Intel P35 Memory Performance: A Closer Look
by Wesley Fink on May 18, 2007 12:00 PM EST- Posted in
- CPUs
Number Crunching and Gaming
The only real improvement in our tests is a 16% to 18% improvement in memory bandwidth on P35, whether it is running DDR2 or DDR3. Does the memory bandwidth improvement translate into any real improvement in system performance? Where there are performance improvements are they likely attributable to the improved memory controller or the faster CPU bus?
SuperPi 1.5 at a 2M setting was run in all memory and speed configurations. This utility benchmarks system performance in pure number crunching as it calculates pi to the number of decimal points selected (in this case 2 million). SuperPi is a very simple program but due to the size of the data set memory performance is often a critical factor.
With all tests run with the same X6800 CPU at 10x266 and 8x333 processor speeds, there was no clear performance improvement in SuperPi. It is interesting that most of the best (lowest) SuperPi results were with the P35 at 1066 processor bus. In most cases SuperPi performed better at 10x266 2.66 than at 8x333 2.66 which was something of a surprise. SuperPi performance is a very slightly better as a result of the P35 controller. The 1333 performance is still a bit faster than the P965, but the faster processor bus seems to actually degrade SuperPi performance a tiny amount.
Gaming
A standardized game benchmark was chosen from our memory test suite to determine if the better P35 memory bandwidth improved gaming performance. The Far Cry - River demo was run for 3 loops and results in fps were averaged over the 3 runs. This benchmark was chosen because we are familiar with how it behaves in memory performance tests. A full suite of gaming tests will be run in the P35 performance launch on May 21st.
Using the same CPU for all tests actually shows greater improvements in gaming performance than was seen in the DDR3 vs. DDR2 review. As you can see in the comparisons above the P35 memory controller contributed 3 to 5% improvement in gaming performance. Our target DDR-800 results showed a 4.6% to 5.2% improvement, so we conclude the P35 memory controller improves gaming performance roughly 5%
Results below the 1333 line represent total improvement, which varied from about 4% to 6%. With the target DDR-800 performance improvement ranging from 5.4% to 5.7% total, and the memory controller alone contributing 5% improvement, we are left with about 0.5% performance improvement in gaming due to the higher processor bus.
These results were a bit of a surprise. Almost all of the improvement in real-world gaming came as a result of the improved P35 memory controller, with about half a percent attributable to the 1333 processor bus. The Far Cry benchmarks show most of the real world gaming improvements are the result of the P35 memory controller.
The only real improvement in our tests is a 16% to 18% improvement in memory bandwidth on P35, whether it is running DDR2 or DDR3. Does the memory bandwidth improvement translate into any real improvement in system performance? Where there are performance improvements are they likely attributable to the improved memory controller or the faster CPU bus?
SuperPi 1.5 at a 2M setting was run in all memory and speed configurations. This utility benchmarks system performance in pure number crunching as it calculates pi to the number of decimal points selected (in this case 2 million). SuperPi is a very simple program but due to the size of the data set memory performance is often a critical factor.
| Super Pi 1.5 - 2.66GHz Time in Seconds - Lower is Better |
|||
| Memory Speed | P965 ASUS P5B Dlx |
P35 DDR2 ASUS P5K Dlx |
P35 DDR3 ASUS P5K3 Dlx |
| 10 x 266 - 1066 FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | 46.05 | 45.59 (-1.0%) |
- |
| DDR2-800 5-6-6-15 | 47.28 | - | |
| DDR2-800 6-6-6-15 | - | 46.77 (-1.1%) |
- |
| DDR3-800 6-6-6-15 | - | - | 46.95 (-0.7%) |
| DDR2-1067 4-4-3-11 | 45.39 | 45.03 (-0.8%) |
- |
| DDR2-1067 5-6-6-15 | 45.72 | - | - |
| DDR2-1067 6-6-6-15 | - | 45.16 (-1.2%) |
|
| DDR3-1067 7-7-7-20 | - | - | 46.03 (+0.7%) |
| 8x333 - 1333 FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | - | 45.78 (-0.6%) |
- |
| DDR2-800 6-6-6-15 | - | 46.08 (-2.5%) |
- |
| DDR3-800 6-6-6-15 | - | - | 46.89 (-0.8%) |
| DDR2-1067 4-4-3-11 | - | 45.20 (-0.4%) |
- |
| DDR2-1067 6-6-6-15 | - | 45.81 (-0.2%) |
- |
| DDR3-1067 7-7-7-20 | - | - | 45.93 (-0.5%) |
| DDR3-1333 9-9-9-25 | - | - | 45.77 |
With all tests run with the same X6800 CPU at 10x266 and 8x333 processor speeds, there was no clear performance improvement in SuperPi. It is interesting that most of the best (lowest) SuperPi results were with the P35 at 1066 processor bus. In most cases SuperPi performed better at 10x266 2.66 than at 8x333 2.66 which was something of a surprise. SuperPi performance is a very slightly better as a result of the P35 controller. The 1333 performance is still a bit faster than the P965, but the faster processor bus seems to actually degrade SuperPi performance a tiny amount.
Gaming
A standardized game benchmark was chosen from our memory test suite to determine if the better P35 memory bandwidth improved gaming performance. The Far Cry - River demo was run for 3 loops and results in fps were averaged over the 3 runs. This benchmark was chosen because we are familiar with how it behaves in memory performance tests. A full suite of gaming tests will be run in the P35 performance launch on May 21st.
| Far Cry - HOC River Time in Frames Per Second - Higher is Better |
|||
| Memory Speed | P965 ASUS P5B Dlx |
P35 DDR2 ASUS P5K Dlx |
P35 DDR3 ASUS P5K3 Dlx |
| 10 x 266 - 1066 FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | 101.26 | 106.01 (+4.7%) |
- |
| DDR2-800 5-6-6-15 | 97.76 | - | |
| DDR2-800 6-6-6-15 | - | 102.80 (+5.2%) |
- |
| DDR3-800 6-6-6-15 | - | - | 102.29 (+4.6%) |
| DDR2-1067 4-4-3-11 | 103.04 | 107.65 (+4.5%) |
- |
| DDR2-1067 5-6-6-15 | 102 | - | - |
| DDR2-1067 6-6-6-15 | - | 106.06 (+4.0%) |
|
| DDR3-1067 7-7-7-20 | - | - | 104.62 (2.6%) |
| 8x333 - 1333 FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | - | 106.30 (+5.0%) |
- |
| DDR2-800 6-6-6-15 | - | 103.01 (+5.4%) |
- |
| DDR3-800 6-6-6-15 | - | - | 103.39 (+5.7%) |
| DDR2-1067 4-4-3-11 | - | 108.00 (+4.8%) |
- |
| DDR2-1067 6-6-6-15 | - | 106.61 (+4.5%) |
- |
| DDR3-1067 7-7-7-20 | - | - | 105.87 (+3.8%) |
| DDR3-1333 9-9-9-25 | - | - | 106.7 |
Using the same CPU for all tests actually shows greater improvements in gaming performance than was seen in the DDR3 vs. DDR2 review. As you can see in the comparisons above the P35 memory controller contributed 3 to 5% improvement in gaming performance. Our target DDR-800 results showed a 4.6% to 5.2% improvement, so we conclude the P35 memory controller improves gaming performance roughly 5%
Results below the 1333 line represent total improvement, which varied from about 4% to 6%. With the target DDR-800 performance improvement ranging from 5.4% to 5.7% total, and the memory controller alone contributing 5% improvement, we are left with about 0.5% performance improvement in gaming due to the higher processor bus.
These results were a bit of a surprise. Almost all of the improvement in real-world gaming came as a result of the improved P35 memory controller, with about half a percent attributable to the 1333 processor bus. The Far Cry benchmarks show most of the real world gaming improvements are the result of the P35 memory controller.
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TA152H - Friday, May 18, 2007 - link
I've looked over these numbers a few times, and tried to make some sense of it, and the remarks about the x6800 being slower on SuperPi, but faster on other things.There were a few clear patterns, which SuperPi managed to break, which leads me to a conclusion that this benchmark needs to be looked at closer.
For example, I noticed that DDR3 shows a greater advantage at the 1333 FSB setting, and starts leaving DDR2 behind. Except on SuperPi.
In every benchmark, 1333 FSB is faster. Except in SuperPi.
The x6800 is faster than other processors on benchmarks at the same settings, except on SuperPi.
Ummmm, anyone else think that there might be something amuck with SuperPi and it probably should be looked at more closely and possibly be removed as a benchmark until it is KNOWN to work correctly. It seems completely wrong. However, if it is reporting correctly, it would be very informative to know why it runs exactly opposite everything else. Is it using the processor in an unusual way? If so, what other applications do, so people know when to pay attention to it, and when not to.
I think the most interesting thing is how the DDR3 likes the 1333 FSB a lot more than DDR2 does. It's clearly the memory of the future.
noobzter - Friday, May 18, 2007 - link
Wes, could you elaborate on that? I've always wondered whether there's any difference between running C2Ds at higher multiplier and higher FSB (e.g. 13x267 vs 10x347)
Wesley Fink - Friday, May 18, 2007 - link
Several editors have noticed that the X6800 at the exact same speed and timing settings is a bit faster in gaming performance and a bit slower in Super Pi performance compared to other C2D processors. This is somewhat contradictory, but .We really don't know why this is the case, but we have seen it over a number of boards and in quite a few test configurations. While we don't know exactly what is different about the X6800 Extreme to make it perform this way, we do know the X6800 Extreme behaves a littel differently in benchmarks. We've asked Intel, but we have never received an answer that explained these minor differences to us.
IntelUser2000 - Friday, May 18, 2007 - link
I can explain that. When Core microarchitecture based CPUs first came out, Intel talked about being able to optimize the prefetchers for the target segment. Mobile chips would have less aggressive and power optimized prefetchers, Desktop chips would be performance optimized(relative to the mobile) and the Xeon variants would be fit for the server/workstation workloads. I would assume the "X" chips could be optimized for gaming, and that may explain the difference.
How much faster is it btw??
Wesley Fink - Saturday, May 19, 2007 - link
If you compare the 1333 gaming numbers from the ddr3 vs. ddr2 review to those in this review you will see the exact difference at the various settings. The ddr3 vs. ddr2 were run with an E6420 at 8x333, while this review used the X6800 at 8x333.Deusfaux - Friday, May 18, 2007 - link
I would guess it would have to do something with cherry picking those particular cores in the fab process and thus getting you the procs from the top of the heap that are just a wee bit better at everything and why they can also justify selling it for such a markup.yacoub - Friday, May 18, 2007 - link
I'd love to know how much performance can be gained on 650i-SLI board going from 10x266 to 8x333. I currently run 10x266 E4400 @ 2.67GHz. I wonder if I'd gain any performance running it at 8x333 and if it'd be worth the added stress to the motherboard to run at 1333MHz fsb. It's an MSi P6N-SLI Platinum.yacoub - Friday, May 18, 2007 - link
Also do I leave my PC6400 DDR2 RAM at 800MHz default or raise it a bit (they don't do 1066 very well), but I could lower them to 667MHz if for some reason it was more ideal to run a 1:2 multiplier from the 333MHz fsb than leaving them up at 800MHz.vailr - Friday, May 18, 2007 - link
Why don't you use the latest beta version Intel chipset drivers?[Instead of: System Platform Drivers Intel - 8.3.0.1013]
Version 8.4.0.1010 Beta:
http://www.station-drivers.com/telechargement/inte...">http://www.station-drivers.com/telechargement/inte...
Wesley Fink - Friday, May 18, 2007 - link
Intel tells us there are no performance imnprovements in the beta drivers. The beta drivers fix a few compatibility issues with Vista. We prefer to use release drivers unless there is a compelling performance or new release reason to use beta drivers. Gary is not testing with the new beta drivers either.