Sign in with
Sign up | Sign in

Overclocking Sandy Bridge-E

Intel Core i7-3960X (Sandy Bridge-E) And X79 Platform Preview
By

There is a silver lining, though. Sandy Bridge-E is expected to be overclockable in ways Sandy Bridge is not.

Two of the three SKUs purportedly planned for launch will be multiplier-unlocked, simplifying overclocking quite a bit. Both of those models should support ratios as high as 57x (just like the Sandy Bridge-based K-series SKUs were), easily taking care of the air-cooling community. The third, Core i7-3820, will get a number of accessible bins on top of the highest Turbo Boost multiplier, similar to Core i5-2500 and Core i7-2600.

But whereas P67 and Z68 employed internal clock generators, X79’s BCLK comes from a CK505 embedded clock fed through a buffer (a chip that follows Intel’s DB1200GS Differential Buffer Specification) responsible for “gearing” the frequency.

With Sandy Bridge, if you didn’t have an unlocked K-series SKU, or a partially unlocked Core i5/i7, then you were pretty much stuck. Changing the BCLK frequency directly affected other buses, quickly affecting stability. We’ve been able to push single-digit increases, but anything more than 9 or 10 MHz is asking for trouble. Of course, Intel's intention there wasn't nefarious. By integrating the clock, it cut power use and cost on the 25 and 14 MHz crystals. Inflexible scaling just turned out to be a side-effect.

Sandy Bridge-E should alleviate this somewhat by using the buffer chip to apply one of three different ratios to the BCLK. These will modify the PCI Express bus and DMI, creating a greater range of viable frequency settings. I emphasize the word should because I wasn’t able to get the mechanism working on our lab system. Increasing the BCLK and dropping our -3960X’s multiplier simply kept the platform from POSTing, no matter what combination of settings I used.

At least at first, the question to answer is going to be: who cares, anyway? When you consider the Core i7-2600K is completely multiplier-unlocked, who is going to want to fight a partially-unlocked quad-core -3820 on an expensive new X79-based motherboard? The extra 2 MB of L3 cache, two additional memory channels, and PCI Express-rich processor probably won’t inspire many upgrades. The real candidates for greatness are the six-core models, both of which Intel thankfully leaves unlocked. Specifically, I’m excited to see what the Core i7-3930K can do.

Display all 171 comments.
This thread is closed for comments
Top Comments
  • 27 Hide
    wicko , September 12, 2011 5:07 AM
    Just bought a 2600k, and after reading this I have no regrets.
  • 26 Hide
    tri force , September 12, 2011 4:51 AM
    "AMD FX-8150 (Zambezi) 3.6 G...Alright, that's just mean"

    I felt really happy for a second :( 
  • 25 Hide
    Tamz_msc , September 12, 2011 5:54 AM
    I hope Bulldozer is more interesting than this. I honestly dont see many enthusiasts investing in this - they're better off waiting for Ivy Bridge.
Other Comments
  • 26 Hide
    tri force , September 12, 2011 4:51 AM
    "AMD FX-8150 (Zambezi) 3.6 G...Alright, that's just mean"

    I felt really happy for a second :( 
  • 10 Hide
    xyster , September 12, 2011 4:54 AM
    awesome! thx 4 the preview chris. i've been looking forward to this
  • 27 Hide
    wicko , September 12, 2011 5:07 AM
    Just bought a 2600k, and after reading this I have no regrets.
  • 23 Hide
    jprahman , September 12, 2011 5:18 AM
    I was really looking forward to Sandy Bridge-E, but it looks like a mixed bag from the review. The lack of USB 3 and especially PCI-E 3 was really disappointing, especially for an enthusiast class processor and chipset. The dearth of SATA ports was pretty surprising too, everything up to this review had indicated far more.

    The extra performance you can get looks pretty nice for stuff like transcoding, but the performance in the majority of applications doesn't justify the extra cost for the i7-3960. I'd rather get a i7-2600K or i5-2500K... or wait for Bulldozer to see how it performs relative to an i5-2500k or i7-2600k.

    To be honest, this review almost comes off like an attempt to chill any interest high-end enthusiasts might have for Bulldozer.
  • 9 Hide
    hmp_goose , September 12, 2011 5:32 AM
    I predict a "meh" from enthusiast … And a far number of LGA1366 drivers looking for a price cut. ;-)
  • 18 Hide
    Wamphryi , September 12, 2011 5:51 AM
    I just got an i7 2600 K and like a previous writer commented I have no regrets either. The 2600 K is such good bang for buck and lots of people seem to be snapping them up.
  • 25 Hide
    Tamz_msc , September 12, 2011 5:54 AM
    I hope Bulldozer is more interesting than this. I honestly dont see many enthusiasts investing in this - they're better off waiting for Ivy Bridge.
  • 24 Hide
    raclimja , September 12, 2011 6:18 AM
    what a massive disappointment, i was hoping for big performance improvement from intel


    i guess i will just stick with my i5 2500k and upgrade my aging HD 4870 x2 to something like GTX 680 or HD 7900
  • 13 Hide
    dalauder , September 12, 2011 6:54 AM
    You say the i7-3820 will be a tough sell, but maybe, like the i7-2600, it will be an excellent non-overclocked part for OEM machines. For that purpose, I think a machine that can run DDR3 1600MHz at without overclocking is a reasonable upgrade over the i7-2600.

    There is a market for people who want top-end gaming machines but never want to look inside other than to add more graphics. Based off of Cyberpower, IBuyPower, Alienware, etc.--I bet that market is at least as big as enthusiasts that hand pick their parts.
  • 21 Hide
    dalauder , September 12, 2011 7:00 AM
    leeashtonwell said people forget that clock for clock the phenom II out performs the Core i7 but not for brute performance
    I'd like to see where you heard that. Based off of this, it appears that the Phenom II only matches a Core 2 Duo, looses to Nehalem, and gets its butt handed to it by SB: http://www.tomshardware.com/reviews/processor-architecture-benchmark,2974.html

    I love AMD, but the argument can't be made for their performance. They do well at extremely low price points now and Llano on the desktop is great for the extremely light gamers that want some gaming capability (OEM do-it-all machines). But for the enthusiast, or quoting performance, AMD desperately needs Zambezi to do more than I expect is possible.
  • 2 Hide
    compton , September 12, 2011 7:01 AM
    I'm not really surprised at all. I'm interested in how power efficient X79 is compared to the stellar performance per watt of the 2500K/2600K. If the new SB-E parts idle anywhere near as low as SB does, it will be impressive. The platform itself isn't really as impressive if it does end up launching in this configuration -- but plain ol' Sandy Bridge is already pretty impressive. I'm still blown away by my 2500K and a couple of Intel SSDs, so I can't imaging myself benefiting from X79. I know there are many enthusiasts out there running older X58 setups who are going to upgrade to X79 no matter what, but I pick and choose my battles. The value of 1155 K parts and P/Z chipsets is hard to overcome.

    Ivy Bridge could be where it's at.
  • 20 Hide
    iam2thecrowe , September 12, 2011 7:16 AM
    Intel gives us a preview, AMD gives us false BD hope and more delays........... I never had a bad thing to say about AMD until recently, they really are hanging by a thread in my books.
  • -8 Hide
    SteelCity1981 , September 12, 2011 7:21 AM
    So this is it from Intel? Seems like a lot of hype for nothing. The Core Core 17 2600x isn't that far behind in the benchmarks overall thn the Core i7 3960x. not to mention the Core i7 3960x barely edges out the Core i7 990x in the vast majority of the benchmarks that it replaced.
  • 17 Hide
    jasonw223 , September 12, 2011 8:02 AM
    Going to skip X79 most likely!
  • 20 Hide
    tomskent , September 12, 2011 8:07 AM
    i7-3960X is a nice bump in performance for highly threaded apps, that said, 95% of the consumers wont need it. A 2500k is more then enough, especially when overclocked.
    Cant wait to see what Bulldozer can do, what Ivy Bridge can do, what the new gen video cards can do. An exciting next several months!

  • 0 Hide
    Agges , September 12, 2011 8:30 AM
    Fingers crossed that this brings a price drop on the LGA 1366 line..

    Okay, very optimistic of looking at the past but one can dream.
  • -4 Hide
    agnickolov , September 12, 2011 8:37 AM
    The 3.6GHz clock on 3820 is of most interest to me for a software development workstation. That's 200MHz over 2600 at the same price and the clock matters the most for compilation. Of course the platform cost will be higher... The 6 threads of 3930K are interesting as well - 6 files compiling in parallel instead of 4, though that makes no difference for still single-threaded linking. The biggest problem I expect is there will be no business-friendly offerings based on X79 - they will all center on Xeons.
  • 14 Hide
    FunSurfer , September 12, 2011 8:59 AM
    For anyone who wondered what the hell is "Gesher" - it means "Bridge" in hebrew.
  • 15 Hide
    ronch79 , September 12, 2011 9:57 AM
    I really look forward to the day when I see SB-E, IB and BD being pitted against each other.
Display more comments