AMD Phenom II X4 940 Black Edition (BE)
Although there are multiple AMD Phenom II choices, we used the Phenom II X4 940 for several reasons. We did not want to use the first-generation Phenom, as it is still based on AMD’s 65 nm manufacturing technology, which cannot compete with the more advanced 45 nm Phenom II when it comes to performance and the best efficiency.
The Phenom II X4 940 Black Edition running at 3 GHz is the fastest model with an unlocked multiplier, which facilitates multiplier adjustments both upward and downward. This allowed us to simulate the Phenom II X4 920 that runs at 2.8 GHz. We will provide the same type of testing with an Intel Core i7 920 system in the days to come. In that case, we chose the entry-level i7 920 in an effort stay away from the faster models that are significantly more expensive. In the case of AMD, even the Phenom II X4 940 isn’t really pricey, so that wasn't as much of a concern.
Phenom II Models
The Phenom II X4 is a modern, high-end desktop processor that is largely a result of AMD switching from 65 nm to 45 nm manufacturing. It increases the shared L3 cache capacity from 2 MB on Phenom CPUs to 4 MB (Socket AM3 models) or even 6 MB (socket AM2+ models).
The die size of all Phenom II models is 285 mm², although the effective cache configuration may vary to increase production yields. In a simple example, a quad-core die with a faulty core can still be modified and sold as a triple-core model. The following table lists all available Phenom II X4 quad-core processors:
| Phenom II X4 Model | Platform | Clock Speed | Cores | L2 Cache | L3 Cache | TDP |
|---|---|---|---|---|---|---|
| 940 | Socket AM2+ (DDR2) | 3.0 GHz | 4 | 512 KB per Core (2 MB total) | 6 MB shared | 125 W |
| 920 | Socket AM2+ (DDR2) | 2.8 GHz | 4 | 512 KB per Core (2 MB total) | 6 MB shared | 125 W |
| 910 | Socket AM3 (DDR3) | 2.6 GHz | 4 | 512 KB per Core (2 MB total) | 6 MB shared | 95 W |
| 810 | Socket AM3 (DDR3) | 2.6 GHz | 4 | 512 KB per Core (2 MB total) | 4 MB shared | 95 W |
| 805 | Socket AM3 (DDR3) | 2.5 GHz | 4 | 512 KB per Core (2 MB total) | 4 MB shared | 95 W |
The following table lists available triple-core Phenom II X3 CPUs:
| Phenom II X3 Model | Platform | Clock Speed | Cores | L2 Cache | L3 Cache | TDP |
|---|---|---|---|---|---|---|
| 720 | Socket AM3 (DDR3) | 2.8 GHz | 3 | 512 KB per Core (1.5 MB total) | 6 MB Shared | 95 W |
| 710 | Socket AM3 (DDR3) | 2.6 GHz | 3 | 512 KB per Core (1.5 MB total) | 6 MB Shared | 95 W |
Processor Flexibility
AMD processors still employ Hyper Transport to link to the system chipset, and they still include a dual-channel memory controller. AMD decided to offer 45 nm Phenom II processors supporting DDR2 and DDR3 memory, and those CPUs are technically based on the same technology.
Socket AM2+ is the latest interface for AMD’s DDR2-based processors. Hence, all AM2+ motherboards will support processors that were designed for this 940-pin socket as long as the motherboard offers BIOS support for the particular model.
The new processors with DDR3 memory controllers build-in require socket AM3, which is a modified version of the same, physical 940-pin socket designed to support DDR3 memory. The neat part of this strategy is that it is possible to purchase a Socket AM3-based Phenom II processor and run it on a socket AM2+ system with DDR2 memory. At the same time, it is not possible to “upgrade” an AM2+-based Phenom II processor to run on a Socket AM3, as the socket utilizes only 938 instead of 940 pins.
Power And Overclocking
All Phenom II processors are fully modern when it comes to power consumption. Some of the available chipsets from AMD and Nvidia (AMD's 780G, 790GX, 790FX, and Nvidia's nForce 750i, 780, i790i SLI) require less power than fully-featured Intel chipsets--usually because the memory controller is part of the processor, benefitting system idle power. Peak power doesn’t differ much from Intel’s offerings, though.
We were able to overclock several AM2+-based Phenom II X4 processors to almost 4 GHz, but all processors we got running at 3.8 GHz or slightly above would switch off the Cool’n’Quiet feature. This function reduces the processor speed and voltage when the CPU is idle, so it runs cooler and requires less power. This was an issue during our efficiency testing, as it would prevent the 3.8 GHz results to be compareble to the slower settings, which worked fine with Cool’n’Quiet. According to AMD, this is expected behavior resulting from manually keying in higher multiplier settings.
hmm not quite what I had expected from the article but still it gives a good insight of what the phenom II can do.
What I expected or rather would have like to see is the way that delivers the most performance, the multiplier oc or high memory bus speed oc etc. Or if a combination of those will deliver the highest oc ratings.
for the rest its a good article which can be used for those who value good performance at an acceptible power usage.
I think that would be a very good follow up article, maybe using the 3.6Ghz speed in different ways ie, overclocking the bus compared to multiplier
Wouldn't go that far. For servers and clusters the advantage was and still is, almost always in AMD's favour what with simplified and more efficient memory controllers, together with lower latencies.
Plus, in some tests the speed difference between the A64 and Core 2 architecture is not that great (with a few tests really showing what the A64 can do). Plus, when Core 2 came out and people were looking for stable, fast chipsets with onboard features..where were they? AMD was streets ahead. AMD is now competing on price, and can more than make up for what is looses in core performance, by offering products are very good prices. In terms of overclocking I got a 2.1GHz AMD part that will do 2.8GHz on a stock cooler and a little bit more voltage..not bad for an 'inferior' product
I think that would be a very good follow up article, maybe using the 3.6Ghz speed in different ways ie, overclocking the bus compared to multiplier
I'd like to see that test incorporate some heavy-multi-tasking as well..really load down all the four cores, as well as the bus as much as possible. Then compare it to the non-native Quad from Intel. Maybe some supplemental information on the way AMD processors work, for people who aren't familiar with them, ie
- base frequency/bus speed
- HT links: CPUCPU, and CPUNB, NBSB
- HT width
- Memory speeds
..how these things relate to each other and whether it's worth clocking some or all of them to see a measurable return in your overclock. Even for experience Intel users this must appear as double-Dutch if they've never used it before.
I like these overclocking results, they look fairly linear, upto a point. Thanks for doing the groundwork so the rest of us can build cheap GTAIV rigs
it is good to see AMD being back into the game. there 45nm parts and new strategy seem to make alot of diffrence. according to fudzilla amd had some changes at the top http://www.fudzilla.com/index.php? [...] &Itemid=66 John Byrne who is known for the succes of the radeon 4k series is now vice president of both GPU and CPU bussiness this might be a good step towards profitability. and you can actualy call the phenom 920 and 940 amds radeon 4850 and 4870 for the cpu market if you like. i have no doubt we can compare the future models such as the 955 part with 3.2ghz of clockspeed to the radeon 4890 in marketing strategy. fudzilla also claimed amd might boost its market share to 30% in Q2 of this year. this is good news indeed and lets hope they finaly break even. I my self might build an amd system soon phenom 920 seems a good choice for its price since i cannot afford a core i7 setup togheter with a radeon 4890 this should be near perfect
i know 4890 might seem a bit more expansive then 4870 but at the place i plan to buy it it isnt even 30 euro diffence with 4870 512mb version. 4890 is known to be considerably faster then 4870 512mb. here are some benchmarks btw http://www.fudzilla.com/index.php? [...] mitstart=1