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
Hooray, AMD is Overclockable Again
Since the introduction of the B3 stepping Phenom that solved the TLB bug (along with improved yields), overclocking a Phenom has been a fairly painless process. This is especially true with the Black Edition series and a well designed motherboard based on the 790FX, 790GX, or 780a chipsets. While the Phenom has not offered the same overclocking headroom as the latest Penryn processors that typically offer a 1GHz improvement on the middle to upper range processors with air-cooling, it is not uncommon to see the Phenom BE series offering a 600~800MHz improvement in clock speeds.
AMD has proven in early demonstrations that the Phenom II x4 will offer overclocking headroom similar to the Penryn series. Early production sample processors have clocked anywhere from 3.9GHz on air to 4.4GHz on water and all the way up to 6.3GHz on LN2. We have matched their results on air-cooling and been impressed with the potential headroom offered by the new 45nm manufacturing process on extreme cooling setups. In fact, the latest retail steppings that AMD displayed this past week showed significant improvements in overclocking headroom compared to the press samples we utilized. Our 940 topped out at 3.9GHz, which is not bad, but after reviewing AMD’s results and seeing some early retail numbers on the forums, the expectation level for air-cooling is now set to the 4.1GHz range with the 920 hitting 3.8~3.9GHz on the right motherboard.
We have retail processors arriving shortly for additional overclocking tests (we will push HTT/NB settings); in the meantime, we have some interesting numbers to present with our press samples. In our overclocking tests today we are utilizing the Phenom II X4 940, Phenom 9950 Black Edition 125W, Core 2 Q9550, and the Core i7 920. Besides having a strong processor, a well-engineered motherboard, premium memory, excellent cooling, and proper power supply are all essential elements in obtaining stable and high clock speeds when overclocking.
With that in mind, we are utilizing the DFI LP DK 790FXB-M2RSH (790FX), ASUS Maximus II Formula (P45), and DFI LP UT X58-T3eH8 (X58) motherboards for testing. We also tossed in the Corsair HX1000 power supply along with memory from Corsair and G.Skill featuring their TR3XGG1600C8D 6GB DDR3-1600 and F2-8800CL5D-4GBPI DDR2-1100 4GB kits respectively. The balance of the test system consists of a WD Caviar Black 1TB HD, Blu-ray drives from Sony and LG, Vista 64 Ultimate, and our ABS Canyon 695 case.
In a twist from our normal overclocking results, we decided to utilize the retail air-coolers from Intel and AMD to provide a more realistic out-of-box experience when overclocking. We based today’s test results on how high we could overclock on stock voltages and then by increasing voltages until we ran out of cooling headroom with the retail coolers.
| Processor | Highest Overclock (Stock Voltage) | Highest Overclock (Overvolted) | % Increase over stock | Overvolted Vcore |
| AMD Phenom II X4 940 (3.0GHz - 1.32V) | 3.2GHz | 3.9GHz | 30% | 1.52V |
| AMD Phenom 9950 BE (2.6GHz - 1.26V) | 3.03GHz | 3.38GHz | 30% | 1.45V |
| Intel Core i7-920 (2.66GHz - 1.32V) | 3.83GHz | 4.0GHz | 50% | 1.35V |
| Intel Core 2 Quad Q9550 (2.86GHz - 1.22V) | 3.48GHz | 3.91GHz | 38% | 1.35V |
We disabled the power management features and manually set the voltages to stock values. Leaving the BIOS settings at Auto will generally result in the BIOS auto-leveling voltages to handle the increased clock speeds for the processor, memory, and bus speeds. We did not get very far with our particular 940 sample as it only reached 3.2GHz resulting in a dismal 7% increase in clock speed. With the exception of the PCMark Vantage TV/Movies test suite and our Flight Simulator X benchmark, this 940 processor passed all other tests at 3.45GHz. The Phenom 9950BE had a 17% increase in clock speed while the i7 920 managed a stunning 50% improvement in clock speed. The E0 stepping Q9550 managed a 23% improvement in core speed.
In our second test, we manipulate voltage settings ranging from the normal VCore/VDimm to VTT/IOH/PCIe until we reached the load limits on the retail air-coolers. Higher-end air-coolers improved clock speeds slightly (3~5%) while dropping core temperatures up to 9C in certain cases.
The clocking situation improved greatly with our 940 once VCore rose to a final 1.52V. We actually hit 4GHz but needed 1.58V to do it. This resulted in a few crashes due to temperatures, but we also noticed our particular CPU sample just was not stable at 4GHz+ even with additional voltages and cooling. The results for the two Intel processors are simply superb in this particular test with the 9950BE managing a respectable 30% improvement in clock speeds, matching that of the Phemom II percentage wise.
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Shadowmaster625 - Friday, January 16, 2009 - link
Why didnt you include an overclocked E5200 in the testing?!?!?!omg this is horrid. How do these $230-$270 CPUs compare to an $85 E5200 coupled with a $105 Gigabyte GA-EP45-UD3R? That combo will easily overclock to 3.8 Ghz on stock cooling. CPU, mobo + RAM all for less than the cost of a Phenom II. And better performance too.
Reynod - Monday, January 12, 2009 - link
Another excellent article Anand.Would you be able to write a short piece on the AM3 socket and the "likely" impact on performance once you have some samples please?
R4F43LZiN - Saturday, January 10, 2009 - link
I wanted to see some Phenom II overclocked gaming benchmarks...zagortenay - Saturday, January 10, 2009 - link
To correct my mistake in above post:"And check the link of very respectable "Guru of 3D" yourself, X4 940 beats Core i7 920 in higher resolutions." Not Core i7 940.
zagortenay - Saturday, January 10, 2009 - link
Great comments Aranthos! AMD did a great job with Phenom II, no doubt about that.Anandtech review is kind of fair and balanced when it comes to giving the final verdict, but the tests are deceiving and unfair as usual.
First of all, as somebody else has already pointed out, they used an average mobo to test Phenom II, while they used expensive enthusiast level mobos for Core2 Quad and Core i7 (230 and 250 Dollars respectively). They could not find an Asus M3A79-T (which is much cheaper at 185$) There is no excuse for that! Either a deliberate move not to show what Phenom II can deliver at its best, or Anand needs to learn a lot from us. Just check the below link to see the performance difference between 790GX and 790FX. Quite some performance difference in some benchmarks and consider that it is still a close competition with an average AMD motherboard.
There IS a difference apparently: http://www.legitreviews.com/article/795/5/">http://www.legitreviews.com/article/795/5/ and it would change some conclusions
And now introducing a classic: Why Core2 Quads run on DDR3 (Yeah, all Core2 Quad users definitely switched to DDR3, lol!) and Phenom IIs run on DDR2? To show the best of Core 2 Quads... So what happens if DDR2 is used also on Core 2 Quads? See yourself below. X4 940 beats Q9550 most of the time and even Q9650 in some applications.
http://www.bit-tech.net/hardware/2009/01/08/amd-ph...">http://www.bit-tech.net/hardware/2009/0.../amd-phe...
I wander what trick they will do with RAMs, when Phenom II AM3 (with DDR3) comes this February.
Anand says X4 940 trails Q9650 and by 28.4% when it comes to Far Cry 2. Is it so? Or? Check the above link again. Even with DDR3 RAMs Q9650 leads by only 4.4%. With DDR2, X4 940 leads this time, with a little margin. Same resolution! Who to beleive?
And check the link of very respectable "Guru of 3D" yourself, X4 940 beats Core i7 940 in higher resolutions. He he!
http://www.guru3d.com/article/amd-phenom-ii-x4-920...">http://www.guru3d.com/article/amd-phenom-ii-x4-920...
So what? Don't get fooled, don't get deceived by the "big brother connections".
Final words: Yes I am a fan boy and I don't pay a penny for Intel!
Aranthos - Saturday, January 10, 2009 - link
I wonder why so many people keep saying "What happened to the AMD from the Athlon64 era? It was whupping Intel!" etc.That AMD is still here. The same AMD that so long ago brought us Hypertransport, the integrated memory controller, native dual-core and the like brought us native quad-core and a three level cache heirarchy a full year before Intel did either. As it turned out, Intel did it better - a fact with which I won't even try to argue. However, AMD is still working.
P1 flopped. It was the most hyped chip in years, and brought all sorts of false promises. All Deneb promised was better overclocking, lower power consumption and more clock-for-clock performance. It did all 3.
I'm not going to say Intel ripped off AMD by using an IMC and a HT-esque high speed interconnect. Granted, AMD did it first, but Intel would have ended up doing it ANYWAY because it is a good idea.
Back to the original topic - we still have the old AMD with us. They're still innovating as always. But, we have a new Intel. One that isn't peddling crappy Netburst chips. New Intel is going out guns blazing, and they have the money to make sure that another P4 doesn't happen.
AMD got lucky back in the P3 -> P4 era. They're gonna have to either pull out a win of epic proportions, or stick to razor thin margins on their chips. Intel has seriously deep pockets, and can easily afford to destroy AMD's prices.
i7 is epic win. But I'm buying a Deneb anyway. Yeah, people are gonna call me a fanboy, and so what. I'm buying a chip made by a company that is facing a company over 50x their size. While they're not a little family run business, I will support them to their dying breath because they need every sale they can get. I like high performance as much as the next guy, but if buying higher performance (in my case at a higher price [I have an AM2+ motherboard]) puts the business a step closer to being one-sided, then Intel can suck it. They don't need my money.
Mathos - Saturday, January 10, 2009 - link
Well, it's not quite a 4800 series equivelent release this time. More like being around the same as the 3800 series was. A good improvement over the hd2000 series cards, in this case a good improvement over the phenom 1.On the other hand I am wanting to see what will happen with the AM3 versions. Should improve scores quite a bit on anything that likes memory speed and bandwidth. I'm also wondering what other optimizations will come with AM3. Gonna wait for that, since I should be getting another nice quarterly bonus around the time those come out. Use a pII 945 on my old k9a2 plat till I can get an AM3 board and DDR3 memory.
Maroon - Saturday, January 10, 2009 - link
This was a great step forward by AMD. After the Phenom flop they had to transition successfully to 45nm or basically fold. They have done that. AMD doesn't have the resources to compete with Intel on the highend right now, but with this release they can compete in the mainstream market where most processors are sold.They're using the same strat that worked for the 4xxx series video cards, performance per dollar.
Megaknight - Friday, January 9, 2009 - link
Have the Intel fanboys noticed that they're comparing a DDR 2 Phenom II to a DDR 3 i7? I know AMD will be slower anyway, but it should close the gap a bit, right?aeternitas - Friday, January 9, 2009 - link
Are you serious? DDR3 might be able to give AMD an advantage overall compared to the C2. But then going DD3 and spending that much money, you might as well go i7 anyway. (unless you're a fanboy)Seriously guys, if you're going t go around comparing P2 to the i7, you need to focus on price! Else you'll look really bad.
P2 is against C2. End of story. You cant sit around theorizing some magical item is going to get a P2 anywhere close to the i7.
Stop defending AMD. They have 18 months of catchup to do and dont need pats on the back and excuses from people like you. They have a good chip and alot of good things in the chip that they dont need to do in the future as they come up with new architecture.