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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gruffi - Friday, August 27, 2010 - link
Why not comparing with a HD 5570? That is what Llano is supposed to have, Redwood-class IGP. An HD 5450 is quite pointless. It just reflects competition for Ontario. But Sandy Bridge is not Ontario's competition.And what about image quality or GPGPU support? Pure FPS numbers are only half of the truth.
wiak - Friday, August 27, 2010 - link
dont think so, its said that AMD's Fusion built-in GPU will have 400 SPUs (HD 5670 level-graphics), thats a far cry from HD 5450's 80 SPUs ;)so if you wanna game you still have to use something from a real graphics manufacture like AMD when it comes to GPUs bult into CPUs, as a added bonus you also have updated drivers and a decade old DirectX 9 compatibility, so you old games work without any big problems
icrf - Friday, August 27, 2010 - link
I am impressed that you have a functioning sample at least four months before it's available, run it through enough paces for a review like this, and they let you release the numbers. I mean, are they trying to suppress holiday sales?When do you think you'll have a Bulldozer sample from AMD to run a similar preview? Barring a surprise from AMD, at this point, it looks like I'll be building an i7 2600 early next year. The similar spec chip from today is an i7-975 Extreme, which is the fastest quad core in the bench, and Sandy Bridge runs 13-14% faster in the only benchmark I care about (x264). I guess even that might change significantly if it can take advantage of this "alleged on-die video transcode engine." I'd not heard of that before.
Anand Lal Shimpi - Friday, August 27, 2010 - link
Honestly we're probably several months out from having Bulldozer silicon in a similar state. With the past few generations of Intel CPUs, by around 4 - 6 months before launch we're usually able to get access to them and they perform very well.With AMD the lead time is far shorter. I don't expect us to have access to Bulldozer silicon that's worth benchmarking until Q2 2011 at the earliest. I'm more than happy to be proven wrong though :-P
icrf - Friday, August 27, 2010 - link
I guess I'm mostly surprised that Intel would do it. Conroe made sense. They had to show the world as early as possible that they had something significantly faster than AMD, suppressing sales of that for their own a little later. But now that they own that performance crown, why show previews so many months early? I suppose I could be over-analyzing it and the vast majority of the market couldn't care less so it makes little difference to their bottom line. Bragging rights simply make for good PR.Sad to see Bulldozer so far out. I assume the server chips will ship before the consumer ones, too, so it'll be at least a solid year before it could be in my hands, anyway. Oh well. To be honest, my C2D E6400 still does well enough for me. Maybe I'll just make my upgrade an Intel G3 SSD. If I got both that and SB, I don't know what I'd do with myself.
Thanks, and keep up the good work.
Anand Lal Shimpi - Saturday, August 28, 2010 - link
This preview wasn't Intel sanctioned, I believe Intel will release its own numbers at IDF in a few weeks.Take care,
Anand
icrf - Saturday, August 28, 2010 - link
Oh, I had assumed you got this chip from Intel and they had a typical NDA that said when you could talk about what you found. Where'd it come from, then? One of Intel's motherboard partners with whom you have a friendly relationship?aegisofrime - Saturday, August 28, 2010 - link
I must say, I'm really grateful for this article. I'm in the middle of planning an upgrade and information like this is really valuable to me. (and I guess to a lot of people as well!) I would just like you to know that your articles actually do influence some of our buying choices. So... Thank you! :DNow, all I need is a Bulldozer preview and all the pieces are in place...
vajm1234 - Friday, August 27, 2010 - link
few things clear and few unclear as of nowthis sandy bridge review sample here do not have TURBO enabled. The CPU runs at 3.1GHz all the time, regardless of workload as anand stated
it says "Both the CPU and GPU on SB will be able to turbo independently of one another. If you’re playing a game that uses more GPU than CPU, the CPU may run at stock speed (or lower) and the GPU can use the additional thermal headroom to clock up. The same applies in reverse if you’re running something computationally intensive."
QUESTIONS
Q} will the on die GPU unit work in tandem with the other discrete GPUs out there or it will shut off? if yes will it work when sli or crossfire is enabled :p
Q} whatever the above statement says will it happen if we use discrete graphics from nvidia or ati?
Q} will there be any possibility to disable ONLY GPU and in certain cases ONLY its TURBO FEATURE
Q} any possibility to remain the GPU overclocked the whole time when cpu is IDLE
Q} what about accelerated hd video playback using the on die gpu?
Q} it support VT-x and AVX is it possible for you anand to use specific benchmark for these instructions, same request goes for the AMD
Q} as someone asked will there be a cheap 6 => core processor for mainstream market
Q} again as per the last comment ......When do you think you'll have a Bulldozer sample from AMD to run a similar preview?
this Ques Must be answered
all n all what i think even if there is a 15-19% perf. Jump its not worh the spending when u consider u have to upgrade the entire platform
and moreover limiting Overclocking features damm! a retarded decision i am not in a mood for amd but if the overclocking hits then i will move 10000...% :angry:
regards
DanNeely - Saturday, August 28, 2010 - link
If you're asking about an SLI/CFX pairing with the IGP almost certainly not. The only company to ever attempt something like that has been Lucid with the Hydra chip and the results have been less than impressive. Architecturally I don't know that it'd even be possible for them to try with the on die GPU. The Hydra chip sat between the CPU and the Gfx cards on the PCIe bus and looked like a single card to the OS. There's no way for them to insert themselves into the middle of the connection to the IGP.