
The Core 2 Quad Q9550S has the full 12 MB L2 cache, while the Q8200S only has 4 MB total cache memory. The Core 2 Duo E8500 runs a total of 6 MB L2 cache. In the end, the idle power difference is insignificant. All three processors, including the 2.83 GHz Q9550S, are very efficient when they idle.

The dual-core requires the least power at peak load, while the entry-level quad-core isn’t too far behind. The Core 2 Quad Q9550S boosts the power consumption from 39 W when idle to 106 W at CPU peak power, a 67 W difference. Keep in mind that the power supply adds to the power consumption with its efficiency of 82%, so the Intel low power quad core clearly stays within its power specifications.
Power Supply Impact

Here are the power consumption results measured with the three different power supplies. The low power 220 W FSP220 power supply by Fortron is the most efficient, as it was designed for low power systems. Enermax’s Pro82+ also does very well, requiring only a little more idle power—it is even more efficient with the Core 2 Quad Q9550s once you throw CPU load at it.
Beware of older PSUs, though. The EG565P-VE by Enermax is a product that is three years old. Efficiency wasn’t on the priority list at that time, which results in 6 to 11 W of additional power consumption if you use an older device. It clearly makes sense to purchase an efficient and suitable power supply if you want a truly efficient system.
Check prices for Intel's Core 2 Quad Q9400S
It would have been nice if the benchmarks would have included the equivalent "non s" model core 2 quads.
Yay the money you save as a home user is completely negated by the price increase. 1.5 years later it might show, and by then your energy saving version of a processor that has been out already for months is even more obsolete.
Big businesses however might benefit, but most workstation computers run on garbage parts just enough to keep a browser and word open.
What's the use of such overpriced products when you can get better efficiency with core i7 and similar idle consumption for only some $$$ more. And why only three processors? The review published at Anandtech http://www.anandtech.com/cpuchipse [...] spx?i=3505 more than a month ago is much better. (Of course it doesn't include Q8200s but that doesn't matter much)
another "great" article...........
like previously posted way to also bench the "NON s" model....
This would\'ve been a great product a year or two ago, but IMHO it\'s only a smart buy today if let\'s say you\'re still holding on to your original Conroe Core2 e6300 that you bought the day it came out, and want to upgrade to a quad(assuming that your motherboard will support it, I believe we\'ve all been dissapointed before wanting to upgrade an Intel CPU and discovering that we have the right socket, but the wrong chipset...).
any Overclocking?
It would have been nice if the benchmarks would have included the equivalent "non s" model core 2 quads.
I at least expected the power consumption and power measurements to compare the non-"S" models.
While it is nice to know how these quads do compared to a dual core, we all want to know whether its worth the investment buying the "S" version rather that the std. models currently available.
I was kind of jumping back and forward did it ever mention how the 'S' cpu's overclocks compared to the non-'s' ones? I keep thinking lower TDP would actually reduce the O.C. capabilities. And ya, wished they would have compared it w/ the non-'s' ones... bummer.
No, it didn't give any overclocking information, which would have been nice. And, certainly, comparisons to the non-S versions should have been included. The article is somewhat silly without the comparison.
These benches are worthless without comparing them to the equivilent Q8200/Q9550. Why do I care how these new things compare to the E8500, and not the other Q-series chips they're replacing? It's cool to have a dual-core in there...but please...comparative gogo?
I have to agree with a lot of posters that the non-s versions should have been included. I do think some people would have liked to see over-clock figures, but I'm happy to see real-life comparisons. Final thoughts: this should help bring down the non-s prices, which works for me. And please people, don't bring up Anandtech ... their benchmarks are suspect as I feel they favor their best advertisers, and they like to block out opposing opinions on their website. I gave up on them several years ago after following their advise and making some pretty bad decisions. Never again!
The 80Plus chart states that Gold requires 97% efficiency at 100% load. Please correct it to state 87%. Thanks.
Supply and demand determine prices. They feel the demand for the low power processors is enough that the prices will sell them out of supply. If they cannot move the parts fast enough at the price, the price will drop, or they will stop binning for that power envelope, even though the processors will still be lower power.
If you had compared these quad-cores to, say an E8300 running at 2.83GHz, wouldn't we have seen the Q9550S use twice as much power at 100% load, seeing as a Q9550S is basically two E8300's slapped together.
Also, why wouldn't Intel market their 45nm duo's at a lower TDP (AMD likes their 45W TDP BE-series Athlons). Seems to me nothing adds up here.
I'll be waiting for more meaningfull benchmark comparisons.
I have to agree with the others. This review REALLY needs to compare these energy efficient models with their, less efficient brethren. That's where the real difference is.

And I have to admit, I'd like to have seen some OC numbers. My first thought when I saw the article was, "Oh cool, maybe they'll OC higher now too."
Of course I have no idea if the chips OC at all now.
what happened to the overclock?
65 W CPU generally are the better overclockers. Overclocking is the really important information that I want from this article, and compared with the same model at 95W, and other equally costly processor.
It allow to decide best buys.
The overclocking ability is a big question. But then most businesses that use these would not overclock anyway. And maybe energy efficient quads would find their way into more laptops.
I've been curious about processors like the P9500. It seems to be a fairly fast dual core processor, and it is at only 25W. Are they not used in desktops because of their high price? Was energy saving in a desktop not considered important until recently?
Any chance you can an E6600 to the graphs to give us a good baseline for comparison?