Overclocking Core i7: Power Versus Performance
Table of contents
- 1. Does it Make Sense To Go for Maximum Performance?
- 2. Hardware: Core i7 920, Asus X58, Corsair DDR3
- 3. Overclocking Choices And Details
- 4. From 2.66 To 4.0 GHz
- 5. Test System
- 6. Benchmark Results: Games
We've seen a great number of processors from Intel with impressive overclocking margins, which means that they can be operated at amazingly high clock speeds, often as high as 30-50% above the specified clock rate. However, extreme overclocking increases power consumption, especially if increased processor voltage is required to reach the desired clock speeds (as we saw in our Phenom II Overclock Optimization story).
Today, we look at an Intel Core i7 920 system to find the best speed settings to deliver truly high performance at still acceptable power consumption levels.
Overclocking Is A Feature
While early overclocking attempts in the late 1990s were only possible on select motherboards that supported fine-tuning of bus speeds, multipliers, and voltages, the status and perception of overclocking is different today. Any average motherboard supports basic overclocking features, and the high-end products are almost built around overclocking—it has become a true feature and a key selling point, rather than merely a dangerous amusement.
While only a small percentage of all users actually decide to run their systems heavily overclocked—keep in mind that not everyone is an enthusiast—overclocking as a feature has to be available to be able to sell anything positioned above the budget price range (even if overclocking isn’t specifically mentioned as an option).
Everyone Can Overclock
Many products—chipsets, processors, graphics chips and more—are built based on comfortable, if not ample, tolerances. As a result, lots of components can safely be operated at speeds much higher than their base specifications. Overclocking is now widely supported on a plethora of platforms, making it easy and rather safe for everyone to overclock.
If you stick to reasonable clock speed increases of 10-20%, almost every processor will run smoothly and reliably, providing noticeable performance benefits at negligible risk for your hardware. All you need to do is choose automatic overclocking settings, which is possible on many higher-class motherboards, and increase the system speed settings by 10-20%. Voila—done.
How Fast Should You Go?
Of course, an increase of only 10-20% may not be enough; your neighbor or work mate may be running much faster settings reliably. However, there are limits to overclocking, at which it starts making only limited sense to go farther.
We assembled a test system based on Intel's Core i7 920 and looked at the possible performance gains, in addition to the increased power consumption you have to expect as a result. The findings are amazingly obvious, and illustrate that there is a practical limit to overclocking that it doesn’t make sense to go beyond.
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typo on oc page.
1275v for cpu voltage @ 183mhz
It looks like we could use an i7 version of AMD Overdrive.
There will be times, especially in my line of work, where I need to do some seriously intensive work that a hefty overclock, like the 3.8 or 4GHz, will greatly benefit me, however my everyday operation wouldn't need to go much past stock speeds.
Storing OC profiles in a real-time utility would be fantastic: fire up the stupid 4GHz mode when I need to render my 20 minute HD graphic sequence, switch to 3.33GHz for some gaming, and drop to 2.6 stock to check my e-mail.
Yes, the 4GHz mode sucks stupid levels of power, but if you have the freedom to run it in short spells then it's easier to live with.
I thought though this test was sticking with the stock Intel cooler - what's that hefty copper thing then on page 5?
Thank you for this article, I'm going build an I7 920 / Asus P6T setup at the end of may when the i5 / P55 components come out, I'm waiting mainly for price reasons. I currently run an AMD 3200+ Barton / Asus A7N8X setup which seriously needs to be replaced.
This article is exactly what I want, I've a novice overclocker and any guidance is welcomed. I'm running a Koolance water cooling solution and it'll be used for my new i7 920 setup, I'll definitely be overclocking it to 3.33Ghz to begin with, and the maybe 3.6Ghz at a later date to prolong it's life with regards to performance.
What is the PSU used? Does it have a factor on the testing?
does anyone really need to overclock such a fast quad core chip
@pete3867:
If you want to spend £850 on the 3.2GHz model then go right ahead. The rest of us will save £600 and overclock our 2.66GHz model and match performance.
The question has never about if you "need" to overclock. Strictly speaking you don't need to overclock because there's a faster model than you can just buy.
But we're always looking to get the most for our money in every walk of life, and certainly with CPUs over the past few years if you can match performance of a more expensive model by overclocking a cheaper one, then frankly you'd be insane not to do it.
Besides, "fast" is a relative term. Right now, the i7 does wet on everything around it so *right now* you may not "need" to do anything with it. However, who knows what's around the corner to beat these things - in a few years you may "need" to overclock your investment to keep pace with what's around.
yeah , I guess your right , I just feel that in general terms modern cpu 's are (at the moment at least )way ahead of the software demands placed on them .
@pete3867:
Again, it depends on what you're doing. If an Atom-based netbook can do office and web stuff perfectly well then why do you need a Core i7? Gaming has always been more about the GPU for a quite while now so until recently you could get away with an older CPU.
Media creation, on the other hand, can never have too much processing power. At work I upgraded my ageing P4 3.2GHz to a (then) shiny Core 2 Duo 2.4GHz and was blown away by how much power I had and how much faster I could do all my stuff. Very quickly though I used up that potential knowing I could do more with it than before, so now I'm back to long render times.
We had some 8GB Quad Core systems in and the same applied there - marvelled at the power increase, only to be negated by me doing more with it. The same will apply to by stupid i7 rig I build in a few months.
Basically, in media creation you can never have too much power, and as I stated in my first post, having an Overdrive-style utility where I can quickly enable "stupid 4GHz overclock mode" for my renders would be so good - we need every ounce of juice we can muster.
Your results are biased towards the setups not operating at stock voltage. If you increase voltage when overclocking, you should also undervolt where possible rather than use stock voltage.
It looks like we could use an i7 version of AMD Overdrive.There will be times, especially in my line of work, where I need to do some seriously intensive work that a hefty overclock, like the 3.8 or 4GHz, will greatly benefit me, however my everyday operation wouldn't need to go much past stock speeds.Storing OC profiles in a real-time utility would be fantastic: fire up the stupid 4GHz mode when I need to render my 20 minute HD graphic sequence, switch to 3.33GHz for some gaming, and drop to 2.6 stock to check my e-mail.Yes, the 4GHz mode sucks stupid levels of power, but if you have the freedom to run it in short spells then it's easier to live with.
I completely agree, nowadays an OC profile system would be much more versatile. Compared to older systems, which may demand a constantly OC'ed CPU, newer systems at stock should rival older OC'ed systems. Profile's for power management would be an excellent idea.
Hey, LePhuronn check out http://www.overclockingwiki.org/in [...] =Clockgen.
Fixed link: http://www.overclockingwiki.org/in [...] e=Clockgen
You can run 3.33GHz with Turbo mode on much lower than stock voltages. I'm currently running it on 1.15V and it could probably be lower than that. This would obviously make 3.33GHz an ever more appealing choice when looking at power consumption.
What a hike in power consumption to get that thing stable at 4GHz..
An OC compromise that works very well for me as a permanent setting and which doesn't cause me i920 core temps above 55degC whether under gaming or under Prime is: CPU and QPI parity at 3240MHz by means of 180MHz base clock, x18 CPU multiplier, 20x Uncore multiplier (i.e. Uncore clock 3600MHz) & 10x Memory Multiplier (i.e my 6GB of OCZ memory at 1800MHz, set 8-8-8-26). Air cooler is a Thermalright u120e & mobo is an EX58-UD5. All voltages are stock. 30days of excellent glitch-free performance so far. I have no ambition to go for bigger numbers & like to keep things simple.