In one breath Intel dramatically cut pricing on its Core 2 Quads. Intel’s swift response was even faster than NVIDIA’s after the RV770 launch. In the following breath however, Intel introduced new, lower power, and much higher priced Core 2 Quad CPUs. Enter the S-line.

TDP binning is something that AMD has done for quite a while on the desktop. The e-suffix parts (e.g. Phenom X4 9350e) are lower TDP parts, sold at a premium, to those users who need lower power consumption.

The Phenom X4 9350e and the 9150e are both 65W quad-core parts from AMD, while all of Intel’s quad-core CPUs have been 95W. Unwilling to allow AMD any sort of advantage, Intel has finally responded with 65W quad-core offerings of its own. The difference here is that while AMD’s 65W quad-cores are all significantly lower clocked Phenom processors, Intel’s 65W chips are available at up to 2.83GHz.

The Core 2 Quad Q9550S, Q9400S and Q8200S are all 65W TDP quad-core CPUs. They share the same specs as their non-S brethren. The only difference here is that instead of being 95W TDP parts, these CPUs can fit in a 65W thermal envelope.

Processor Clock Speed L2 Cache L3 Cache TDP Price
Intel Core i7-965 Extreme Edition 3.20GHz 1MB 8MB 130W $999
Intel Core i7-940 2.93GHz 1MB 8MB 130W $562
Intel Core i7-920 2.66GHz 1MB 8MB 130W $284
Intel Core 2 Quad Q9650 3.00GHz 12MB - 95W $316
Intel Core 2 Quad Q9550S 2.83GHz 12MB - 65W $369
Intel Core 2 Quad Q9550 2.83GHz 12MB - 95W $266
Intel Core 2 Quad Q9400S 2.66GHz 6MB - 65W $320
Intel Core 2 Quad Q9400 2.66GHz 6MB - 95W $213
Intel Core 2 Quad Q8300 2.50GHz 4MB - 95W $183
Intel Core 2 Quad Q8200S 2.33GHz 4MB - 65W $245
Intel Core 2 Quad Q8200 2.33GHz 4MB - 95W $163


The price premium for these new S-parts is huge. The Q9550S costs $103 more than the non-S, the Q9400S will set you back another $107 and the Q8200S is the most affordable with only an $82 premium. Note that in the case of the Q9550S and Q9400S you're actually more expensive than the entry level Core i7-920.

Intel achieves these lower TDPs by running at a lower core voltage. With a mature enough manufacturing process, which Intel’s 45nm process is, it’s quite possible to produce CPUs that run much cooler than average and on a lower voltage. CPU power varies with the square of the voltage, so any savings in voltage can result in a non-linear decrease in power consumption.

Don’t get too excited however. If you remember back to our review of the 9350e/9150e we found that the decrease in power wasn’t worth the added price. Even Intel has come forward and told us that these are primarily OEM parts and not intended for the high volume enthusiast community. With Intel being honest in its intended purpose for these S-class CPUs we don’t really have to do much to keep them honest, we just need to confirm the findings.

To do this we took a subset of our regular CPU performance tests and looked at performance, power consumption and power efficiency. We measured total system power consumption at the wall outlet, which does admittedly lessen the impact of a lower power CPU but it should give us an idea of the real world benefit of these processors. If you want to see how the Q9550/Q9550S performs across our entire suite of benchmarks take a look at AnandTech bench, our new publicly available benchmark database.

...and in case you’re wondering, no, they don’t overclock any better. Our Q9550S couldn’t get any further than the Q9550 we used in our Phenom II review.

The Test

CPU: AMD Phenom II X4 940 (3.0GHz)
AMD Phenom 9950 (2.6GHz)
Intel Core i7-965 (3.2GHz)
Intel Core i7-920 (2.66GHz)
Intel Core 2 Extreme QX9770 (3.2GHz/1600MHz)
Intel Core 2 Quad Q9650 (3.00GHz)
Intel Core 2 Quad Q9550S (2.83GHz)
Intel Core 2 Quad Q9450 (2.66GHz)
Intel Core 2 Quad Q9400 (2.66GHz)
Motherboard: Intel DX58SO (Intel X58)
Intel DX48BT2 (Intel X48)
MSI DKA790GX Platinum (AMD 790GX)
Chipset: Intel X48
Intel X58
Chipset Drivers: Intel (Intel)
AMD Catalyst 8.12
Hard Disk: Intel X25-M SSD (80GB)
Memory: G.Skill DDR2-800 2 x 2GB (4-4-4-12)
G.Skill DDR2-1066 2 x 2GB (5-5-5-15)
Qimonda DDR3-1066 4 x 1GB (7-7-7-20)
Video Card: eVGA GeForce GTX 280
Video Drivers: NVIDIA ForceWare 180.43 (Vista64)
Desktop Resolution: 1920 x 1200
OS: Windows Vista Ultimate 64-bit
Adobe Photoshop CS4 Performance
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  • carniver - Wednesday, January 28, 2009 - link

    makes sense indeed
  • AffenJack - Wednesday, January 28, 2009 - link

    some results look strange like x264
    Phenom2, q9400 and q9450 have the same speed and same average power.
    Shouldn't they have the same total energy comsumption?
    I would say there's something wrong in this chart.

  • xahydra - Wednesday, January 28, 2009 - link

    BeHardware reviewed the q9300 awhile back and tested consumption directly from the voltage rail and found it never pulled more than about 45 watts full load. This is consistent with the fact that the q9300 and its q8000 series cousins typically pull about 30W+ less than the q6600. Intels own processor information finder shows identical voltages for the 9300 and this "S" series CPU and the voltages are identical.. Only thing different is the stepping. Could the q9300 have been labeled as a 50W part had Intel cared to do so? Or even a 65W for that matter (giving margin of yield variation)?">">
  • philosofool - Wednesday, January 28, 2009 - link

    You're right that the Core i7 is overall a more efficient machine. However, the S series are LGA775 chips, which means that could fall into the upgrade path for many users, or simply be the chip of choice for someone interested in an $85 board and power friendly chip. It's the added premium of X58 and triple channel DDR3 memory that sets th Core i7 cost outside of the mainstream, not just the cost of the chip itself. Otherwise I'd be looking at a Core i7 machine right now....
  • 7Enigma - Wednesday, January 28, 2009 - link

    I have a hard time wrapping my mind around a low(er) TDP part that cannot OC better than a non low TDP-binned processor? Is it just that the one you have for testing is a uniquely "gifted" cpu? It's my understand (correct me if I'm wrong) that lower TDP parts are due to superior construction that reduces leaks that would otherwise just go to heat production. If this is the case I can't see why a lower TDP part couldn't OC higher....

    Please enlighten me as it doesn't make a lot of sense. Oh and thanks for the review because I'm sure I'm not the only one that just assumed a lower TDP part would on average OC better than a higher TDP part.
  • JarredWalton - Wednesday, January 28, 2009 - link

    Lower power parts can come from a variety of things, but binning is a major impact. In many cases, chips that need less voltage run cooler and OC better; likewise, chips that *can* run with less voltage can also run fine at higher speeds with a "normal" voltage. That puts Intel (and AMD) in the position of binning for several options: do you want a low power chip, a high default MHz chip, or some combination of the two?

    My guess would be that a lot of the QX9650/QX9770 and similar "extreme" CPUs can run at lower voltages and lower MHz. However, Intel might take CPUs that bin successfully at high clocks first, and then bin the remaining to see if some can run at lower voltage, which could then account for S-series chips that don't OC any better than regular chips.

    Also remember that overclocking depends on many areas of the CPU, so it could be that these low voltage chips also tend to have limitations elsewhere -- maximum OC will always depend on the weakest link in the chip, which is why we see variability. Perhaps this being an ES chip has an impact, or it could just be random luck. Good or bad luck, that's the question.

    I'm sure some S-series chips will overclock slightly better than regular Penryns, but at the end of the day the last 100-400 MHz really only matters to people running competitive benchmarks. Heck, I'm still running a Q6600@3.30GHz, and I have never encountered any situation where I think, "I wish my CPU had a little more oomph...." YMMV, naturally.
  • 7Enigma - Friday, January 30, 2009 - link

    Thank you for the very informative reply! And I agree it should make it into the original article to preempt the inevitable question.
  • StraightPipe - Thursday, January 29, 2009 - link

    Thanks. This is a great explaination.

    I wish it had made it into the main article.
  • WillR - Wednesday, January 28, 2009 - link

    Anand, can you provide any further explanation why Intel’s power gate transistors gave the i7 a higher energy efficiency on the Fallout 3 test in terms of Joules but didn't actually give it a lower "at the wall" power draw in average watts? I'm just not following why it's making any difference in joules when it's not in watts (compared to the P2 940) if the dt is the same.

    Also, any interest in adding testing of the 50 watt Xeon L5420 to the benchmark database? Intel has had low voltage parts for almost a year, they just haven't brought them into the consumer products until now. For the most part they've been ignored by review sites.
  • DeepBlue1975 - Wednesday, January 28, 2009 - link

    About the temperature advantage, I think the results are not trustworthy enough because there is no software that can accurately measure the absolute temperature of the cores.
    Even though Intel disclosed the tjunction max spec for their 45nm parts, they also said that the measure is not completely precise because each chip has a different tj max temperature that can not be read from any register.

    Only i7's tj max can be obtained directly from the chip, so that the absolute core temperature can be better calculated.

    Also on Intel's presentation, they stated that the DTS' readings are not accurate enough for measuring idle temps. Anyway this doesn't apply to this article as you're comparing mainly load temps, not idle ones, and when under load and the more the on die temp approaches tj max, the more accurate the DTS' reading becomes.

    And as the Tcase temp is read and by a motherboard's sensor (at least AFAIK from the available Intel's docs), it isn't completely reliable either.

    Aside from that, excellent article. Not many sites measure the "performance per watt" factor. The only thing I'd add to this article, is a direct comparison with a non-s 9550 e0 chip, specially in the overclocking department, as I tend to think that "cooler chips" will be actually most wanted by overclockers than by energy savers (mainly considering the high price premium)


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