much any time a load is on the CPU. But it's not really "unfair" as all i7 users get that benefit without doing anything extra, plus i7 chips still overclock far beyond that point. Reply
  • ChemicalAffinity - Thursday, April 23, 2009 - link

    Best post ever. Reply
  • whatthehey - Thursday, April 23, 2009 - link

    Congratulations on the cryptic post... or is that pointless post? I'm guessing you're suggesting that the words listed were used with two different companies - AMD and Intel - but if so they certainly weren't used in this article in any way I can see. Care to enlighten the rest of us on the point of your comment?

    Some people are too clever for their own good; others merely think they're clever. Guess which one you are.
  • Lokinhow - Thursday, April 23, 2009 - link

    Oh man, I thinking about the OC
    3.9GHz on Vista x64
    4.2GHz on Vista x86

    Why it happens?
    Does the results are the same using XP x86/x64 and Windows 7 x86/x64?

    That would be interesting to see if it is possible to reach 4.2GHz on Windows 7 x64
  • Griswold - Thursday, April 23, 2009 - link

    Dont hold your breath. Theres more registers (etc) in use under a 64bit OS than a 32bit one. Its highly unlikely that there will be any difference on the exact same hardware. And even if there is a difference between xp/vista/7, 32bit 7 will outdo 64bit 7 as well. 64bit was never the ideal choice for overclocking records...
  • Spoelie - Thursday, April 23, 2009 - link

    In the CS4 test, given the large increase in performance when just going from DDR2 to DDR3, would a faster NB clock (2->2.6/2.8ghz) and faster than DDR1333 memory, while keeping the core at default clock, level the playing field with the core2 processors?

    Seems that in this particular test the phenom is starved for data.
  • duploxxx - Thursday, April 23, 2009 - link

    why do you use these 1GB dimm's in ddr3 config? I would assume you have more oc issues with 4 dimms in stead off 2 dimms?

    G.Skill DDR2-800 2 x 2GB (4-4-4-12)
    G.Skill DDR2-1066 2 x 2GB (5-5-5-15)
    Qimonda DDR3-1066 4 x 1GB (7-7-7-20)
    Corsair DDR3-1333 4 x 1GB (7-7-7-20)
  • Holly - Thursday, April 23, 2009 - link

    Nice article :-)

    btw... last paragraph on the first page... "faster than the Core 2 Duo Q9550." should say "faster than the Core 2 Quad Q9550."
  • ibm386 - Sunday, June 27, 2010 - link

    Intel and Amd are owned by the same person. Since a person can't have monoply in U.S. It has been divided into two different names and obviously diff. CEOs.


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