Intel P35 Memory Performance: A Closer Look
by Wesley Fink on May 18, 2007 12:00 PM EST- Posted in
- CPUs
Final Words
Many readers raised the valid concerns of whether the improvement in Bearlake (P35) memory performance was the result of the improved memory controller or whether it was merely a side effect of the faster 1333 processor bus. We tried to answer this in comments to the original review, but the question deserved additional testing to clearly show where the performance improvements are originating.
In the area of memory bandwidth improvement, it appears that the memory controller is roughly adding about 5% to P965 performance while the faster 1333 processor bus contributes an additional 11% to 13%. The total improvement in memory bandwidth for P35 compared to the P965 is 16% to 18%. Memory is just one small part of overall system performance, so this does not translate into a 16% improvement in system performance. System performance is improved, but real-world performance improvements are smaller.
In pure number crunching it appears that the P35 only slightly improves performance, in the 0.5% to 2.5% range. It is interesting that almost all of the SuperPi improved performance is a result of the improved P35 memory controller, since the higher 1333 processor bus actually decreases performance a very small amount compared to the 1066 bus.
Gaming performance with Far Cry benchmarks was found to improve 3% to 6% on the P35. About 5% of that increase was due to the improved P35 memory controller, with the higher 1333 bus only adding about 0.5% to the performance.
The memory performance improvements for P35, as stated in the initial review, are pretty impressive for just a chipset upgrade. The memory bandwidth improves 16% to 18%, with about 5% of that increase due to an improved memory controller. The rest is the result of the higher 1333 processor bus. SuperPi performance improves slightly - 0.5% to 2.5% - almost all due to the improved P35 memory controller and gaming performance improves about 5.5%, again almost entirely the result of the improved memory controller.
With this closer look at the components of the P35 improvements in memory performance, we can put to rest the either/or vein of questions about the increase in processor bus. The improvement in P35 memory performance is a result of a combination of an improved memory controller and a faster processor bus. It is not the result of either factor alone. In some cases, like memory bandwidth, the processor bus is the larger contributor. In others, like gaming, the improved memory controller is the bigger factor.
Regardless of which aspect improves memory performance the most, however, it is clear the P35 is a better performing chipset than the earlier P965. If you are in the market for a new system, the P35 is a good chipset for building a performance system. This is particularly true if you intend to use a 1066 FSB processor with the "free" 25% overclock that is possible by just setting 1333 instead of 1066 in the motherboard BIOS.
Many readers raised the valid concerns of whether the improvement in Bearlake (P35) memory performance was the result of the improved memory controller or whether it was merely a side effect of the faster 1333 processor bus. We tried to answer this in comments to the original review, but the question deserved additional testing to clearly show where the performance improvements are originating.
In the area of memory bandwidth improvement, it appears that the memory controller is roughly adding about 5% to P965 performance while the faster 1333 processor bus contributes an additional 11% to 13%. The total improvement in memory bandwidth for P35 compared to the P965 is 16% to 18%. Memory is just one small part of overall system performance, so this does not translate into a 16% improvement in system performance. System performance is improved, but real-world performance improvements are smaller.
In pure number crunching it appears that the P35 only slightly improves performance, in the 0.5% to 2.5% range. It is interesting that almost all of the SuperPi improved performance is a result of the improved P35 memory controller, since the higher 1333 processor bus actually decreases performance a very small amount compared to the 1066 bus.
Gaming performance with Far Cry benchmarks was found to improve 3% to 6% on the P35. About 5% of that increase was due to the improved P35 memory controller, with the higher 1333 bus only adding about 0.5% to the performance.
The memory performance improvements for P35, as stated in the initial review, are pretty impressive for just a chipset upgrade. The memory bandwidth improves 16% to 18%, with about 5% of that increase due to an improved memory controller. The rest is the result of the higher 1333 processor bus. SuperPi performance improves slightly - 0.5% to 2.5% - almost all due to the improved P35 memory controller and gaming performance improves about 5.5%, again almost entirely the result of the improved memory controller.
With this closer look at the components of the P35 improvements in memory performance, we can put to rest the either/or vein of questions about the increase in processor bus. The improvement in P35 memory performance is a result of a combination of an improved memory controller and a faster processor bus. It is not the result of either factor alone. In some cases, like memory bandwidth, the processor bus is the larger contributor. In others, like gaming, the improved memory controller is the bigger factor.
Regardless of which aspect improves memory performance the most, however, it is clear the P35 is a better performing chipset than the earlier P965. If you are in the market for a new system, the P35 is a good chipset for building a performance system. This is particularly true if you intend to use a 1066 FSB processor with the "free" 25% overclock that is possible by just setting 1333 instead of 1066 in the motherboard BIOS.
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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.