AMD Phenom II X4 940 & 920: A True Return to Competition
by Anand Lal Shimpi on January 8, 2009 12:00 AM EST- Posted in
- CPUs
Socket-AM2, AM2+ and AM3: Backwards Compatibility
AMD fixed the cache size issue, it fixed the power consumption problem, and we even got higher clock speeds with Phenom II. What I didn’t expect was something more. AMD has always been a manufacturer for the customers. Over the past couple of years the problem has been that their processors haven’t really been desired by consumers, but prior to that the AMD that we know and love designed processors for today’s applications with a minimal number of platform changes between processors.
Phenom II carries AMD’s consumer focused nature to the next level. Today’s Phenom II parts are designed for Socket-AM2+ motherboards. AMD doesn’t qualify any of them for use on Socket-AM2 motherboards, but there’s nothing stopping a motherboard maker from enabling support on a standard AM2 motherboard. You will need a BIOS update.
Next month, AMD will launch the first Socket-AM3 Phenom II processors. The main difference here is that these parts will support DDR3 memory. Oh no, another socket, right? Wrong.
Socket-AM3 Phenom II parts will also work in Socket-AM2+ motherboards, the two are pin-compatible. When in an AM2+ board, these upcoming Phenom II processors will work in DDR2 mode, but when in an AM3 board they will work in DDR3 mode. How cool is that?
This unique flexibility is largely due to the work that was done on the DDR2 and DDR3 specs at JEDEC. The number of signaling pins and the signaling pins themselves between DDR2 and DDR3 don’t actually change on the memory controller side; the main differences are routing and termination at the memory socket side. AMD just needed a physical memory interface on Phenom II that could operate at both 1.8V (DDR2) and 1.5V (DDR3) as well as work with timings for either memory technology. The potential was there to do this on the first Phenom, it just wasn’t ready in time, but with the Socket-AM3 Phenom II processors you’ll be able to do it.
While I’m not sure how practically useful the AM3/AM2+ flexibility will be, I’d rather have it than not. Being able to take one CPU and stick it in two different sockets, each with a different memory technology, and have it just work is the most customer-centric move I’ve ever seen either company make. AMD told me that this plan was in the works before the original Phenom ever launched, somewhere in the 2004 timeframe. AMD was active in JEDEC on making the DDR2 and DDR3 specs similar enough that this one-CPU, two-sockets approach could work.
One of the biggest risks AMD faced when it chose to integrate the memory controller was what would happen if there was a sudden shift in memory technology. With the upcoming Socket-AM3 versions of Phenom II, that risk is completely mitigated by the fact that a single chip can work with either memory technology. It gives OEMs a tremendous amount of flexibility to ship systems with either DDR2 or DDR3 memory depending on which is more cost effective. It also ensures a much smoother transition to DDR3.
The downside for AMD is that because Socket-AM3 Phenom II chips are right around the corner, it makes little sense to buy one of these Socket-AM2+ Phenom II processors - at least not until we know the pricing and availability of the Socket-AM3 versions.
Slower North Bridge Frequency for AM2+, Faster when AM3 Arrives
An extra benefit of the Socket-AM3 Phenom II processors is that their uncore (memory controller + L3 cache) will be clocked at 2.0GHz instead of 1.8GHz like the two processors launching today. By comparison the Phenom 9850 and 9950 both have a 2.0GHz uncore clock; AMD had to go down to 1.8GHz to launch the Phenom II at 2.8GHz and 3.0GHz today.
As 45nm yields improve AMD will increase the uncore frequency, but today it's at 1.8GHz and the AM3 chips will have it at 2.0GHz. The Core i7 runs its uncore at 2.13GHz for the 920 and 940, and 2.66GHz for the 965.
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TravisChen - Thursday, January 8, 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?
Clauzii - Thursday, January 8, 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.Skobbolop - Thursday, January 8, 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..
Thorsson - Thursday, January 8, 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.
calyth - Friday, January 9, 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.
Atechie - Thursday, January 8, 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...
Sunrise089 - Thursday, January 8, 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.
Denithor - Thursday, January 8, 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?
Proteusza - Thursday, January 8, 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.
KikassAssassin - Thursday, January 8, 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.