Intel's Core 2 Extreme QX6700: The Multi-core Era Begins
by Anand Lal Shimpi on November 2, 2006 2:14 AM EST- Posted in
- CPUs
Performance per Watt Comparison
3dsmax 7
3dsmax, like many 3D renderers, absolutely loves more cores and here we see Kentsfield maintain a tremendous performance advantage over Conroe. The scores reported are the SPECapc 3dsmax rendering composite in points, higher numbers being better, but the most interesting values are the performance per watt numbers.
Note: we are looking at system power draw rather than trying to isolate just the CPU. In that sense, we are comparing potential of running quad core configurations - i.e. in render farms and the like - instead of more dual core systems. Were we to get just the CPU power usage numbers, we would expect the usage of two identical cores in a single package to basically double power draw.
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 4.11 pts | 192.5W | 0.0214 pts/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 6.59 pts | 230.5W | 0.0286 pts/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 3.77 pts | 189.2W | 0.0199 pts/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 5.96 pts | 225.9W | 0.0264 pts/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 3.39 pts | 184.4W | 0.0184 pts/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 2.68 pts | 176.1W | 0.0152 pts/W |
| Intel Core 2 Single Core (2.40GHz) | 1.85 pts | 174.1W | 0.0106 pts/W |
With higher performance and higher power consumption, the two manage to balance out and result in better performance per watt out of the two Kentsfield based parts than any of the dual core CPUs. While Kentsfield does require more power than Conroe, you get an even larger increase in performance thus resulting in a more efficient overall CPU.
Let's see if this is the start of a trend...
Cinebench 9.5
The Cinebench 9.5 test is also a multithreaded 3D rendering benchmark that will take advantage of as many cores as are present in the system. For each core, Cinebench spawns an additional renderer to help speed up the rendering of a static scene. Performance goes up by over 60% when moving from two to four cores, but once again it's the performance per watt that is particularly interesting:
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 892 pts | 189W | 4.719 pts/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 1337 pts | 225.1W | 5.939 pts/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 816 pts | 186.1W | 4.384 pts/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 1216 pts | 219.8W | 5.532 pts/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 751 pts | 181.8W | 3.973 pts/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 582 pts | 175.4W | 3.127 pts/W |
| Intel Core 2 Single Core (2.40GHz) | 402 pts | 172.2W | 2.334 pts/W |
None of the dual core CPUs can come close to touching the power efficiency of the quad core Kentsfield based offerings.
DivX 6.1
Media encoding applications were the first to get a performance boost from dual core CPUs, but the impact is not nearly as great when we move to quad core processors. There's a gain of around 38%, which is by no means bad, just simply not as great as what we saw in the previous 3D rendering tests. The end result is that performance per watt is a lot closer between the most efficient dual core CPUs and the new quad core offerings:
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 19.4 fps | 189.2W | 0.1027 fps/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 24.8 fps | 223.7W | 0.1108 fps/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 18.0 fps | 185.7W | 0.0968 fps/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 24.0 fps | 220.0W | 0.1089 fps/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 16.3 fps | 183.0W | 0.0864 fps/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 13.8 fps | 176.9W | 0.0745 fps/W |
| Intel Core 2 Single Core (2.40GHz) | 11.2 fps | 170.7W | 0.0658 fps/W |
If we look at performance per watt per transistor, Kentsfield is really not doing well here at all, despite an increase in performance and a continued advantage in performance per watt.
Windows Media Encoder 9
We see a much stronger showing from Kentsfield in the WME9 test, indicating that the DivX test was not representative of all media encoding on quad core.
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 61.5 fps | 189.1W | 0.3252 fps/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 86.4 fps | 223.2W | 0.3870 fps/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 55.8 fps | 184.5W | 0.3025 fps/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 78.9 fps | 218.6W | 0.3608 fps/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 50.4 fps | 181.8W | 0.2665 fps/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 39.4 fps | 176.9W | 0.2137 fps/W |
| Intel Core 2 Single Core (2.40GHz) | 31.3 fps | 171.7W | 0.1822 fps/W |
Quicktime (H.264)
Interestingly enough, our Quicktime H.264 test didn't show any performance improvement going from two to four cores, indicating that the encoding process is optimized for two threads. Quicktime thus becomes the posterchild for what's necessary for the multicore revolution to truly bring about greater power efficiency: better threading within applications.
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 30.0 fps | 191.2W | 0.1569 fps/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 27.5 fps | 210.0W | 0.1309 fps/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 27.5 fps | 188.1W | 0.1461 fps/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 25.2 fps | 207.0W | 0.1216 fps/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 26.5 fps | 185.1W | 0.1430 fps/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 19.8 fps | 177.7W | 0.1113 fps/W |
| Intel Core 2 Single Core (2.40GHz) | 16.2 fps | 170.6W | 0.0951 fps/W |
Here the dual core offerings are clearly superior when it comes to performance per watt simply because the Kentsfield CPUs aren't able to outperform them, all while using more power. The efficiency wouldn't be a problem if Kentsfield was able to power down unused cores independently of one another.
iTunes MP3
Our final test is yet another benchmark that only spawns two encoding threads, and we get another example of how power efficiency falls off if the software is not threaded enough to match the CPU's resources.
| CPU | Performance |
Average Power Consumption | Performance per Watt |
| Intel Core 2 Extreme X6800 (2.93GHz) | 11.7 MB/s | 193.4W | 0.0605 MBps/W |
| Intel Core 2 Extreme QX6700 (2.66GHz) | 10.9 MB/s | 213.1W | 0.0509 MBps/W |
| Intel Core 2 Duo E6700 (2.66GHz) | 10.5 MB/s | 188.3W | 0.0557 MBps/W |
| Intel Core 2 Quad Q6600 (2.40GHz) | 9.8 MB/s | 206.8W | 0.0474 MBps/W |
| Intel Core 2 Duo E6600 (2.40GHz) | 9.8 MB/s | 185.4W | 0.0529 MBps/W |
| Intel Core 2 Duo E6300 (1.86GHz) | 7.6 MB/s | 177.0W | 0.0429 MBps/W |
| Intel Core 2 Single Core (2.40GHz) | 6.1 MB/s | 168.4W | 0.0361 MBps/W |
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archcommus - Thursday, November 2, 2006 - link
Quote form the conclusion page:"We don't expect dual or quad core to be necessary for gaming anytime in the next 9 months..."
Really? That is surprising to hear. 9 months takes us to next July. I thought Alan Wake would definitely be released before then, and I thought that game REQUIRED two cores and would greatly benefit from four. Are you sure that statement isn't supposed to read "We don't expect QUAD CORE to be necessary for gaming anytime in the next 9 months..."?
JarredWalton - Thursday, November 2, 2006 - link
I thought Alan Wake was looking more like late 2007 (along with Unreal Tournament 2007 and some other games). We'll have an article looking into this area a bit more soon, but right now the games aren't out; they're in development, but the "when it's done" attitude often leads to launch dates that get pushed back.floffe - Thursday, November 2, 2006 - link
One game isn't gaming in general ;)johnsonx - Thursday, November 2, 2006 - link
AT Writers:The first chart on page 1 seems to have a typo. It states the Core 2 Quad has a die size of 162mm^2x2. But it shows the Core 2 die size as 143mm^2. If the Quad is just two Core2 dies, then why are they so much bigger?
The quoted die size of the Pentium D 900 at 162mm^2 suggests the source of the typo.
coldpower27 - Thursday, November 2, 2006 - link
As well if were going to be consistent and and call Core 2 Quad as 2x 143mm2 which is the right figure I might add not 2x 162mm2, then the Pentium D 900's should indeed be 2x81mm2 and not 162mm2 as it is stated right now on the chart.coldpower27 - Thursday, November 2, 2006 - link
Continued.. The reason being as the Pentium D is also 2 die on a single package just like Kentsfield as in this case you had 1 core on each die instead of a 2 core per die arragement.Sunrise089 - Thursday, November 2, 2006 - link
All I really needed to know from this article:1) Responsiveness isn't any better from CoreQuad
2) No mainstream software that I might use will take advantage of 4 cores in the near-future.
4) Quad-core does come at a large price increase (it isn't a free-lunch like the first dual-core chips from Intel were)
5) Quad-core doesn't overclock as well.
Decision - almost everyone who buys this at these prices is making a mistake, by the time the software catches up with this everyone will be ready to upgrade again.
eoniverse - Thursday, November 2, 2006 - link
From a gaming perspective definately. But if you render I like the performance increase. Price does suck. However when AMD 'replies' middle of 07 - the prices will adjust.And I'll be buying 'something'.
rowcroft - Thursday, November 2, 2006 - link
Do you think that with four cores, there are other bottlenecks limiting performance? I would think that moving to a striped disk array would be representative of a system that has a $999 processor.With four cores I would imagine there is some disk access contention happening. Especially since the iTunes test using write/reads pretty heavily doesn't it?
I'm no expert, just my thoughts.
EnzoM3 - Thursday, November 2, 2006 - link
Not a fan of one giant strip array. IMO, if disk contention is a problem, isolate the tasks that are contenting for disk access, then put the data on seperate physical drives. I put iTunes on one drive, page file on another, system files on main drive, videos and edits on another, and finally all iso's on one. Disk contention is never an issue even though rest of my system could use upgrades.