Overclocking Controversy

It wasn’t until the Pentium II that Intel started shipping multiplier locked CPUs. Before then you could set the multiplier on your CPU to anything that was supported by the line, and if you had a good chip and good enough cooling you just overclocked your processor. Intel’s policies changed once remarking, the process of relabeling and reselling a lower spec CPU as a higher one, started to take off.

While multipliers were locked, Intel left FSB overclocking open. That would be an end user or system integrator decision and not something that could be done when selling an individual CPU. However, ever since before the Pentium III Intel had aspirations of shipping fully locked CPUs. The power of the enthusiast community generally kept Intel from exploring such avenues, but we live in different times today.

Two things have changed Intel’s feelings on the topic. First and foremost is the advent of Turbo Boost. So long as Intel doesn’t artificially limit turbo modes, we now have the ability to run CPUs at whatever clock speed they can run at without exceeding thermal or current limits. We saw the first really exciting Turbo with Lynnfield, and Sandy Bridge is going to expand on that as well. On the flip side, Intel has used Turbo as a marketing differentiator between parts so there’s still a need to overclock.

The second major change within Intel is the willingness to directly address the enthusiast community with unlocked K-series SKUs. We saw this recently with the Core i7 875K and Core i5 655K parts that ship fully unlocked for the overclocking community.


The K-series SKUs, these will be more important with Sandy Bridge

With Sandy Bridge, Intel integrated the clock generator, usually present on the motherboard, onto the 6-series chipset die. While BCLK is adjustable on current Core iX processors, with Sandy Bridge it’s mostly locked at 100MHz. There will be some wiggle room as far as I can tell, but it’s not going to be much. Overclocking, as we know it, is dead.

Well, not exactly.

Intel makes three concessions.

First and foremost we have the K-series parts. These will be fully unlocked, supporting multipliers up to 57x. Sandy Bridge should have more attractive K SKUs than what we’ve seen to date. The Core i7 2600 and 2500 will both be available as a K-edition. The former should be priced around $562 and the latter at $205 if we go off of current pricing.

Secondly, some regular Sandy Bridge processors will have partially unlocked multipliers. The idea is that you take your highest turbo multiplier, add a few more bins on top of that, and that’ll be your maximum multiplier. It gives some overclocking headroom, but not limitless. Intel is still working out the details for how far you can go with these partially unlocked parts, but I’ve chimed in with my opinion and hopefully we’ll see something reasonable come from the company. I am hopeful that these partially unlocked parts will have enough multipliers available to make for decent overclocks.

Finally, if you focus on multiplier-only overclocking you lose the ability to increase memory bandwidth as you increase CPU clock speed. The faster your CPU, the more data it needs and thus the faster your memory subsystem needs to be in order to scale well. As a result, on P67 motherboards you’ll be able to adjust your memory ratios to support up to DDR3-2133.

Personally, I’d love nothing more than for everything to ship unlocked. The realities of Intel’s business apparently prevent that, so we’re left with something that could either be a non-issue or just horrible.

If the K-series parts are priced appropriately, which at first indication it seems they will be, then this will be a non-issue for a portion of the enthusiast market. You’ll pay the same amount for your Core i7 2500K as you would for a Core i5 750 and you’ll have the same overclocking potential.

Regardless of how they’re priced, what this is sure to hurt is the ability to buy a low end part like the Core i3 530 and overclock the crap out of it. What Intel decides to do with the available multiplier headroom on parts further down the stack is unknown at this point. If Intel wanted to, it could pick exciting parts at lower price points, give them a few more bins of overclocking headroom and compete in a more targeted way with AMD offerings at similar price points. A benevolent Intel would allow enough headroom as the parts can reliably hit with air cooling.

The potential for this to all go very wrong is there. I’m going to reserve final judgment until I get a better idea for what the Sandy Bridge family is going to look like.

The Roadmap & Pricing The Test
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  • Anand Lal Shimpi - Friday, August 27, 2010 - link

    We'll have to wait a little bit to find out... :) Reply
  • hnzw rui - Friday, August 27, 2010 - link

    If it doubles Clarkdale's GPU performance, then it probably will (at least on lower resolutions). I'm getting pretty decent framerates from Clarkdale on 1360x768 Low and I've been able to play on 1360x768 Medium with a Radeon HD 4550. I think Sandy Bridge is probably closer to the latter than the former in performance. Reply
  • SteelCity1981 - Friday, August 27, 2010 - link

    Any word when Intel will launch a mobile version of this new platform? Reply
  • Anand Lal Shimpi - Friday, August 27, 2010 - link

    Q1 2011 :) Reply
  • BSMonitor - Friday, August 27, 2010 - link

    So glad I waited on a 13" macbook pro! Sandy Bridge will probably be the next revision for Macbook's ehh? Reply
  • cheinonen - Friday, August 27, 2010 - link

    Exactly my thoughts, that the GPU performance looks to be good enough that Apple could use it for the 13" MBP refresh next year. I'll be glad that I decided to wait, that's fur sure. Reply
  • synergist - Friday, August 27, 2010 - link

    I was doing some research and if they would have to use the full integrated graphics core, with the 12 cores, to top the performance of the 320M in the current macbook pro 13 I doubt apple would take a step backwards in gfx performance, and use the 6 core integrated gfx.

    and the performance would still be pretty close, that the 320M would lose to the inter grated gfx (12 cores) by about 10-13%

    and llano is still an option, but I have a feeling it will be a dead heat with this.
    Reply
  • starfalcon - Friday, August 27, 2010 - link

    Apple has to know a lot of the people buying the laptops are far from high end gamers.
    The amount of people with 320Ms who don't need them is probably a lot.
    We'll see how all the different parts of Sandy Bridge work out.
    Don't the Core iX processors not work with Nvidia Integrated graphics at all?
    Reply
  • JarredWalton - Friday, August 27, 2010 - link

    Correct on NVIDIA IGPs not working with Core 2010 (and presumably beyond). The need the QPI interface and Intel isn't licensing that to them.

    As for Apple, one thing to note is that they've started shipping all laptops with GPUs that support OpenCL it seems, so if Sandy Bridge doesn't have that they may do the same Optimus-style setup as current MBP. Not sure what they'd do with the base MacBook in that case, but Apple seems like they're gearing up to start leveraging OpenCL at some point in the near future. Pure speculation, though, so maybe SB's IGP will be enough, even if it's a step down from G320M.
    Reply
  • DanNeely - Friday, August 27, 2010 - link

    Aside from on the high end (LGA 1366/2011) the bus nVidia needs is DMI, not QPI. If I was nVidia I'd insist on getting rights to both because QPI is more futureproof. Specifically having more than a few high speed SATA6GB/USB3/etc devices will be able to saturate DMI since it's only the equivalent of a PCIe 4x slot (1.0 speed for 1156, 2.0 for 1155/2011) while QPI is a much higher capacity bus similar to AMD's HyperTransport.

    While intel seems determined to milk as much out of the (presumably) cheaper to implement DMI bus as it can; sooner or later they're going to either need to mainstream QPI or have the CPU die eat the SATA/USB3 controllers. I find the latter unlikely because it would require cramming even more data lines into the already overcrowded CPU socket area.
    Reply

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