The Phenom Inspired, Core i7-like, Phenom II

Want to hear something funny? When AMD launched the original Phenom, it was a unique looking architecture, something AMD touted as a significant advantage due to its "native" monolithic quad-core design (four cores, one die). I often argued that it wasn't an advantage, simply because the performance numbers didn't back up AMD's claims. AMD never won a real world desktop benchmark because of the monolithic quad-core design.

Intel followed up with Nehalem (Core i7), a microprocessor that had a very Phenom-like cache hierarchy (four cores, private L2 caches, one large shared L3 cache), but with much better performance.

Phenom II builds upon the same architecture as the original Phenom, hardly changed, but improves on a few key limitations. This isn't a new microarchitecture, this is a 45nm shrink of Phenom. In a sense, AMD gave up on improving the original Phenom. Early on after Phenom's release AMD went head in the sand and did whatever was necessary to make the 45nm transition perfect. Deneb, as it was called internally, had to succeed - because AMD as a company wasn't going to survive on the backs of the GPU division forever. It's somewhat ironic that Intel was able to execute a better Phenom-like microarchitecture before AMD.

Processor AMD Phenom II AMD Phenom Intel Core i7 Intel Core 2 Quad Q8xxx/Q9xxx
Manufacturing Process 45nm 65nm 45nm 45nm
L1 Cache 64K + 64K per core 64K + 64K per core 32KB + 32KB per core 32KB + 32KB per core
L2 Cache 512KB per core 512KB per core 256KB per core 2x3MB, 2x4MB or 2x6MB
L3 Cache 6MB 2MB 8MB -
Transistor Count 758M 450M 731M 456M (6MB/8MB L2) or 820M (12MB L2)
Die Size 258 mm2 285 mm2 263 mm2 164 mm2 (6MB/8MB L2) or 214 mm2 (12MB L2)

The above chart details the specifications for the current AMD and Intel quad-core offerings, and here we see a problem. Phenom II and Core i7 are around the same die size and have similar transistor counts, yet Core i7 sells for $284 - $999 while Phenom II sells for $235 - $275. The part that Phenom II actually competes with is the Core 2 Quad Q9400 (and perhaps the Q9550; more on that later), and that's a ~36% smaller die. This is the downside to AMD's pricing strategy; while it's great for consumers it's not particularly great for AMD's profit margins. The other thing to keep in mind is that at 214 mm2 Intel has an entire line of quad-core processors that, in theory, could be moved down the price list if the price wars of 2008 were to continue into 2009.

The move to 45nm was severely needed as you can see by the table above. AMD and Intel seem to agree on the right way to build a quad-core processor today: four cores with individual L2 caches (or one shared L2 per two cores on Intel) behind a large global L3 cache. Intel, however, waited until the 45nm transition was complete to move to that sort of an architecture in order to outfit the chip with a large enough L3 cache. AMD jumped the gun early with Phenom and was forced to limit its L3 cache size to 2MB on 65nm. Finally, with the move to 45nm, Phenom II boasts a 6MB L3.

The transistor counts of Phenom II and Core i7 are surprisingly close, as are the die sizes. The two chips are designed completely differently, but the end result is similarly sized processors. Note that both Phenom II and Core i7 are too big for high volume mainstream markets; the die size would need to be around half of what it is now to address those markets. AMD and Intel will do so by introducing dual (or triple in the case of AMD) core versions at 45nm and then transitioning almost exclusively to quad-core at 32nm.

Phenom II also marks AMD's return to the >$200 CPU market. The two parts launching today are the Phenom II X4 940 and the Phenom II X4 920, priced at $275 and $235 respectively.

Processor Clock Speed Uncore Clock L2 Cache L3 Cache TDP Price
AMD Phenom II X4 940 3.0GHz 1.8GHz 2MB 6MB 125W $275
AMD Phenom II X4 920 2.8GHz 1.8GHz 2MB 6MB 125W $235
AMD Phenom 9950 2.6GHz 2.0GHz 2MB 2MB 140W $174
Index Phenom II's Secret, In Pictures
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  • TravisChen - Thursday, January 08, 2009 - link

    http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...

    What's the system configuration of the Power Consumption test and which software did you run for loading the system?
    Reply
  • Clauzii - Thursday, January 08, 2009 - link

    2009 is going to be very interesting for AMD. The foundry layoff should give them some air to breathe and concentrate on the CPU designs. Reply
  • Skobbolop - Thursday, January 08, 2009 - link

    AM2 support sounds good, but as far i can see very few mobos with AM2 chipset acually supports phenom CPU's... too bad..

    i was hoping that i could upgrade with my MSI K9N Platinum.. :(.. this sucks..
    Reply
  • Thorsson - Thursday, January 08, 2009 - link

    Performance isn't really any better, except in a couple of tests, than C2D chips that are 18 months old, so there's no reason to upgrade for a large chunk of us, and most of the rest will want i7.

    They need a top end chip that compares to the top end i7 like the 4870 was to the GT280. And this is some way from that. It's like the 4870 was competitive to the 9800GT, and was the same price as well.

    With no upgrade path this looks like one strictly for the fanboys at the moment.
    Reply
  • calyth - Friday, January 09, 2009 - link

    Ha. I'm not quite sure whether I hsould try to respond to this, but sure...

    It's a non-trivial task to completely redesign the cores themselves, and I'm not even sure whether they could, say cut out the core, and drop in a new one. It's easy for us sideliners to say they need to improve, and quick, but they need to design a new one that has a much better IPC, with speed, not haste.

    How is this with no upgrade path? This provides an upgrade path for boards up to AM2, which is good enough. With the AM3 versions coming out, people could drop the AM3 version into an AM2/AM2+ board, wait if necessary until DDR3 prices falls some more, and swap to a newer board with DDR3. And now they've a spare computer.

    Look at the i7 prices. Friend of mine just spent 2k for an i7. Sure, he's having fun compiling and playing games with impunity, but I don't think it's the best use of money. Also, C2D is dead. You can't put an i7 into and C2D board, and there's still a good amount of people with older boards that could have a drop in boost.
    Reply
  • Atechie - Thursday, January 08, 2009 - link

    If the CPU had been relased just after Core2, then it might have been a good CPU.
    But today, after 2 years, AMD's "native" quadcore still can beat the Core2 clock for clock...that is more than sad.

    All Intel needs to do now is slash prices of Yorkfield until their i5 socket 1156 dualchannel DDR3 comes out, and they still got AMD by the balls.

    To little, to hyped, to late...
    Reply
  • Sunrise089 - Thursday, January 08, 2009 - link

    This is silly. If the CPU had come out in Summer '06, it would have been god-like. Quad core vs dual-core, higher clock speed, equal or better overclocking, very competitive clock-for-clock, and on a smaller and cooler process.

    What you could say was that if it came out right as Peryn launched it would be a close race...but Peryn improved lots of stuff over Conroe, so it isn't fair to say AMD is 2 years behind.
    Reply
  • Denithor - Thursday, January 08, 2009 - link

    I think that's what Atechie's getting at. Intel took the right path by just cobbling together two dual-core processors to make a quad, while AMD spend excessive time and God only knows how much cash to develop a "monolithic" quad. Which then rolled over and played dead.

    Hopefully AMD has learned from its mistakes. Otherwise Intel may not have much competition in the near future. What's AMD trading at again, these days?
    Reply
  • Proteusza - Thursday, January 08, 2009 - link

    I dont know, this doesnt do it for me. I'm a massive AMD fan - I run a 5600+ right now, my previous CPU was an XP 2400+.

    What is it now, 2 years since the Core 2 Duo was released? And AMD still cant match in clock for clock performance? After the monumental flop that was Phenom, massive delays, poor performance, high power consumption, the TLB bug, patchy backwards compatibility (my MSI K9N mobo with the Nforce 570 SLI chipset cant run AM2+ chips, but the equivalent Asus can), they launch the Phenom II, and the best I can say about it is that is that its acceptable. Acceptable. Not Phenomenal. Just acceptable. Price vs Performance wise, it gets the job done, mostly, sort of. Throw newer game engines at it and even the Q9600, that old workhouse, can beat it.

    Its not that Phenom II is a terrible processor. Its not. Its just not what I expected AMD to launch, many months after the flop that was Phenom. I expected something that could at least beat a 65nm Core 2 Duo, if not a Nehalem.

    As Anand hinted at, Intel is going to drop prices, which they can afford to, forcing AMD to do likewise, which they cant. AMD's die size is similar yet their margins are far smaller. Intel's next CPU will be the die shrink of Nehalem, what will AMD release? Will it even match Penryn? I can only hope.
    Reply
  • KikassAssassin - Thursday, January 08, 2009 - link

    Since the Phenom II was always known to just be a die shrink with some optimizations, you were setting your hopes way too high if you thought it was going to compete directly with the i7. AMD needed this launch to keep them in the game, and it looks like it's probably just good enough to be able to do that. We probably won't be seeing any big breakthroughs from AMD until Bulldozer, so we just have to hope that this architecture will have enough headroom in it to last that long. Reply

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