Power Consumption
Sandy Bridge-E isn’t on the same tick-tock cadence as Intel’s desktop processors. We’re a few months away from the next “tick,” in the form of Ivy Bridge, and here we are evaluating the performance of a “tock”-derivative.
That’s not bad news by any stretch of the imagination. Intel nailed its 32 nm lithography node, giving the company a mature process on which to build this 2.27 billion-transistor, 434 square-millimetre processor. Gulftown, in comparison, is comprised of 1.17 billion transistors in a 248 mm2 die. Despite that disparity in size and composition, Intel manages to work Sandy Bridge-E into a 130 W TDP, just like the Core i7-990X.
| Processor | Idle System Power Consumption |
|---|---|
| Intel Core i7-3960X (Sandy Bridge-E) | 87 W |
| Intel Core i5-2500K (Sandy Bridge) | 90 W |
| Intel Core i7-2600K (Sandy Bridge) | 90 W |
| AMD Phenom II X4 980 (Deneb) | 100 W |
| AMD FX-8150 (Zambezi) | 111 W |
| AMD Phenom II X6 1100T (Thuban) | 114 W |
| Intel Core i7-990X (Gulftown) | 127 W |
| Intel Core i7-920 (Bloomfield) | 130 W |
And yet, at idle, Core i7-3960X behaves a lot like a 95 W Sandy Bridge desktop processor, dropping down to less than 90 W of system power use measured after 10 minutes of sitting on the Windows desktop. In comparison, Bloomfield (Core i7-920) and Gulftown (Core i7-990X) are much more power-hungry at idle.
After measuring idle system power use, I ran and logged complete runs of PCMark 7 to track average power use in a more graphically-representative way. In order to keep the chart from getting too muddled, I only left Core i7-3960X, Core i7-990X, and FX-8150. You can see, though, in looking at the peaks and dips, that Sandy Bridge-E is using less power than either of its competitors.
Averaging system power use gives us this list:
| PCMark 7 System Power Consumption, Logged In Two-Second Intervals | |
|---|---|
| Processor | Average Power Across One Run |
| Intel Core i5-2500K (Sandy Bridge) | 153 W |
| Intel Core i7-2600K (Sandy Bridge) | 155 W |
| Intel Core i7-3960X (Sandy Bridge-E) | 172 W |
| AMD Phenom II X4 980 (Deneb) | 184 W |
| Intel Core i7-990X (Gulftown) | 189 W |
| AMD Phenom II X6 1100T (Thuban) | 191 W |
| AMD FX-8150 (Zambezi) | 191 W |
| Intel Core i7-920 (Bloomfield) | 193 W |
Core i7-3960X indeed uses less power, on average, than the 130 W Gulftown- and Bloomfield-based parts. It’s bested only by Intel’s 95 W Sandy Bridge processors. Even AMD’s older Phenom II X4 and X6 chips are more power-hungry (as is FX-8150).
| Prime95 x64 Small FFTs System Power Consumption | |
|---|---|
| Processor | Power Consumption After 5 Minutes |
| Intel Core i7-2600K (Sandy Bridge) | 175 W |
| AMD Phenom II X4 980 (Deneb) | 221 W |
| AMD Phenom II X6 1100T (Thuban) | 230 W |
| Intel Core i7-3960X (Sandy Bridge-E) | 253 W |
| Intel Core i7-990X (Gulftown) | 263 W |
| AMD FX-8150 (Zambezi) | 264 W |
Of course, PCMark 7 doesn’t push processors to their limit. For that, we turn to Prime95, which I didn’t run in our FX-8150 review, but include here with most of the platforms in that story re-tested.
Core i7-3960X on Intel’s DX79SI board cuts peak power consumption by 10 W compared to Core i7-990X on Asus’ Rampage III Formula, which itself uses 1 W less than AMD’s FX-8150 on Asus’ Crosshair V Formula.
Core i7-2600K is the only CPU able to facilitate a less-than-200 W system power number, dipping in at 46 W less than the second-place finisher, AMD’s Phenom II X4 980 Black Edition.
Surprised at the savings, especially compared to the smaller and less complex Gulftown design, I asked Intel to help explain how Sandy Bridge-E could possibly use less power. The response was that two cores in the 2.27-billion transistor die are completely fused off, and that a number of other power/speed path improvements were made to help cut the CPU’s draw.
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Wow, I am so underwhelmed. My 2600K is looking better and better ha, ha. Yea there is an average performance increase of 17% over my 2600K but this CPU costs $1000 - honestly I don't get the $700 difference other than it MAY support PCI-E 3.0 (we don't know for sure). For those that use Premier Pro and ABBYY Fine Reader and other specific programs like them, then yes there is a real tangible benefit.
For gamers there is virtually no real benefit worth $700. It is entertainingly funny that SLI performance doesn't change much between the 2600K and the 3960X. The only real benefit to gamers will again be PCIE 3.0 support IF the Sandy Bridge E chips will support this.
I guess I was expecting more oomph from this new flagship. A measly 17% average performance increase over my $292.00 2600K makes me think that I have the best CPU available for the money. When we see how the new Sandy Bridge E CPUs overclock this may change greatly because there is every indication that they will be amazing overclockers. That coupled with PCI-E 3.0 capability may provide some separation between the Gen 2 and Gen 3 E CPUs.
Is it really that suprising though since they are the same cores? Nobody really expected much more than a marginal increase core for core, the difference in the platform comes with addition of those two extra cores (in the hexcore chips obviously) that are not available in the standard sandybridge package.
And, don't compare with the top end six core but the 3930 which offers far better value for money for those extra cores, extra cache and the platform advantage of 4 channel memory with a cheap 32GB option or more expensive 64GB option - again, something that is not available to the cheaper sandybridge platform.
Nobody knows what performance increase Ivybridge will bring, it may be great but will still be limited to four cores in the standard platform, hopefully Ivybridge-E wont take longer than this time next year and will offer at least a six core option if not eight core to the desktop if Intel don't decide to kill the two extra cores as they have done with the desktop sandybridge-e
Is the main selling point for this over the gulftown the improved energy efficiency?
The Visual Studio benchmark looks suspicious to me: A 6 core only showing a few percentages improvement vs a quadcore? What is the unit of time of that test, minutes or seconds? Compilation should be perfectly scalable (with the correct tools).
OK first of all, great article. Really enjoyed reading about the new processors. I was a bit miffed there wasn't a Cinebench score as Cinema4D is what I live in. I'll add those scores here for anyone interested.
Straight i7-3960X = 10.55
Overclocked = 12.31
Anyone into 3D and Cinema in particular will be looking at those figures and drooling. Is it worth the cash considering everything you need to buy if you render at home? not really. You can get close to a 10 score with an overclocked i7-2600k and the massive expense of a 3960 could see you building two or three 2600k boxes to get scores of close to 20 and 30 respectively. Of course that's only going to be meaningful to animation heads using separate machines to render different frames in an animation, but as that's really all they need, more cores, more gigahertz's, Intels latest offerings aren't priced right to attract them.
Looking at the cheaper chip, it still doesn't really make sense to go for it in a graphics workstation. You will get far more performance and value from just building the cheapest second 2600k box you can. A big shame really as it feels like we are doomed to a certain level of computing in one computer for at least the next two years with small percentage bumps along the way unless you're willing to go way out there on the money tree.
Intel are a bunch of meanie heads putting the prices of these so far out of reach of us peons.
Take heart, Ivy Bridge is coming out int 2012 and hopefully it will be the real-meal deal. I am somewhat stunned that my 2600K has such staying power. Except for the new PCI-E 3.0, I don't see much reason for upgrading my CPU.
Still, that being said, when you take a look at the performance increases on some specific programs they can be dramatic - some are as much as 50% faster than the 2600K. There is some real improvement in many areas with the 3960X.
Take heart, Ivy Bridge is coming out int 2012 and hopefully it will be the real-meal deal. I am somewhat stunned that my 2600K has such staying power. Except for the new PCI-E 3.0, I don't see much reason for upgrading my CPU.Still, that being said, when you take a look at the performance increases on some specific programs they can be dramatic - some are as much as 50% faster than the 2600K. There is some real improvement in many areas with the 3960X.
@flong I agree the top end chip especially is a beast. For the kind of work I do it would be a huge benefit but as I'm only a hobbyist at this, these prices can't be paid for by saying a next big budget job will pay for the new hardware as any real business could.
Also I think as even the Toms article points out, with the perspective change on the 2600k initially looking a bit of a miss up against the almost as good 2500k. Looking at it today the 2600k clearly shines when placed in line with these new chips. So it's less about the 2600k holding its own and more about Intel refusing to let us all at the good stuff in new hardware, instead concentrating on super high profit margins they can get from business.
I'm assuming the enthusiast and really anyone falling in the can only afford a 2600k market is quite small compared to where these 3960X's are being targeted so at least until that sector gets chips that are much faster again than the 3960X's, I don't really see Intel giving us anything significantly better for at least the next two years. Whatever launches next year can't really be as fast as a 3960X and priced just above a 2600k or it would invalidate the pricing structure they already have in place. So really how can you expect anything more than a few percent bump?
With AMD floundering around like sad fishes out of water, Intel just have no reason to really push the value.
"This news just in" Fire brigade saved the day at a local IT business today, the fire initially started when staff decided to cook their fried breakfasts on the AMD Bulldozer server cases instead of ordering out. Fireman Sam who was at the scene is urging others not to cook on AMD products but suggests heating sandwiches in bulldozer hot swappable drive bays is OK"
I think that Ivy Bridge is supposed be a step up from Sandy Bridge E, but I am really tired right now ha, ha.
I really don't why anyone is even the least bit surprised with the small performance increase of Intel's new extreme CPU.
People everywhere have always paid dearly for that last little bit of performance and it really doesn't matter whether we are talking about tennis rackets, fishing poles or technology!
The last 10% will always cost exponentially more than the first 90% .