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Socket AM3: AMD's Phenom II Gets DDR3

Modding And Overclocking–Doable?

Our first thought after hearing that AMD wouldn't be launching a Phenom II X4 940/920 equivalent for the AM3 platform was, "what about all of the enthusiasts who've been eying those high-end models and still want to experiment with DDR3 memory?"

We knew we had a Phenom II X4 940 in the house that didn't scale very well and would likely be replaced soon by another chip that would ideally have more headroom built into it, so we decided to try "creating" a 938-pin AM3 chip out of our 940-pin AM2+ sample. After all, the silicon under its proverbial hood was the same–the only difference was its interface.

So, using a mechanical pencil, we bent the two offending pins back and forth until they snapped off. The chip now fit into our AM3 test platform, albeit not flush due to the metal nubs where each pin broke. Unfortunately, the modded processor would not POST at all, forcing us to conclude that the task wouldn't be as easy as popping off pins. It's truly a shame that enthusiasts can't get access to AMD's AM2 pinout, which would describe the exact role of each pin rather than force us to guess. The most recent tech doc publicly-available relates to the old-school Socket 940 interface.

Wondering if we'd just nuked a perfectly good CPU, we moved the Phenom II X4 940 back to its AM2+ board. Lo and behold, it still ran fine, without any immediately apparent issues.


Thwarted in our efforts to turn AMD's flagship Phenom II into an AM3-compatible part, we switched gears to the Phenom II X3 720 Black Edition. AMD had suggested to us that the Phenom II X3 would theoretically be more receptive to overclocking since it isn't as complex as the quad-core models.

Indeed, using Asus' M4A79T Deluxe, we were able to get the triple-core chip running stably at 150 MHz faster than our X4 940, right around 3.8 GHz.

With a price tag set at $145, this one looks like a no-brainer for enthusiasts who already own a 790-series motherboard and DDR2 memory. Even the Core 2 Duo E8500 we've tested here still costs $190. The Phenom II X3 is going to perform better in apps optimized for more than two cores and it'll hold its own in overclocked comparisons to Intel's Core 2 lineup.

Chris Angelini is an Editor Emeritus at Tom's Hardware US. He edits hardware reviews and covers high-profile CPU and GPU launches.
  • kelfen
    Cheering the underdog in hopes for better compitition to benifit the consumer!
  • groo
    I sure don't see the point of spending cash on DDR3 unless you are also spending cash on i7. I woudn't mind a CPU that can handle DDR3 in the future, but there sure isn't a reason toupgrade to it at today's memory prices.
  • Aatish
    nice review... but....
    strangely AMD is performing better than core i7 920!
    what did I miss? in previous benchmark done by you guys showed AMD performing quite less than what I see in this benchmark! can anyone clear my confusion? please!:)
  • Commlock
    Very good test indeed that shows, IMHO, to go with an overclocked Core i7 if DDR3 is to be preferred. Otherwise, sticking with DDR2 RAM, an AM2+ MoBo and A Phenom II 940-like CPU seems the best optimized system. However, concerns can be put forward on the continuity of the system in couple of years' time, where simply upgrading without major component changes can be discussed.
  • sohei
    an AM2 mobo is compatible with AM3?
  • I understand the fact that you guys compare cpu's in the same price region plus whats available to you and the socket upgrade and all that. But i would really like to see how the AMD 940 Black Edition compare to Intel Corei7 EE 965. And maybe include the corei7 940 to. An all out performance battle with just the benchmark figures that counts
  • waffle911
    The 940 runs at 3 GHz. The 920 and 720 both cruise at 2.8 GHz. But the 910, 810, and 710 all run at 2.6 GHz. There goes the idea that each increment of 10 corresponds to 100 MHz. The 805 chugs along at 2.5 GHz.
    Looks to me like every increment of 10 in the designation yields a 200MHz clock increment, and 5 being 100MHz. But then either the 940 should actually be the 930. Then again, Volvo's recent product nomenclature doesn't add up, either. the V50 is the wagon variant of the S40, and the V70 was the wagon variant of the S60, but is now of the new S80. But they can't change it to V90 because then the Cross-Country variant of the V70 would have to be called he XC90 instead of XC70—but they already have an XC90 SUV. Digging themselves into a hole of consumer confusion, AMD and Volvo both.

    But why is AMD shafting early adopters by shutting out AM2+ PhenomII from the AM3 platform without even offering an AM3 920/940?
  • Well, can't agree with socket chart.
    Let's see (long run)
    AMD&Intel: Socket 7 (intel up to some 266MHz?, AMD up to 550MHz)
    Intel Slot 1 - with FCPGA adapters up to some 1200MHz?
    AMD SlotA - with socketA adapters up to some 1600MHz?
    PPGA s370 ~ 600MHz?
    FCPGA (coppermine) 1100MHz
    FCPGA2 (tualatin) 1500MHz?
    Guess what...PPGA/FCPGA/FCPGA2 were the same socket (s370).
    Now...SocketA ranged from 800MHz Durons to 2GHz AthlonXP 3200+
    P4 start was with socket 423, but intel soon abandoned it for 478, however there were some adapters for some CPUs which allowed s478 CPUs to work on s423 mobos.
    AMD with A64 introduced single channel DDR platform on s754. Later in 939 there was enhancement with dual channel and dual core. But then DDR2 appeared with quite low prices - so they moved to AM2.
    Intel brought LGA775, but most chipsets for Prescott couldn't handle Core 2, later C2D FSB800MHz chipsets couldn't handle FSB1066 and 1333MHz C2D/C2Q cpus. And now we get LGA1366, 1156 and some more for the same familly. Well, I guess intel is more disruptive than AMD. I can put PhenomII 810 AM3 to my AM2 mobo on M1695+NF3, some NF3 ASRock users can do that too. AM2/2+/3 is on the best way to be worthy SocketA successor.
  • raden_muaz
    I've been waiting for so long for this phenom ii to come.
    At last, phenom beats i7 in some kind of way.

    Anyway, I never bought Intel for years because:
  • sohei
    there are 5 sokets technically but 2 physically
    my question is : somebody try a am2/am2+ with a am3 cpu?