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Overclocking: Sandy Bridge Changes The Game

Intel’s Second-Gen Core CPUs: The Sandy Bridge Review
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Although the processing cores in Intel’s Sandy Bridge architecture are decidedly similar to Nehalem, the integration of on-die graphics and a ring bus improves performance for mainstream users. Intel’s Quick Sync is this design’s secret weapon, though.

As you probably already know, Sandy Bridge dramatically alters the way enthusiasts can approach overclocking. For a great many, the days of wringing massive gains out of a scalable architecture like Nehalem are over. Options do still exist, though.

The back-story is already pretty well known. In an effort to simplify its design (which really does make sense from an engineering perspective), Intel integrated the clock generator into the 6-series chipsets. Now, one clock affects the entire system, meaning you can’t independently set the frequencies of various subsystems like PCI Express and the DMI.

Unfortunately, PCI Express doesn’t like to operate very far outside of its specification, so any significant deviation beyond the new 100 MHz BCLK causes problems. Though there’s generally a few percentage points worth of wiggle room, the days of taking Nehalem’s 133 MHz BCLK up to 200+ MHz are history. Overclockers are basically losing one of the two variables that previously affected processor performance. Intel addresses this in two ways.

First, it carries over the unlocked K-series that first surfaced back in May of last year. These parts top out at a 57x ratio multiplier, enabling frequencies of up to 5.7 GHz without touching the BCLK. Intel says the 57x is largely a “design consideration,” whatever that means. The good news for the LN2 crowd is that the company is working on a BIOS that’ll go higher and apply to today’s CPUs. The K-series chips also offer "unlocked" DDR3 memory ratios, which aren't literally unlocked, but rather exposed up to DDR3-2133 (higher than most kits are capable of going anyway). Power and current limits can also be custom-specified, too.

There are only two K-series parts at launch: the Core i7-2600K and the Core i5-2500K. The unlocked i7 costs $23 more than the partially-unlocked version of the same chip, while the i5 runs $11 more expensive than its less-flexible equivalent. When you consider that, at its default settings, the Core i5-2500K runs at 3.3 GHz and Turbo Boosts up to 3.7 GHz, compared to the Core i5-760 at 2.8 GHz, an unlocked Sandy Bridge chip for $11 extra is actually pretty damn sexy.

If you don’t buy a K-series chip and instead grab a Core i7-2600, Core i5-2500, -2400, or -2300 (along with a P67-based motherboard), you’ll still have access to “limited unlocking.” This basically means you can set clock rates up to four speed bins above the highest Turbo Boost frequency setting available at any given level of processor activity.

So, take a Core i7-2600 as an example. The chip’s base clock is 3.3 GHz. With four cores active, it gets one bin worth of additional performance—3.4 GHz. Four bins above that would be 3.8 GHz. With two cores active, Turbo Boost bumps it up two bins, to 3.5 GHz. Limited overclocking makes 3.9 GHz available in that case. In a best-case scenario, only one core is active. Turbo Boost adds four bins of frequency, yielding 3.7 GHz, and Intel’s overclocking scheme lets you run at up to 4.1 GHz.

Anyone with a K-series CPU overclocking on air is going to be in good shape. Thomas and I both have Core i7-2600Ks that’ll do 4.7 GHz at 1.35 V all day long. More mainstream folks with non-K i5s and i7s will at least have an extra 400 MHz to milk from their chips. It’s the value-oriented buyers with processor budgets between $100 and $150 (where AMD offers some of its best deals) who get screwed. The only two Sandy Bridge-based options under $175 are the Core i3-2100 and -2120 at 3.1 and 3.3 GHz, respectively. No Turbo, no BCLK option, no limited unlock—those chips are quite literally stuck.

As with the integrated graphics situation, I think that Intel missed the boat by trying to use overclocking as a differentiating feature. The guys who hit 7 GHz+ in our recent K-series overclocking contest are getting artificially capped. The folks buying at the bottom end of the mainstream stack can’t touch their BCLK or multiplier settings. And unless you buy one of two K-series SKUs, you’re on a Turbo Boost + 400 MHz leash.

Hopefully AMD is taking notes. Though most of its newest 45 nm processors don’t offer a ton of headroom, sticking 32 nm manufacturing later this year could make flexible Bulldozer-based CPUs very attractive to anyone who feels like Intel is muscling them out of overclocking at the high- and low-end.

Display all 22 comments.
  • 4 Hide
    mi1ez , 3 January 2011 19:30
    Great looking processors, tainted by a US only competition.
  • 1 Hide
    aje21 , 3 January 2011 20:33
    I was wondering if the HTPC market would be best served by a return to the "mobile on the desktop" approach which was popular during the Pentium 4 era.
  • 1 Hide
    Anonymous , 3 January 2011 21:46
    Please correct the LGA1555 value on "o Meet Intel’s Second-Gen Core CPUs" to LGA 1155.
    Thanks in advance,
    Regards,
    FJorgeR.
  • 1 Hide
    dillyflump , 3 January 2011 22:42
    Sorry im really not sold on the idea of intergrated gpu's. The intergration of the PCIe bus is a good idea, but i wouldn't want to run the risk of having a chip failure. You would effectively loose two components instead of just the cpu.
  • 1 Hide
    Anonymous , 4 January 2011 01:55
    Any chance you could update this review with screengrabs that show the image quality difference between MediaConverter 7 and MediaEspresso 6? I'm curious why the latter program rendered the video file in only half the time.
  • 1 Hide
    AnUnusedUsername , 4 January 2011 03:09
    It seems that to anyone who uses dedicated graphics, these chips are more or less just more expensive but otherwise not significantly different from the older ones.. Unless integrated graphics on a CPU can beat dedicated, whats the point of including it on any processor thats selling for more than $150 or so? No one is going to pay more than that for a processor and not use dedicated graphics, so its just wasted space and an increased cost that gets users nothing. Seems to me that Intel is just out of ways to noticably improve performance, since higher clock rates get too hot and more cores aren't coded for, so they are just adding more clutter to their chips and selling them as something new... not saying it was simple, but it seems pretty useless to me. Maybe the next release from intel will take advantage of the more advanced CPU and drop the integrated graphics so we get effectively the same performace at a lower price.
  • 1 Hide
    chechak , 4 January 2011 05:27
    H67 does not support processor overclocking + Sandy Bridge HD graphic 3000 suck + no usb 3.0 + Sandy Bridge processors are not compatible with Intel’s 5-series chipsets = intel customer wrath :S !!!
  • 1 Hide
    mosox , 4 January 2011 15:56
    I fail to see anything that changes the game. Another Intel socket that will have only a handful of CPUs on it. No 6 core CPUs on that.
  • 0 Hide
    wild9 , 4 January 2011 22:41
    mosoxI fail to see anything that changes the game. Another Intel socket that will have only a handful of CPUs on it. No 6 core CPUs on that.


    Maybe Ivy Bridge at 22nm, will offer more than 4 physical cores.

    But I feel a similar way to you. Take away the potential of the HD 3000 (which Intel has done with most of the Sandy Bridge portfolio), and what have you got? HD 2000, ring bus and restricted overclocking. Would the average Joe be willing to run out and ditch their i5 for this? Hmm. If the vast majority of these products had Hyper-Threading and HD 3000, I'd be more inclined to say yes. But the current i5 already incorporates decode assist hardware to speed up video transcoding in apps like CyberLink MediaEspresso. As a result the gap between present Core i5 HD graphics and the new Sandy Bridge HD 2000 isn't massive, least not by this measure.

    Source: http://techreport.com/articles.x/20188/17

    Even at stock the current i5 doesn't seem too bad compared to the new i3 and i5, and you can always overclock. So for games in particular I'd just spend it on a faster discrete GPU rather than upgrade to Sandy Bridge.

    As for AMD. Well, once again Intel has fired first with what it perceives to be a silver bullet. Except you have to rummage through a pile of fake bullets to aim straight; 75% of the Sandy Bridge portfolio excludes Intel HD 3000. Thus accelerated computing, and to a greater extent on-die 3D gaming performance, will suffer (AMD 890GX still packs a gaming/hd media playback punch compared to Intel HD 2000). So for everything but media transcoding that just leaves ring bus, controversial overclocking features and a somewhat tight-fisted attitude towards Hyper-Threading on quad-core CPU's..not be a big enough reason for me to ditch my current hardware. AMD's approach seems quite the opposite, focusing on socket longevity and putting next-gen technology in everyone's hands, rather than just the few who can afford it.
  • 2 Hide
    mosox , 5 January 2011 03:52
    The new CPUs look like semi-workstation CPUs to me. Not really much better in gaming but sensibly better in some other areas. I don't know if that's a mainstream direction, I mean who encodes/archives all day long?

    I want AMD to keep on producing cheapo quads and triple cores for the budget gamers out there (I am one). A $100 quad with L3 cache would be nice. And cheap mobos too. Let Intel do its thing on the high end market and concentrate on the 1 billion dudes and dudettes in Africa/China/India/E Europe who want to play Crysis on a cheap rig with a SH Raidmax PSU, an old IDE HDD and the cheapest CPU that can run the game on a 19" monitor.
  • 1 Hide
    Anonymous , 5 January 2011 18:58
    Cheeky! I game on a 22" screen at 1680 x 1050 thank you very much! I run an HD5850 and core2quad 9450 @ 3.2GHz
  • 1 Hide
    mactronix , 5 January 2011 20:11
    A lot of people are down on this release and its easy to see why. Personally i want My CPU to do CPU type things and my GPU to do the Graphics.
    That said its a fine standard to set for a gaming machine, however there are plenty of people who just want to make a PC that will handle vidio which Sandy bridge does plenty well enough. Surf the net and play the odd game. For this type of build you just saved on the cost of the Motherboard and you dont need a GPU at all.
    Everything has to start somewhere and teh GPU side of the package will only get better as we go into 22nm and beyond. Games are not getting anymore taxing and pretty soon. 3 years i will say, i can see only hardcore gamers even needing a discrete GPU at all.

    mactronix
  • 0 Hide
    Anonymous , 6 January 2011 18:36
    Any enthusiast/gamer will be ignoring the integrated gfx and focussing on the K variants. And from this view point, you now have a new CPU that makes almost every other processor completely redundant. No one in their right mind is going to choose P55/X58 over these.

    As an upgrade from an existing i5/i7 setup its not worth it - did anyone really expect it to be? But for a new build or an upgrade from a S775/Q6600 for example, tis a no brainer!
  • 0 Hide
    strat4axe , 6 January 2011 19:04
    With Sandy Bridge and the forthcomming Bulldozer cpu's on their way,as they develop is it going to be possible to use the on die GPU as a physics engine with a discrete graphics card?Like a hybrid graphics solution,only one that's worth bothering with?
  • 1 Hide
    strat4axe , 7 January 2011 22:29
    GO away this ain't ebay
  • 1 Hide
    Gonemad , 7 January 2011 22:56
    mmmkay, these chips ain't exactly targeted at enthusiasts, and a bit of feature malfunction there releasing HD 3000 graphics chip thingie on top tier desktop parts, instead of budget/mainstream, but I certainly do see potential on video encoding for those that live of it.

    On another point of view, discrete sound and network cards were sent on the way of the dodo, when motherboards came with them embedded, leaving behind only really top players in their fields, namely Gigabit NIC, and top-tier soundcards with dedicated or special-purpose hardware.

    I see this trend again, when the CPU has graphic muscle enough to make a discrete graphic card redundant. I mean, one benchmark showed one of these cards tie up with a Radeon HD 4550 and still don't believe it. I see interesting benchmarks on the budget section in the days ahead, where an Intel solution may actually show up on the FPS charts.
  • 0 Hide
    wild9 , 9 January 2011 17:41
    8 consecutive spam messages in a row, with several hours between messages.

    This suggests that a) these spammers are having a field day, and b) that users are avoiding posting altogether due to the sheer volume of spam. I trawled through so much junk to post this, that I almost forgot what I originally came here for.

    Maybe this isn't the place to say it, and I wish to point out I am not trying to say it for no real reason.

    Tom's, what is going on to this great community? These spammers are making a complete and utter mockery of your operation. I like coming here and reading the tech news including people's feedback but if these spammers keep attacking the site like this, it's not worth it for me. I'm wasting time trawling through rubbish and the frustration this causes is really making me look elsewhere. I am confident every other legitimate member of this service feels the same way.

    Why not give trusted users low-level moderator status? Or how about a filter that declares any posts containing text from a spam database, as null and void? I spot several spam posts using the same url, for instance..there's 4 above that could have been wiped out in an instant.

    This is getting crazy, guys. They're ruining it for others.
  • 1 Hide
    mosox , 9 January 2011 17:44
    Probably that's about what you can get if not upgrading unnecessarily to Sandy Bridge. :) 
  • 1 Hide
    Mudit Sathe , 10 January 2011 12:33
    Why a core 980x is not used in this benchmarks?
  • 0 Hide
    weefatbob , 25 January 2011 02:13
    mi1ezGreat looking processors, tainted by a US only competition.

    And every price, for this article posted on UK site, is in dollars too!
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