The Sandy Bridge Preview
by Anand Lal Shimpi on August 27, 2010 2:38 PM ESTOverclocking 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.
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iwodo - Sunday, August 29, 2010 - link
The GPU is on the same die, So depending on what you mean by true "Fusion" product. It is by AMD's definition ( the creator of the tech terms "Fusion" ) a fusion product.iwodo - Sunday, August 29, 2010 - link
You get 10% of IPC on average. It varies widely from 5 % to ~30% clock per clock.None of these Test have had AVX coded. I am not sure if you need to recompile to take advantage of the additional width for faster SSE Code. ( I am thinking such changes in coding of instruction should require one. ) AVX should offer some more improvement in many areas.
So much performance is here with even less Peak Power usage. If you factor in the Turbo Mode, Sandy Bridge actually give you a huge boost in Performance / Watts!!!
So i dont understand why people are complaining.
yuhong - Sunday, August 29, 2010 - link
Yes AVX requires software changes, as well as OS support for using XSAVE to save AVX state.BD2003 - Sunday, August 29, 2010 - link
It sounds like intel has a home run here. At least for my needs. Right now I'm running entirely on core 2 chips, but I can definitely find a use for all these.For my main/gaming desktop, the quad core i5s seem like theyll be the first upgrade thats big enough to move me away from my e6300 from 4 years ago.
For my HTPC, the integrated graphics seem like theyre getting to a point where I can move past my e2180 + 9400 IGP. I need at least some 3d graphics, and the current i3/i5 don't cut it. Even lower power consumption + faster CPU, all in a presumably smaller package - win.
For my home server, I'd love to put the lowest end i3 in there for great idle power consumption but with the speed to make things happen when it needs to. I'd been contemplating throwing in a quad core, but if the on-die video transcoding engine is legitimate there will be no need for that.
Thats still my main unanswered question: what's the deal with the video encoder/transcoder? Does it require explicit software support, or is it compatible with anything that's already out there? I'm mainly interested in real time streaming over LAN/internet to devices such as an ipad or even a laptop - if it can put out good quality 720-1080p h264 at decent bitrates in real time, especially on a low end chip, I'll be absolutely blown away. Any more info on this?
_Q_ - Sunday, August 29, 2010 - link
I do understand some complains, but Intel is running a business and so they do what is in their best interest.Yet, concerning USB 3 it seems to be too much of a disservice to the costumers that it should be in, without any third party add-on chip!
I think it is shameful of them to delay this further just so that they can get their LightPeak thing into to the market. Of which I read nothing in this review so I wonder, when will even that one come?!
I can only hope AMD does support it (haven't read about it) and they start getting more market, maybe that will show these near sighted Intel guys.
tatertot - Sunday, August 29, 2010 - link
Lightpeak would be chipset functionality, at least at first.Also, lightpeak is not a protocol, it's protocol-agnostic, and can in fact carry USB 3.0.
But, rant away if you want...
Guimar - Sunday, August 29, 2010 - link
Really need oneTriple Omega - Sunday, August 29, 2010 - link
I'm really interested to see how Intel is going to price the higher of these new CPU's, as there are several hurdles:1) The non-K's are going up against highly overclockable 1366 and 1156 parts. So pricing the K-models too high could mean trouble.
2) The LGA-1356 platform housing the new consumer high-end(LGA-2011 will be server-only) will also arrive later in 2011. Since these are expected to have up to 8 cores, pricing the higher 1155 CPU's too high will force a massive price-drop when 1356 arrives.(Or the P67 platform will collapse.) And 1366 has shown that such a high-end platform needs the equivalent of an i7 920 to be successful. So pricing the 2600K @ $500 seems impossible. Even $300 would not leave room for a $300 1356 part as that will, with 6-8 cores, easily outperform the 2600K.
It will also be quite interesting to see the development of those limits on overclocking when 1356 comes out. As imposing limits there too, could make the entire platform fail.(OCed 2600K better then 6-core 1356 CPU for example.) And of course AMD's response to all this. Will they profit from the overclocking limits of Intel? Will they grab back some high-end? Will they force Intel to change their pricing on 1155/1356?
@Anand:
It would be nice to see another PCIe 2.0 x8 SLI/CF bottleneck test with the new HD 6xxx series when the time comes. I'm interested to see if the GPU's will catch up with Intels limited platform choice.
thewhat - Sunday, August 29, 2010 - link
I'm disappointed that you didn't test it against 1366 quads. The triple channel memory and a more powerful platform in general have a significant advantage over 1156, so a lot of us are looking at those CPUs. Especially since the i7 950 is about to have its price reduced.A $1000 six-core 980X doesn't really fit in there, since it's at a totally different price point.
I was all for the 1366 as my next upgrade, but the low power consumption of Sandy Bridge looks very promising in terms of silent computing (less heat).
SteelCity1981 - Sunday, August 29, 2010 - link
What do you think the Core i7 980x uses? An LGA 1366 socket with triple channel memory support. So what makes you think that the Core i7 950 is going to perform any diff?????