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Low-Power Phenom IIs: Making HTPC Magic

AMD Athlon II X2 / Phenom II X2 And Low-Power CPU Bonanza
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In addition to the two dual-core processors being launched today, AMD is also unveiling a pair of low-power Phenom IIs: the X3 705e and X4 905e. Both chips run at 2.5 GHz, feature 2 GHz northbridges, and ship in Socket AM3 trim.

Of course, this means they have DDR2 (up to 1,066 MT/s) and DDR3 (up to 1,333 MT/s) memory support, depending on the platform in which you drop them. HTPCs based on the older 780G chipset (like the Maui platform below) will need a BIOS update to support these new processors.


AMD Phenom II X4 905e
AMD Phenom II X3 705e
Intel Core 2 Quad Q8400
CoreDeneb (quad-core)
Heka (triple-core)
Yorkfield-4M (quad-core)
Manufacturing Process
45 nm
45 nm
45 nm
Frequency
2.5 GHz
2.5 GHz
2.66 GHz
L1 Cache (I / D)
64 KB / 64 KB64 KB / 64 KB32 KB / 32 KB
L2 Cache
512 KB/Core (2 MB Total)
512 KB/Core (1.5 MB Total)
2 x 2 MB Shared (4 MB Total)
L3 Cache
6 MB Shared
6 MB Shared
None
TDP (W)
65 W
65 W
95 W
QPI/HT/FSB
4,000 MT/s
4,000 MT/s
1,333 MT/s
Price$195
$125$163


Identical to the existing X3 and X4 processor lines in every way except power consumption, the two low-power models sport 64 KB of L1 data/instruction cache per core, 512 KB of L2 per core, and the same 6 MB shared L3 cache.

Heka: Deneb, minus one coreHeka: Deneb, minus one core

Nominal voltage is between .825 V and 1.25 V (for comparison, a Phenom II X4 940 BE runs between .875 V and 1.5 V). In essence, these are simply Phenom IIs that are able to run at 2.5 GHz “undervolted,” and hence push power consumption down to 65 W TDP levels.  

There is a price premium tied to the lower-TDP parts. The X4 905e is set to cost $195, while the X3 705e will launch at $125. For the price of the 2.5 GHz X4 you could buy a 2.8 GHz X4 920 (a 125 W part, though it'd also require an AM2+ platform), and for the price of the 2.5 GHz X3 you could get a 2.6 GHz X3 710 (a 95 W part). Is it worthwhile to lose 300 MHz in exchange for a near-halving of power consumption? How about losing 100 MHz to drop from 95 W to 65? For the folks concerned with heat output, we have to suspect the frequency sacrifice will be more than welcome for cooler running. Making the same jump in Intel's lineup (from Q8400 to Q8400S) costs an extra $62, pushing you to $245.

Going, Going, Back, Back, To Maui, Maui

I still haven’t forgotten about Part 2 of the HTPC/Windows 7 story I started earlier this year. It’s a sizable project, though, which has involved replacing a TV, replacing a receiver, and testing tons of hardware/software recommended in the comments you left for that first part.

There is one update I can provide right from the outset, though. I started that project with a Phenom X4 9350e quad-core chip running at 2 GHz with a 1.8 GHz northbridge. It included 512 KB total L1 cache, 2 MB total L2 cache, and a 2 MB shared L3 cache.

AMD provided a new BIOS not yet available through MSI that updates the Maui platform to support the company’s new low-power Phenom II X3 705e and X4 905e processors, which sport the same 65 W TDP as the 9350e we were using before. Swapping in the X4 905e bumped the system up to 2.5 GHz with a 2 GHz northbridge, and a 6 MB shared L3 cache.

The difference in performance is actually quite significant—if you’re considering spending more money on a low-power CPU, it’s probably for an environment like this one. And given a choice between the older 2 GHz Phenom at 65 nm and the X4 905e at 45 nm, the newer chip gets the nod. With Cool’n’Quiet and C1E enabled, the X4 905e idled at about 32 degrees Celsius (800 MHz, .95 V) using the quiet SilentFlux Media cooler that AMD shipped with its Maui demo unit.

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  • 28 Hide
    thedipper , June 2, 2009 1:45 AM
    IronRyan21Maybe if AMD would actually bring out some kind of nehalem competitor instead of flooding the cheapo market with variations of the same chips all over the place. There was Athlon 64 X2, brisbane and windsor, then there was Kuma, which was a phenom with 2 cores disabled. Now we got these new chips which are phenom 2s with 2 cores disabled. Lets put the money into some R&D and get somewhere. It seems like AMDs lost traction. sad.


    The low to mid-price segments are the best selling hardware categories.

    Believe it or not, the $100 bang-for-the-buck graphics cards by far outsell the $500 space heater graphics cards. As with graphics cards, $50-100 CPUs by far outsell the $300-1300 CPUs.

    The market that seems like most of the market - the enthusiasts and gamers - is actually not that much of the market share. Businesses building for performance-per-dollar, low-mid performance factory built home PCs, and people building web or media machines... these together outweigh the enthusiast/gamer market.
  • 18 Hide
    Anonymous , June 2, 2009 1:58 AM
    @IronRyan: Why not start your own semiconductor company and show AMD how it's done? Can a similar argument not be applied to Intel's "double cheeseburger" quads, and "single patty" dual-cores? If we even get any non-quad i7/i5s, do you know if Intel won't just do the same thing? In the future, instead of coming up with some lame argument, just post this for each article:

    "Hi, my name's IronRyan, and I like Intel. Go team Intel, yay!!!!!"
Other Comments
  • 28 Hide
    thedipper , June 2, 2009 1:45 AM
    IronRyan21Maybe if AMD would actually bring out some kind of nehalem competitor instead of flooding the cheapo market with variations of the same chips all over the place. There was Athlon 64 X2, brisbane and windsor, then there was Kuma, which was a phenom with 2 cores disabled. Now we got these new chips which are phenom 2s with 2 cores disabled. Lets put the money into some R&D and get somewhere. It seems like AMDs lost traction. sad.


    The low to mid-price segments are the best selling hardware categories.

    Believe it or not, the $100 bang-for-the-buck graphics cards by far outsell the $500 space heater graphics cards. As with graphics cards, $50-100 CPUs by far outsell the $300-1300 CPUs.

    The market that seems like most of the market - the enthusiasts and gamers - is actually not that much of the market share. Businesses building for performance-per-dollar, low-mid performance factory built home PCs, and people building web or media machines... these together outweigh the enthusiast/gamer market.
  • 9 Hide
    jj463rd , June 2, 2009 1:48 AM
    Those Phenom II 905e's and 705e's would be kickass if paired with the upcoming 785g motherboards.
    AMD has some new interesting CPU's.
  • 18 Hide
    Anonymous , June 2, 2009 1:58 AM
    @IronRyan: Why not start your own semiconductor company and show AMD how it's done? Can a similar argument not be applied to Intel's "double cheeseburger" quads, and "single patty" dual-cores? If we even get any non-quad i7/i5s, do you know if Intel won't just do the same thing? In the future, instead of coming up with some lame argument, just post this for each article:

    "Hi, my name's IronRyan, and I like Intel. Go team Intel, yay!!!!!"
  • 9 Hide
    deputc26 , June 2, 2009 2:09 AM
    Anyone else see the Athlon X2 and think that if they underclocked and undervolted it they'd finally have a legitimate mobile contender?
    If they can run 4 cores at 2.5ghz and 8mb cache on 65w they should be able to run 2 cores at 2.5 ghz and 2mb cache at less than 32.5w.
  • 2 Hide
    rdawise , June 2, 2009 2:33 AM
    Interesting article...I'm glad you put this against the E6300. I haven't seen much about this chip. It as if Intel just snuck on onto the market. I wonder how high of an overclock you can get with it....

    Onto the article, it seems as if the Phenom II x2 550 BE would a great chip in a value gaming rig. If you could unclock the extra cores and get it stable, you'd be one lucky man. Can't wait till see these on the Egg...
  • 0 Hide
    cangelini , June 2, 2009 2:38 AM
    Quickest Pentium, only one with a 1066 MHz bus, disappointing that it's missing some functionality, though.

    Anyone else reminded of GeForce 2 MX when they see how Intel is positioning its mainstream chips these days? I'm all for differentiating with performance to drive down price (even cutting performance-oriented features, like Hyper-Threading), but don't start shedding the actual capabilities of an architecture to handicap it.
  • 2 Hide
    Anonymous , June 2, 2009 3:14 AM
    I would find the Phenom X2 550 interesting because many of the programs I still run today are singlethreaded.
    These programs benefit more from a higher clockrate than more cores.

    Keeping this in mind, and the fact that an OS doesn't (spectacularly) boot faster with more cores, I think the X2 is a great buy.
    I'm a bit dissapointed at the powerdraw. For a HDTV box you don't necessarily need to buy a Radeon 4850. Perhaps a lower powerdraw (and price) in the 4770 or 4670 will be better.
    To playback full HD (1080p) I suppose a Radeon HD 2900XT would be enough.
    Add office tasks, internetting, some photoshop, and casual gaming on a 22"monitor (1680x1050 pix), and a Radeon 4670 would be enough in most cases.
    If you have a 24" monitor (1920x1200 pix) a Radeon 4770 would do.
    Only when latest gaming is concerned should you go for a Radeon 4870 or a 4890.
  • -2 Hide
    Gin Fushicho , June 2, 2009 3:16 AM
    Cant...wait...for...AthlonII.
  • 0 Hide
    cangelini , June 2, 2009 3:24 AM
    Pro, for an HTPC, you'd be fine with a 4670, more than likely. The challenge will be building a system able to keep that setup cool enough. The Maui box with the 905e was *near-silent* but a discrete card would have wrecked this, and a 4670 is almost too much card to be passively-cooled (a la Ultimate-style) without better airflow in the case.
  • 0 Hide
    billybobs , June 2, 2009 3:27 AM
    IronRyansSister@IronRyan: Why not start your own semiconductor company and show AMD how it's done? Can a similar argument not be applied to Intel's "double cheeseburger" quads, and "single patty" dual-cores? If we even get any non-quad i7/i5s, do you know if Intel won't just do the same thing? In the future, instead of coming up with some lame argument, just post this for each article:"Hi, my name's IronRyan, and I like Intel. Go team Intel, yay!!!!!"


    Is this guy serious? He counters another reader's argument by taunting him? Seriously.
  • -3 Hide
    WheelsOfConfusion , June 2, 2009 3:35 AM
    Huh, I had assumed that the new Athlon line was just going to be Phenom IIs with cache/cores disabled. I guess this dedicated design is just a more efficient way to sell silicon than disabling good chips?
  • 1 Hide
    rooseveltdon , June 2, 2009 3:36 AM
    billybobsIs this guy serious? He counters another reader's argument by taunting him? Seriously.

    the othe reader did not have much of an argument to begin with so he deserved the taunting
  • 0 Hide
    hunter315 , June 2, 2009 3:53 AM
    A performance per watt graph would have been nice especially as this was an article comparing lower powered processors as most of us dont run ours at full load for extended periods of time.
  • 0 Hide
    buzznut , June 2, 2009 3:56 AM
    Wow! I am waintin til the price comes down on the 905e, then I'm gettin one. For htpc build, It looks mighty tempting.
  • 2 Hide
    Anonymous , June 2, 2009 3:59 AM
    All this like many other toms articles show me there is not much difference between closely released proximity hardware!
  • 0 Hide
    cangelini , June 2, 2009 4:07 AM
    WoooooooooooooAll this like many other toms articles show me there is not much difference between closely released proximity hardware!


    When a release is incremental and evolutionary in nature, that's a pretty safe bet. There's no use in us embellishing the differences for theatrical effect now, is there?
  • 3 Hide
    Anonymous , June 2, 2009 5:12 AM
    @BillyBob: IronRyan posts an equally pointless pro-Intel fanboy comment everytime any article is posted, I couldn't take the waste of LCD screen space any longer, somebody had to say something.
  • 1 Hide
    MAD4AMD , June 2, 2009 5:47 AM
    Hit me with something Intel! And hit me with good/cheep or you may lose mainstream very quickly...
  • 7 Hide
    ohim , June 2, 2009 6:41 AM
    Is is me or iTunes shouldn`t be used as a benchmark since it`s beeing developed by apple wich uses only Intel CPU`s, and lame audio encoding ... i mean look at the other 2 multimedia programs used and look at those 2.
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