Intel P35 Memory Performance: A Closer Look
by Wesley Fink on May 18, 2007 12:00 PM EST- Posted in
- CPUs
Bandwidth and Memory Scaling
The results chart was greatly expanded for these benchmarks. Instead of grouping together similar timings for easier comparison we have listed every timing used for DDR3 and DDR2 benchmarking. The bold values are the best performing results for that memory speed. We did take a bit of liberty here since the 800 5-6-6 and 6-6-6 timings are considered together, as are the 1066 5-6-6, 6-6-6, and 7-7-7 timings. If that is too broad a consideration for your liking the data is here for you to interpret how you see fit.
The percentages in parentheses after the upper values compare that result to the performance of the equivalent setting on the P965 ASUS P5B Deluxe. This is compared on P965, P35 DDR2, and P35 DDR3 at 1066FSB. As explained on the previous page, 1333 memory speed could not be tested at 1066 CPU FSB which is why that result is missing from the 1066 FSB list.
Results are also present for the P35 boards at 1333 processor bus at the same CPU speed (both at 2.66 GHz as detailed). Again, the limitations of the P965 did not allow us to run comparable 1333 FSB results since the memory ratios are not available for a 1333 FSB CPU.
The 10x266 results are roughly representative of the improvement in memory bandwidth that can be attributed to the memory controller of the P35. Considering the variables in timing, this ranges from around 3% to 6.5%. Since the DDR-800 results are the most comparable across all the memory types, and that ranges from 4.7% to 6.5% improved bandwidth, we would conclude that the contribution of the P35 memory controller to improved memory bandwidth is roughly +5%.
The 2.66GHz 8x333 results show the total impact of the improved P35 memory controller and the increase in processor bus to 1333. As you can see the total improvement in memory bandwidth is 16% to 18%. This means the increase in processor bus speed to 1333 is contributing about 11% to 13% to the bandwidth increase, since we concluded the impact of the memory controller alone to be about 5%.
Those of you who are now saying, "Just as I suspected, it's just the 1333 processor bus that is boosting performance" may want to reserve judgment until the game tests. You will likely be surprised.
We normally also test memory with buffering schemes like MMX, SSE, SSE2, SSE3, etc, turned off. While these features do provide apparent improved bandwidth, we have found the unbuffered bandwidth to correlate better with real-world application performance. Unbuffered performance does not always follow the patterns of buffered memory performance.
The expanded unbuffered results are somewhat different than the unbuffered results in our earlier review. The memory controller contributes from 2% to 8.7% of the memory bandwidth improvement. With our target of the DDR-800 results as most comparable the contribution to improved unbuffered bandwidth is 5%, which is about the same as the buffered contribution. This is pretty unusual, since as you can see below the 1333 line, unbuffered bandwidth improvement is 4% to about 12%, which is lower than the buffered total improvement. For buffered memory bandwidth the memory controller is contributing about 5% of the improvement and the increased processor bus is adding 0% to 6%. Since unbuffered results normally correlate well with gaming performance this hints at the somewhat unexpected gaming results.
The results chart was greatly expanded for these benchmarks. Instead of grouping together similar timings for easier comparison we have listed every timing used for DDR3 and DDR2 benchmarking. The bold values are the best performing results for that memory speed. We did take a bit of liberty here since the 800 5-6-6 and 6-6-6 timings are considered together, as are the 1066 5-6-6, 6-6-6, and 7-7-7 timings. If that is too broad a consideration for your liking the data is here for you to interpret how you see fit.
The percentages in parentheses after the upper values compare that result to the performance of the equivalent setting on the P965 ASUS P5B Deluxe. This is compared on P965, P35 DDR2, and P35 DDR3 at 1066FSB. As explained on the previous page, 1333 memory speed could not be tested at 1066 CPU FSB which is why that result is missing from the 1066 FSB list.
Results are also present for the P35 boards at 1333 processor bus at the same CPU speed (both at 2.66 GHz as detailed). Again, the limitations of the P965 did not allow us to run comparable 1333 FSB results since the memory ratios are not available for a 1333 FSB CPU.
| Standard (Buffered) Sandra XI.SP2 Memory Bandwidth - 2.66GHz | |||
| Memory Speed | P965 ASUS P5B Dlx |
P35 DDR2 ASUS P5K Dlx |
P35 DDR3 ASUS P5K3 Dlx |
| 10 x 266 - 1066FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | 5531 | 5754 (+4.0%) |
- |
| DDR2-800 5-6-6-15 | 5207 | - | - |
| DDR2-800 6-6-6-15 | - | 5545 (+6.5%) |
- |
| DDR3-800 6-6-6-15 | - | - | 5451 (+4.7%) |
| DDR2-1067 4-4-3-11 | 5782 | 6037 (+4.4%) |
- |
| DDR2-1067 5-6-6-15 | 5712 | - | - |
| DDR2-1067 6-6-6-15 | - | 5872 (+2.8%) |
- |
| DDR3-1067 7-7-7-20 | - | - | 5843 (+2.3%) |
| 8x333 - 1333FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | - | 6456 (+16.7%) |
- |
| DDR2-800 6-6-6-15 | - | 6143 (+18.0%) |
- |
| DDR3-800 6-6-6-15 | - | - | 6156 (+18.2%) |
| DDR2-1067 4-4-3-11 | - | 6811 (+17.8%) |
- |
| DDR2-1067 6-6-6-15 | - | 6621 (+15.9%) |
- |
| DDR3-1067 7-7-7-20 | - | - | 6613 (+15.8%) |
| DDR3-1333 9-9-9-25 | - | - | 6757 |
The 10x266 results are roughly representative of the improvement in memory bandwidth that can be attributed to the memory controller of the P35. Considering the variables in timing, this ranges from around 3% to 6.5%. Since the DDR-800 results are the most comparable across all the memory types, and that ranges from 4.7% to 6.5% improved bandwidth, we would conclude that the contribution of the P35 memory controller to improved memory bandwidth is roughly +5%.
The 2.66GHz 8x333 results show the total impact of the improved P35 memory controller and the increase in processor bus to 1333. As you can see the total improvement in memory bandwidth is 16% to 18%. This means the increase in processor bus speed to 1333 is contributing about 11% to 13% to the bandwidth increase, since we concluded the impact of the memory controller alone to be about 5%.
Those of you who are now saying, "Just as I suspected, it's just the 1333 processor bus that is boosting performance" may want to reserve judgment until the game tests. You will likely be surprised.
We normally also test memory with buffering schemes like MMX, SSE, SSE2, SSE3, etc, turned off. While these features do provide apparent improved bandwidth, we have found the unbuffered bandwidth to correlate better with real-world application performance. Unbuffered performance does not always follow the patterns of buffered memory performance.
| Unbuffered Sandra XI.SP2 Memory Bandwidth - 2.66GHz | |||
| 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 | 4226 | 4370 (+3.4%) |
- |
| DDR2-800 5-6-6-15 | 3668 | - | |
| DDR2-800 6-6-6-15 | - | 3853 (+5.0%) |
- |
| DDR3-800 6-6-6-15 | - | - | 3988 (+8.7%) |
| DDR2-1067 4-4-3-11 | 4608 | 4706 (+2.1%) |
- |
| DDR2-1067 5-6-6-15 | 4389 | - | - |
| DDR2-1067 6-6-6-15 | - | 4484 (+2.2%) |
|
| DDR3-1067 7-7-7-20 | - | - | 4311 -1.8%) |
| 8x333 - 1333 FSB - 2.66GHz | |||
| DDR2-800 3-3-3-9 | - | 4536 (+7.3%) |
- |
| DDR2-800 6-6-6-15 | - | 3975 (+8.4%) |
- |
| DDR3-800 6-6-6-15 | - | - | 4098 (+11.7%) |
| DDR2-1067 4-4-3-11 | - | 4926 (+6.9%) |
- |
| DDR2-1067 6-6-6-15 | - | 4557 (+3.8%) |
- |
| DDR3-1067 7-7-7-20 | - | - | 4547 (+3.6%) |
| DDR3-1333 9-9-9-25 | - | - | 4702 |
The expanded unbuffered results are somewhat different than the unbuffered results in our earlier review. The memory controller contributes from 2% to 8.7% of the memory bandwidth improvement. With our target of the DDR-800 results as most comparable the contribution to improved unbuffered bandwidth is 5%, which is about the same as the buffered contribution. This is pretty unusual, since as you can see below the 1333 line, unbuffered bandwidth improvement is 4% to about 12%, which is lower than the buffered total improvement. For buffered memory bandwidth the memory controller is contributing about 5% of the improvement and the increased processor bus is adding 0% to 6%. Since unbuffered results normally correlate well with gaming performance this hints at the somewhat unexpected gaming results.
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JarredWalton - Friday, May 18, 2007 - link
We don't generally used beta drivers unless there is no other viable option (i.e. a new graphics card where the non-beta drivers are not yet available). I don't really expect the later drivers to improve performance, but perhaps that's something Gary will be looking at in our official P35 chipset article. Check back next week. :-)rjm55 - Friday, May 18, 2007 - link
I was fairly convinced that the increases you saw the first time were just the 1333 speed. Looks like I was wrong. Thanks for doing more testing that shows the P35 is a better performer and the reasons are the memory controller by itself in gaming. This should shut up the no-difference posters.sdsdv10 - Friday, May 18, 2007 - link
Agreed. Article like this is why AnandTech is one of best tech sites on the web!sdsdv10 - Friday, May 18, 2007 - link
Ummm...Article --> Articles
While they maybe one the best, the comment section could still use a edit function dammit.