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Testing MethodologyNow that we know how far our Phenom IIX4 920 can be overclocked with air-cooling, we decided to check theperformance level we could achieve with an overclocked CPU. The maingoal was to find out if the new AMD processor could become a better buyfor overclockers than quad-core Intel CPUs from the same price range.So, the main action during this test session will be about the side byside comparison of Phenom II X4 920 overclocked to 3.72 GHz againstoverclocked Core 2 Quad Q8300 and Core 2 Quad Q6600. Intel set theprice point for these processors at $183, while Phenom II X4 920 isofficially priced at $195. Moreover, we have also included a moreexpensive Core 2 Quad Q9300 processor. Although it has almostcompletely disappeared from the official price-list, it is stillretailing widely for a somewhat higher price than that of Phenom II X4920.
As we have already mentioned in our previous reviews,the overclocking potential of junior Intel processors from Q8000 andQ9000 series is determined not by the frequency potential of thesemiconductor dies, but by the ability of the chipsets and mainboardsto ensure stable operational conditions at high FSB speeds. Therefore,we decided to test our Core 2 Quad processors with a popular ASUS P5Q Pro mainboard.It allows increasing the FSB frequency to 475 MHz for quad-coreprocessors. So, Core 2 Quad Q8300 and Core 2 Quad Q9300 with a 7.5xmultiplier were overclocked to 3.56 GHz (7.5 x 475 MHz) in order to beable to compete against Phenom II X4 920. It is the average frequencythe owners of these processors can count on.
Theprevious-generation quad-core Intel Core 2 Quad Q6600 processor isinitially designed to work with 266 MHz bus, so its multiplier ishigher and equals 9x. So, its overclocking potential was not limited bythe mainboard, although high heat dissipation wouldn’t let us push itsfrequency over 3.6 GHz (9 x 400 MHz).
To get a general idea ofoverclocked processors’ performance we included a few high-end CPUs intheir nominal mode: Core 2 Quad Q9650, Core i7-920 and Core i7-940. Youwill also see the results demonstrated by Phenom II X4 920, Core 2 QuadQ8300, Core 2 Quad Q9300 and Core 2 Quad Q6600 processors in theirnominal mode. They will help us estimate the performance gain fromoverclocking.
As a result, we put together three different platforms on 7 processors:
1. AMD Socket AM2+ platform:
- CPU: AMD Phenom II X4 920 (Deneb, 2.8 GHz, 6 MB L3);
- Mainboard: Gigabyte MA790GP-DS4H (AMD 790GX + SB750).
- Memory: GEIL GX24GB8500C5UDC (2 x 2 GB, DDR2-1067 SDRAM, 5-5-5-15).
- Graphics card: ATI RADEON HD 4870.
- HDD: Western Digital WD1500AHFD.
- OS: Microsoft Windows Vista x64 SP1.
2. Intel LGA775 platform:
- CPUs:
- Intel Core 2 Quad Q9650 (Yorkfield, 3.0 GHz, 333 MHz FSB, 2 x 6 MBL2);
- Intel Core 2 Quad Q9300 (Yorkfield, 2.5 GHz, 333 MHz FSB, 2 x 3 MB L2);
- Intel Core 2 Quad Q8300 (Yorkfield, 2.5 GHz, 333 MHz FSB, 2 x 2 MB L2);
- Intel Core 2 Quad Q6600 (Kentsfield, 2.4 GHz, 266 MHz FSB, 2 x 4 MB L2).
- Mainboard: ASUS P5Q Pro (Intel P45 Express).
- Memory: Corsair TWIN2X4096-8500C5 (DDR2-1067 SDRAM, 2 x 2 GB, 5-5-5-15).
- Graphics card: ATI RADEON HD 4870.
- HDD: Western Digital WD1500AHFD.
- OS: Microsoft Windows Vista x64 SP1.
3. Intel LGA1366 platform:
- CPUs:
- Intel Core i7-940 (Bloomfield, 2.93 GHz, 8 MB L3);
- Intel Core i7-920 (Bloomfield, 2.66 GHz, 8 MB L3).
- Mainboard: ASUS P6T Deluxe (Intel X58 Express).
- Memory: Kingston HyperX KHX16000D3K3/3GX (DDR3-1333 SDRAM, 3 x 1 GB, 7-7-7-20).
- Graphics card: ATI RADEON HD 4870.
- HDD: Western Digital WD1500AHFD.
- OS: Microsoft Windows Vista x64 SP1.
Four processors out of seven were tested not only in their nominal mode but also during overclocking:
PerformanceGeneral PerformanceTheresults in the complex SYSmark 2007 test turned out not quiteoptimistic. Overall, even though Phenom II X4 920 outperforms itsdirect rivals in nominal mode, overclocking changes this picture. EvenCore 2 Quad Q8300 processor overclocked to 3.57 GHz outperforms PhenomII X4 920 working at 3.72 GHz. On the one hand, it once again indicatesthat Intel processors boast better IPC (instructions per clock), but onthe other – shows that Intel CPUs boast higher frequency potential,even though it is not fully revealed. While Phenom II X4 920overclocked by 33%, Core 2 Quad Q8300 reached 43% higher frequency whenit was stopped by the mainboard’s inability to catch up.
However,things are a little different in certain type of applications. Forexample, overclocked Phenom II X4 920 processor is a little ahead ofCore 2 Quad Q8300 in E-Learning scenario working with vector and rasterimages, PowerPoint presentations, PDF-files and flash-videos. And italmost catches up with the overclocked Core 2 Quad Q9300 inProductivity scenario that works with Microsoft Office suite.
Gaming PerformanceAtfirst glance, the new AMD solution seems to be winning in 3D games.Phenom II X4 920 working at 3.72 GHz outperforms its major Core 2 QuadQ8300 competitor in every single test we used. However, it most likelyhappens due to seriously cut-down cache-memory of the Intel CPU. Thatis why when we compare the performance of our Phenom II X4 920 againstthat of an overclocked Core 2 Quad Q6600, the outcome is no longer inAMD’s favor: even though Q6600 processor belongs to the previousgeneration, it features an 8MB L2 cache.
Overall, we are notreally talking about any serious performance differences. OverclockedPhenom II X4 looks quite well and demonstrates very good performance.Nevertheless, I have to say that overclocking a $200 quad-coreprocessor will not provide the users with the same performance thatthey could get from higher-end more expensive CPUs, even working attheir nominal speeds.
Video EncodingVideoencoding is the best application for the new AMD processors. Phenom IIX4 920 outperforms its rivals in nominal mode as well as duringoverclocking. By the way, at 3.72 GHz it also outperforms Core 2 QuadQ6600. However, it is still very far behind the impressive resultsdemonstrated by Core i7 CPUs. No wonder, since SMT technologyimplemented in the latest Intel solutions matters here a lot.
RenderingItis pretty hard to put together a single verdict at this type ofworkload. As you can clearly see from the diagrams, everything dependson the rendering application. Nevertheless, we can’t help stressing theimpressive results of Core i7 CPUs: they are evidently the best choicein easily paralleled computational tasks. No doubt about that.
Other ApplicationsFritzand Folding@Home are another two examples where “pure” computationspower of the CPU is important. So processors with higher IPC win inthese tests, and Phenom II X4 920 is evidently not one of them.Overclocking Phenom II X4 920 doesn’t help here either. The onlyconsolation is outperforming a much more expensive Core 2 Quad Q9650.
Thesituation in Photoshop is also not the best for Phenom II X4 920. Withor without overclocking, it yields to its main rival – Core 2 QuadQ8300.
However,the results of the WinRAR test will be a real pleaser for AMD fans. Thenew AMD CPU as always scores very high in this application.
Power ConsumptionOur Phenom II X4 920 performance testsshowed that it may be a very good choice for an overclocker platform.But before we draw any final conclusions, let’s see if it turns out aspower-efficient as Intel CPUs. So, we measured the power consumption ofa system (without the monitor) built around AMD Phenom II X4 920 in itsnominal mode and during overclocking and compared these resultsagainst similar platforms built with Intel CPUs from the same pricerange, namely, Core 2 Quad Q8300, Core 2 Quad Q9300 and Core 2 QuadQ6600.
During this test session we loaded the CPUs using Prime95utility. Besides, we activated all power-saving technologies, such asC1E, Cool’n’Quiet and Enhanced Intel SpeedStep, to make sure that thepower readings in idle mode were correct. It is important to rememberthat Enhanced Intel SpeedStep is implemented in such a way that duringoverclocking it doesn’t change the processor core voltage, but stilllowers their frequency under low workload. AMD Cool’n’Quiet technology,however, is fully operational even in an overclocked system.
| | Idle | 100% Load | Phenom II X4 920
| 144 W | 219 W | Core 2 Quad Q6600
| 157 W | 246 W | Core 2 Quad Q8300
| 135 W | 189 W | Core 2 Quad Q9300
| 136 W | 192 W |
| Phenom II X4 920 @ 3.72GHz
| 153 W | 312 W | Core 2 Quad Q6600 @ 3.6GHz
| 212 W | 318 W | Core 2 Quad Q8300 @ 3.56GHz
| 141 W | 236 W | Core 2 Quad Q9300 @ 3.56GHz
| 142 W | 241 W |
Unfortunately,new AMD processors still lose to alternatives from Intel even thoughthey are now manufactured with more advanced 45nm process. Even innominal mode a system on Phenom II X4 920 processor consumes 20-30 Wmore than similarly performing platforms on Intel CPUs. In fact,power-efficiency of the new Phenom II X4 processors improved onlycompared to the previous-generation quad-core Intel processorsmanufactured with 65nm process that are still widely available inretail.
During overclocking, the situation is not any better forAMD offering. Although Phenom II X4 920 boasts fully operationalCool’n’Quiet technology in overclocked mode, even in idle mode thesystem built on it consumes more power than Core 2 Quad Q8300 and Q9300based platforms. When the CPU utilization hits 100%, the powerconsumption difference turns more than serious and reaches 70-80 W.Moreover, power consumption of an overclocked Phenom II X4 920 basedsystem is almost the same as that of Core 2 Quad Q6600 (3.6 GHz) basedsystem.
However, there is a very logical explanation why the newAMD CPU didn’t impress us with its power consumption readings duringoverclocking. Even though Phenom II X4 processors use 45nm cores, theyrequire much higher Vcore than Intel processors.
ConclusionPhenom II X4 processors didn’t bring the desktopperformance to any revolutionary heights. Unfortunately, even newmanufacturing process doesn’t let AMD design CPUs that couldsuccessfully compete against Intel solutions in all price segments. Andalthough the clock frequencies of the new AMD processors increasedsignificantly, their performance turned out limited by the Stars (K10)microarchitecture potential, because it boasts lower IPC than thecurrent Intel microarchitecture. Phenom II X4 920 we have justdiscussed is a great illustration to everything we have just said. Atits nominal 2.8 GHz it can only compete against Core 2 Quad running at2.4 – 2.5 GHz frequencies. Only smart pricing strategy helps AMD here:they positioned Phenom II X4 920 in such a way that it turns out alittle better than the identically priced Core 2 Quad models.
However,overclockers have their own perception of the situation. They areprimarily interested in the processor’s ability to work in modes otherthan nominal. And here the new Phenom II X4 appeared much moreattractive than their predecessors. We could easily overclock ourPhenom II X4 920 processor by 33% clock frequency without anysophisticated cooling involved. At this frequency our CPU was onaverage faster than an overclocked Core 2 Quad Q8300. This resultcertainly makes quad-core Phenom II X4 920 a good overclocking choicein the sub-$200 price range.
However, you shouldn’t overestimatethe overclocking potential of Phenom II X4 920 processor, because Core2 Quad Q8300 is far not the strongest competitor in the Intel camp. Forinstance, the similarly priced Core 2 Quad Q6600 can hit much higherfrequencies than Core 2 Quad Q8300, even though it belongs to theprevious generation. So this processor can be on average faster thanPhenom II X4 920 working at a higher frequency, too.
Anotherweakness of the new Phenom II X4 920 processor, which stands out moreduring overclocking especially, is high power consumption. According toour tests, at 3.72 GHz it falls far behind more power-efficient Intelprocessors from Q8000 and Q9000 series. In fact, it almost catches upwith Core 2 Quad Q6600 here.
Nevertheless, we are extremelypleased with the results demonstrated by Phenom II X4 920. Although itdidn’t outperform the similarly priced Core 2 Quad dramatically, wecan’t say that it yields a lot to its rival, either. And it means thatAMD has every chance to become quite popular among overclocking fansdue to their new 45nm processors. |
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发表于 3-5-2009 08:45:20
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