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.
Facebook
Twitter
RSS
200 Comments
View All Comments
seapeople - Sunday, August 29, 2010 - link
So you're saying that integrated graphics should either be able to handle high resolution gaming using at least medium settings on the upper echelon of current games or they should not be included? That's fairly narrow minded. The bottom line is that most people will never need a better graphics card than SB provides, and the people who do are probably going to buy a $200+ graphics card anyway and replace it every summer, so are they really going to care if the integrated graphics drive the price of their $200 processor up by $10-20? Alternatively, this chip is begging for some sort of Optimus-like option, which will allow hardcore gamers to buy the graphics card they want, AND not have to chew up 100W of graphics power while browsing the web or watching a movie.Regardless, for people who aren't hard core gamers, the IGP on SB replaces the need to buy something like a Radeon HD 5450, ultimately saving them money. This seems like a positive step to me.
chizow - Sunday, August 29, 2010 - link
No, I'm saying if this is being advertised as a suitable discrete GPU replacement, it should be compared to discrete GPUs at resolutions and settings you would expect a discrete GPU to handle and not IGPs that we already know are too slow to matter. 1024x768 and all lowest settings doesn't fit that criteria. Flash and web-based games don't either, since they don't even require a 3D accelerator in order to run (Intel's workaround Broadcom chip would be fine).Again, this card wouldn't even hold a candle to a mid-range $200 GPU from 3 years ago, the 8800GT would still do cartwheels all over it. You can buy these cards for much less than $100, even the GT240 or 4850 for example have been selling for less than $50 after MIR and would be a much more capable gaming card.
Also, you're badly mistaken if you think this GPU is free by any means, as the cost to integrate a GPU onto SB's die comes at the expense of what could've been more actual CPU....so instead of better CPU performance this generation, you lose that for mediocre graphics performance. There is a price to pay for that relatively massive IGP whether you think so or not, you are paying for it.
wut - Sunday, August 29, 2010 - link
You don't know what you're talking about. You pretend that you do, but you don't.The telling sign is your comment about L2/L3 cache.
chizow - Sunday, August 29, 2010 - link
Actually it sounds like you don't know what you're talking about or you didn't read the article:"Only the Core i7 2600 has an 8MB L3 cache, the 2400, 2500 and 2600 have a 6MB L3 and the 2100 has a 3MB L3. The L3 size should matter more with Sandy Bridge due to the fact that it’s shared by the GPU in those cases where the integrated graphics is active. I am a bit puzzled why Intel strayed from the steadfast 2MB L3 per core Nehalem’s lead architect wanted to commit to. I guess I’ll find out more from him at IDF :)"
You might've missed it very clearly stated in the tables also that only the 2600 has the same 8MB L3 or 2MB per core with previous 4C like Bloomfield/Lynnfield/Westmere/Clarkdale. The rest have 6MB or 3MB, which is less than 8MB or 4MB L3 used on the previous generation chips.
This may change with the high-end/enthusiast platform, but again, the amount of L3 cache is actually going to be a downgrade on many of these Sandy Bridge SKUs for anyone who already owns a Nehalem/Westmere based CPU.
wut - Friday, September 10, 2010 - link
You're parroting Anand and his purely number-based guess. Stop pretending.mac2j - Saturday, August 28, 2010 - link
990x is a Gulftown part on 1366 that's 130MHz faster than the 980x.... will cost $1000 and come out the same time as the 2600 (which will cost ~ 1/2 and deliver 90% of the performance) and at most a couple months before the i7-2800K which will cost less and trounce it performance-wise.You'd have to REALLY want those extra cores to buy a 990x on a lame-duck socket at that point!
wut - Sunday, August 29, 2010 - link
Some has to get those chips to populate the uppermost echelons 3DMark score boards. It's an expensive hobby.hybrid2d4x4 - Saturday, August 28, 2010 - link
Anand, can you provide some more info on what the system configuration was when running the power tests? The test setup lists 2 vid cards and it's not clear which was used when deriving the power graphs. Also, what PSU was used?Just wondering since if it was a 1200W behemoth, then the 63W idle might really be 30W on a more reasonable PSU (assuming no vid cards)...
As always, thanks for the article!
smilingcrow - Saturday, August 28, 2010 - link
Was HT enabled for the power tests and what application was used to load the cores?semo - Saturday, August 28, 2010 - link
No USB3.0 support and a half baked SATA3 implementation. I could be a bit too harsh about the latter (can't say if SATA3 on a 6 series chipset will perform poorly or not) but why are they going with only 2 6Gb/s ports? I understand that most people are likely to be buying only 1 or so SSDs in the near future but what about in a few years when these things become mainstream? At least AMD took SATA3 seriously even if they couldn't quite make it work initially (we need a follow up on the 8 series chipsets' SATA performance!)Not only are Intel overlooking advance in technologies other than CPUs (which are important to most consumers, whether they are aware of it or not) but are also denying other companies who might have more focus in those areas. I wonder if Nvidia or someone else bother to release a chipset for Intel's latest and greatest.