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
45nm and Low Power Consumption
Built on a 45nm process, Phenom II is finally using the same feature size as Intel’s processors. Intel’s 45nm caches are a bit smaller than AMD’s, but it’s no longer a 65nm vs. 45nm playing field - things are much more even. However, AMD and Intel’s approaches to 45nm differ considerably.
Circuits are placed on silicon wafers through the use of photolithography. Light is shone on a mask, and the light then makes it through the mask and etches the circuits on the silicon wafer. The wavelength of light used determines the minimum feature size of the circuits on the wafer. By itself, 193nm wavelength deep ultra-violet light is only useful for circuit feature sizes down to 50nm. To reach 45nm and beyond you need to do a little more.
AMD uses immersion lithography, which places a liquid between the source of the light and the wafer itself. The liquid increases the resolution at which the light can focus, allowing for smaller than 50nm feature sizes with currently available tools. Immersion lithography isn’t a performance enhancing feature; it’s simply one that makes it possible for AMD to manufacture at 45nm.
Intel claims that immersion lithography isn't necessary at 45nm and doesn't use it. Intel uses a technique known as double patterning but only on the gate layer of the chip. Intel’s approach requires higher mask costs but can result in a high yield 45nm chip without the use of immersion lithography. AMD’s approach should be more cost effective initially since you have to create fewer masks, but Intel’s scale of 45nm production should help offset that. For what it's worth, the double patterning has been in use since Intel's 65nm process.
Remember Intel’s high-k + metal gate transistor announcement? That’s still a feature advantage that Intel holds at 45nm. The new transistors make sure that current doesn’t flow when it’s not supposed to, reducing power consumption.
The two processes, despite both being 45nm, are different enough that they aren't the same despite having similar feature size - but comparing manufacturing processes is beyond the scope of this article.
A Power Efficient Phenom?
When Phenom first hit, not only was it underperforming, but it also drew far too much power. Combine that with a CnQ mode that robbed users of performance and you ended up with a CPU that was hardly power efficient. Just like the cache deficiency, Phenom II fixes this.
With Core i7, Intel developed power gate transistors that can completely shut off an individual core that’s not in use. Intel’s cache hierarchy is inclusive so any data stored within a core’s L1 and L2 caches is already duplicated in the L3 cache; if a core isn’t in use it can be shut down and there’s no need to wake it back up until it’s needed again.
Remember, Phenom II isn’t a complete redesign, so AMD couldn’t work on a similar technology. Despite that, idle power in Phenom II is greatly improved. When a single core is idle, the contents of its L1 and L2 can be flushed out to L3, allowing the processor to halt the clocks to that core - thus reducing power. The core will still consume leakage power, but it’ll be far less than if it were running at the lowest p-state. Intel introduced something similar back in the Conroe days, except data from L1 was pushed out to L2 before the core was powered down since there was no L3. Nehalem still has the ultimate in idle power thanks to Intel’s power gate transistors, but as you can see below Phenom II’s idle numbers are quite impressive.
| Processor | Idle Power | Load Power |
| AMD Phenom II X4 940 (3.0GHz) | 109.6W | 189.7W |
| AMD Phenom 9950 BE (2.6GHz) | 124.2W | 210W |
| AMD Phenom X3 8750 (2.4GHz) | 127.5W | 210W |
| AMD Athlon X2 6400 (3.2GHz) | 101W | 195W |
| Intel Core i7-965 (3.2GHz) | 99W | 199W |
| Intel Core i7-920 (2.66GHz) | 95W | 168W |
| Intel Core 2 Extreme QX9770 (3.2GHz) | 135W | 219W |
| Intel Core 2 Quad Q9400 (2.66GHz) | 126W | 174W |
| Intel Core 2 Quad Q8200 (2.33GHz) | 134W | 168W |
| Intel Core 2 Duo E8600 (3.33GHz) | 124W | 157W |
Note that while Penryn’s idle power isn’t nearly as low as Phenom II, this has more to do with Penryn’s lowest operating frequency. Phenom II’s minimum p-state is only 800MHz, compared to 2.0GHz on Penryn. Load power is also impressive, not quite Nehalem impressive but definitely competitive with Penryn at least.
In load power, Penryn still has the advantage. The Q9400 draws 174W compared to 190W for the Phenom II X4 940. The Core i7 is still the most power efficient of the two, as the i7-920 draws less power and is faster than the Phenom II X4 940.
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Beno - Monday, January 12, 2009 - link
fanboys help keep them alive.if more ppl started looking at AMD again, then Intel will be scared, so us the consumers will be happy because of prices.
intel has been greedy and overpriced their c2 because there was no competetion at that time.
garydale - Friday, January 9, 2009 - link
I generally buy AMD processors for two reasons. The first is that I am not a gamer so I'm looking for cost-effective business application solutions. I'd rather double the memory than increase the processor speed, so AMD works well at the price points I build to.Secondly, I believe in the need for competition. With the power PC processor virtually absent from the consumer market and there being little else to choose from for the desktop market, AMD is Intel's only real competitor. So long as AMD has chips that are good enough to compete with Intel's on price/performance, I prefer to buy them.
If Via got their Cyrix processors up to a decent speed, I might be tempted to switch to them, but let's face it, they don't really compete in this market. So in a two-way race, we need to put our money behind the underdog to prevent a monopoly.
I've been buying ATI cards too for similar reasons. Nice to see that AMD's making advances in both areas.
To be clear, I've got nothing against Intel, at least not since the Pentium fiasco, but I think everyone will agree that having multiple firms competing is better for consumers than having one company dominate (Windows 95, 98, Millenium Edition, Vista come to mind). :)
aeternitas - Friday, January 9, 2009 - link
Much of your post should go next to the Webster definition of "AMDfanboi"If you want true competition, buy the better product. I got my sweet A64. I will now consider P2 over a C2D, but because of price/performance/watt alone.
Certified partner - Friday, January 9, 2009 - link
"Blender is one of the few tests that doesn't strongly favor the Core i7, in fact it does not favor them at all. Here the Core 2 Quad Q9650 is the fastest processor, followed by the Phenom II X4 940 and the Phenom II X4 920."http://www.techspot.com/review/137-amd-phenom2-x4-...">http://www.techspot.com/review/137-amd-phenom2-x4-...
"Blender shows Phenom II less competitive than the other 3D rendering tests we've seen thus far."
http://www.anandtech.com/cpuchipsets/showdoc.aspx?...">http://www.anandtech.com/cpuchipsets/showdoc.aspx?...
Both can't be true. Explanations would be highly appreciated. I suggest, that anandtech ask techspot about the test settings. Blender is capable of using several threads but I'm not sure wether the optimization is automated. Please, play with the settings. For example, 8*8 (render) tiles can benefit from 8 threads while 1*1 can't.
Max1 - Friday, January 9, 2009 - link
How much money has paid Intel to you for this "testing"? You have tested productivity of processors only on two games. In both games productivity of Core 2 is above. In one of them much more above, but it happens seldom. Other tests show, that productivity of Core 2 Quad in part of games is above. In part of games productivity Phenom II of same frequency is above. Why there is so a lot of coding and synthetic tests where Intel is faster, and as always there are no other applications? Why you continue to say lies, as earlier liars for money of Intel that Northwood is ostensibly faster, than Barton.strikeback03 - Friday, January 9, 2009 - link
I'm surprised how long it took the fanbois to start commenting on this article. Didn't really get rolling until several pages into the comments.JimmiG - Friday, January 9, 2009 - link
Bit disappointing that it's still slower than Core2 clock for clock. But given the performance of the original Phenom, I think the CPU performs as expected. A big leap for AMD. Unfortunately for them, Intel made an even bigger leap when they switched from Netbust to Core2.Also a bit concerned about this supposed "backwards compatibility". Many of the original 790FX boards, my M3A32-MVP Deluxe in particular, will not work with AM3 CPUs because Asus does not plan on releasing a BIOS update. Of course that's the fault of second-rate mobo companies like Asus, and not the fault of AMD. I'll probably end up getting a DDR2 PII-940 to replace my X4 9650, but I'll wait until the prices have dropped some.
anandtech02148 - Friday, January 9, 2009 - link
Just wait till Am3 socket comes out, Intel will have to make a slight cheaper version of x58chipset. Is that sweat i see on their forehead?Amd buy Via's Nano and give them a 2 prong attack.
RogueAdmin - Friday, January 9, 2009 - link
AMD has gone a long way to improving the performance of its processors, and everyone should go out and buy them. They need our support, and without it we will have to put up with whatever Intel decide to give us. And everyone here I think remembers the P4 days, let them not come again!The AM2 /2+ /3 platform is by far the easiest upgrade option. No need to worry if your NB chipset supports the latest FSB or RAM, because its all integrated into the CPU. A feature than Intel has copied in its new i7. Along with the monlithic quad core design, and level 3 cache. Also do not forget that AMD released the first x86-64 CPU, and intel basically complied to its x86-64 code to be compatible with the software developed for it.
i7 is fast, very fast. But do you need that kind of performance in your everyday life? i7 is designed for workstation's hence the benchmarks of video encoding and 3D applications. Gamers would be better off getting a top of the line GPU. Is your CPU 100% utilized 24/7?
I saw a comment about the 2 year old Core 2 Quad being faster, only in Far Cry 2, that one test. And I would rather play Crysis anyday.
Since its release Intel has tweaked the performance of these with new cores no end.
Sorry I digest.... lol
Keep things competitive, buy AMD. Fanboy or no, let the price wars rage on.
aeternitas - Friday, January 9, 2009 - link
1. Most people use their everyday system to *work* too.2. Dont compare i7 to P2. Youll just look like youre really reaching and a fanboy.
3. You dont -Need- anything better than a A64 for everyday tasks. Depending on how long you wanna wait though, you will go to a better system. That point about not -needing- better hardware has always been ridiculous and only applies to grandmas and people that use the computer for browsing and music. Those people dont care about this area in computer so its moot!
P2 is great, but be realistic. Its competing against C2 right now. Comparing technicalities and -who was firsts- doesnt provide more FPs in anything. It just makes for flame fodder. The numbers speak for themselves and I think this article did a good job in putting the P2 in its place. As a great alternative for people looking to upgrade from older than C2 hardware.