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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Walkeer - Thursday, October 15, 2009 - link
Super, so because MS Vista has a really bad and stupid CPU scheduler, AMD had to disable perfectly legit and smart power saving feature = CnC per core rather than per chip. I really love windows! I expect that CnC per-core caused no problems under linux for example....CuE0083 - Sunday, April 26, 2009 - link
I have been a reader of this site for a few years (first time commenting) and I just wanted to know how you guys determine that a particular processor is a good overclocker.1) Do you guys try overclocking multiple chips?
2) Do you just walk into the store, pick a random chip, and try overclocking it?
3) Or does AMD send you a chip?
v12v12 - Thursday, July 23, 2009 - link
All this bickering and nick picking—when to me the solution seems simple.All the poor folks clamoring about numbers they COULD NOT EVER POSSIBLY tell the difference if using Intel Vs AMD in a dboule-blind test! None of you can tell the measurable diffs in FPS and temp. It's all little programs with numbers telling you there's a difference. So wtf is all the fus about?
Phenom-II is for people that already have an old AM2 rig and want to upgrade. But you forget that your old, slow ass mobo chipset and antiquated ram wouldn't even come close of a newer Intel system period.
A Brand NEW Phenom-II would "compete," but it barely does that. And as prices drop Phenom-II is losing even more ground as someone with an intel 775 can spring for a fast Quad-core, while you're stuck with the SAME OLD MOBO and RAM DERRRRR?
Stop all the nit-picking and bemoaning over Intel.
Does it make sense to scrap your current AMD rig for a completely new Intel unit?
YES = If you're doing video/AV editing and plan on getting an i7/i5 or if you’re not broke!
NO = If you currently have an AMD and need some extra horse-power.
But to falsely rationalize your purchase/mindset by suddenly putting the i7 into the "it's SO expensive" BS category; you're BROKE, you have no say about price. Get a real job and stop spending money on other nonsense and SAVE up like smart people do. It's YOUR own fault you cannot afford a damn $1100-1400 computer: that's NOT a lot. Just b/c YOU cannot afford it doesn't mean there's something "wrong" with i7.
You're comparing a 2yr old Q6600 against AMD's newest unit LOL? That's like a car magazine comparing the newest lambo to a 2 year old Ferrari etc. BUT PRICE OMG... Prices steadily go DOWN, thus folks with 775 can still upgrade to 6700, 6800 and so forth.
I'm glad AMD is "sort of" showing a rally to CATCH UP... BUT... when you buy into INTEL you're buying into a PROVEN ROADMAP OF PERFORMANCE VS AMD: you're buying into a mystery grab-bag of performance PROMISES.
Geesh. Just get the Phenom-II if you cannot afford the i7. Nobody with sense is talking about going from a Q6600/9xxx to 2 year behind the pack Phenom. This is just sophomoric nonsense.
Common-sense would tell you:
1) GET A BETTER JOB (education/certs etc)
2) Stop spending money on other hobbies and misc junk
3) STFU already and improve your financial situation, THEN you have a say. It's YOUR fault you don't have enough for a paltry $1200 machine. WHO doesn't have $1200? If you don't you haven't EARNED the right to complain. Complain b/c it's someone else's fault - I'm betting it's mostly your own lack of saving & discipline that's the problem.
None of you may like or agree w/me, but guess what? I don't care b/c I HAVE $1200 to spend so Fsck it I'm happy. Stop drinking, doing drugs, going out, blowing money on cable-TV and crap, for a change? Most of you are guilty of 1 or more of these frivolities.
Honestly THINK about what you’re saying here? You’re complaining about a superior i7 that is too expensive to do WHAT— play some damn video games? So your rationale is to do what? Buy a new or CPU upgrade to do the same? So THUS instead of continually saving to get the best… You BLOW your loads for inferior technology… and so the cycle continues. You’re NOW BROKE AGAIN and behind. Maybe you’ll start saving once again and come out of the wood work 2-3yrs later and STILL be complain once again “OMG it’s TOO EXPENSIVE” “I’ll by the cheap crap instead!”
LMFAO NOW THAT IS Ludicrous!
goofbud - Tuesday, December 6, 2011 - link
Are you serious dude?It ain't the money. I know. I have money. I also have a lambo a porche and an evo. I like testing AMD because they give us "certified" techs something to tinker with and work on. AMD is a brand for builders and true techs like to tinker with a processor and see how far it can go. Even when I was in high school I owned 486's which were the latest and greatest that time. I had an INTEL PC and it sucked dirt once Microsoft came out with windows. Maybe Intel is ahead now but AMD is catching up. They can create the ultimate processor but they don't have to. Not yet.
BTW, watch how you talk. Be considerate. It ain't the money man. I can afford to buy as many alienware pc's I want. But I don't. Am I a gamer? Yes! I have a powerful system now and am happy I did not spend a lot of money on it. See, this is the thing. If you are smart you just don't want to buy the fastest CPU and fastest RAM that comes out. It's like buying an PS3 for $6,000.00 on ebay just because you want to be the first to play it. That is stupid.
People buy AMD because they are tweakable. They try to buy the cheapest parts out there, tweak it, and see how far it can go. Makes sense?
So what if you have the fastest computer in the world. If you don't use it everyday you just wasted money.
Understand now kid. Now STFU and Go to your room!
sandstones - Wednesday, March 25, 2009 - link
I know that we should look at relative sysmark scores, but I'm still puzzled by the higher scores in this batch of tests, compared to those done in April 2008.For example the top performer from April - Core 2 Duo E8400 got a score of 161 on Overall in April 2008, and 191 in Jan 2009. The X4 Phenom 9750 went from 126 to 148. Other CPU's in both tests had similar differences. That's a bigger percentage difference than what gets used to debate whether Intel or AMD is better.
Anand - any comments on what caused such a large difference?
Amitjakhar - Friday, February 20, 2009 - link
http://www.overclockersclub.com/reviews/phenomii94...">http://www.overclockersclub.com/reviews/phenomii94...After overclocking it really comes near and sometime it gets better performance them Core i7. Which is good. AMD has done superb job and they are in the right direction. Next black edition will make Intel so worry they have to go to work again.
Amitjakhar - Friday, February 20, 2009 - link
Phenom II is showing power much better then here. To me it seems they have not done the testing properly. You better check out this link and find how its performing genuinelyhttp://www.guru3d.com/article/amd-phenom-ii-x4-920...">http://www.guru3d.com/article/amd-phenom-ii-x4-920...
salem80 - Tuesday, January 27, 2009 - link
The Q9400 are 126W~174W not like what Intel said 95W ?even E8600 (124W~157W) while they say 65W ?
their huge deferent in numbers here .
pcuser123 - Saturday, January 24, 2009 - link
I think the new i7 core sucks compare Phenom II. Just look at the pricing vs performance on those two.Here is the benchmarks http://www.overclockersclub.com/reviews/phenomii94...">http://www.overclockersclub.com/reviews/phenomii94...
gipper - Monday, January 19, 2009 - link
You do the overclocks but don't show us the results? Following overclocking, those stock processors have WIDELY different capabilities.I'd love to see those video encode charts redone with the overclocked processors. That would tell me the TRUE value of the 64x2BE, C2D, Phenom, PhenomII, and i7 relative to one another.
Otherwise, your overclock information borders on worthless.