Intel's Sandy Bridge Architecture Exposed
by Anand Lal Shimpi on September 14, 2010 4:10 AM EST- Posted in
- CPUs
- Intel
- Sandy Bridge
Final Words
Intel is trying out a new approach to sharing information about its technologies. In an attempt to surprise the market (and potentially positively impact stock price), Intel is keeping details on upcoming products quiet until it gets closer to launch. This is why we didn’t hear about Sandy Bridge until after we were able to preview its performance a couple of weeks ago. I can’t say I’m a fan of the new approach, but it does make things a little more exciting.
And exciting Sandy Bridge is. The CPU architecture itself doesn’t look too revolutionary. These are the sorts of improvements we’ve come to expect from Intel from one generation to the next. The out of order execution window grew as did all associated buffers. Thanks to some significant redesigns in hardware Intel was able to increase branch prediction accuracy and FP execution throughput all while making the chip more energy efficient.
Improved turbo will surely be appreciated. More aggressive turbo bins plus the ability to turbo up above TDP limits for short periods of time will help make PCs feel more responsive even when doing relatively benign tasks. Things like launching applications, loading web pages or just opening new window stand to benefit.
The architecture sounds a lot like Intel simply did Nehalem/Westmere better. Over time you come up with newer, better ways to do things and that’s ultimately what Sandy Bridge looks like - a better, more efficient way to do what Conroe, Nehalem and Westmere did before it.
The more dramatic changes happened outside of the cores. GPU performance is clearly an important Sandy Bridge feature as we’ve already shown. I can’t help but be curious about how far Intel could take its SNB graphics subsystem if it simply scaled up the number of EUs. The media processing engine, particularly with the video transcode support is very exciting. Assuming image quality is maintained and there’s good software support at launch, this could very well be Sandy Bridge’s killer feature. The ability to transcode at over 10x real time on everything from a desktop to a notebook is just awesome. With good software support, SNB’s video transcode engine could effectively stop consumer GPU based video encoding in its tracks. The improved video decode engine is also a welcome addition to the Sandy Bridge architecture.
Connecting it all together we have Sandy Bridge’s ring bus. Generally microprocessor designs don’t undergo such a radical changes unless the design will be used for a while to come. The ring bus sounds very scalable and should support growth in core count, L3 cache and GPU performance. This may end up being the base architecture that takes us from multi-core to many core.
Mobile Sandy Bridge is significantly faster than Arrandale/Clarksfield
Sandy Bridge will ship in Q1 2011 for both notebooks and desktops and from what we’ve heard, pricing will be very compelling. If you're interested in a sneak peak of Sandy Bridge's performance, take a look at our preview here.
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yuhong - Tuesday, September 14, 2010 - link
There is no VEX.256 for 256-bit integer ops, but there is a VEX.128 prefix that zeros the upper part of YMM registers to reduce the delays..NaN42 - Tuesday, September 14, 2010 - link
Well, I found a summary of the prefixes. Interestingly there are some exception, like I guessed, e.g. a VEX.128 prefix does not exist for conversion of packed floating points<->packed integers and for CRC32c + POPCNT.CSMR - Tuesday, September 14, 2010 - link
Anand:The best info available on an exciting platform, good job.
I wonder if for the next article you could test DirectX / OpenGL compatibility? Intel advertises compliance for a lot of its products, but in reality the support is partial, and some applications that use DirectX / OpenGL entirely correctly are not supported by Intel graphics, including the current HD graphics.
I've found this with fastpictureviewer (DirectX, I think 9) and Photoshop CS5 (OpenGL 2)
This is quite shocking. Given that Intel is doing this currently, it would be great if reviewers could prod it into action, but unfortunately they tend to place speed first, correctness second or nowhere.
marass31 - Thursday, September 16, 2010 - link
Hi CSMR,Could you please write more details about problems with DX and OGL on Intel HD graphics( including gfx driver version, system config ...). You mentioned about two applications: Fastpictureviewer and PSCS5, so could you please write some steps to reproduce to each of them - THX a lot.
ssj4Gogeta - Tuesday, September 14, 2010 - link
What's the point of extreme editions if we're going to have affordable K SKUs?Or will socket 2011 not have any K SKUs? I'm guessing they'll leave the BCLCK unlocked on the 2011, and only have normal and extreme processors (no K processors). Or maybe extreme editions will just have more cores like 980X?
DanNeely - Tuesday, September 14, 2010 - link
The extreme editions have always been for people who buy retail or who're playing with LN2 and need the most insanely binned part available. They've never been a mainstream OCer part.MonkeyPaw - Tuesday, September 14, 2010 - link
I have a bad feeling about the "k" chips and the future of overclocking. Sure, intel gave us turbo mode, but that almost seems like appeasement before the last shoe drops. First, limited turbo with good overclockng, then better turbo and less overclocking, and now it's sounding like slightly better turbo and even less overclocking. It looks like we are moving to intel-controlled overclocking. There's virtually no value left for the enthusiast--a user that is already just a small part of the market. Intel just decided what the enthusiast needs, but I don't think they get what those users actually want.I just don't buy that these limits are to prevent fraud. Mom and Pop stores are virtually all gone now, and I'd hate to think what Intel would do to a Dell or HP if they got caught overclocking desktops.
I guess this leaves another door open for AMD. Sad, cause SnB looks like a great design.
This Guy - Wednesday, September 15, 2010 - link
Hopefully Intel will allow the 'energy budget' to be increased when an extreme edition processer detects less thermal resistance (i.e. a bloody big heat sink). This would allow an EE CPU to either run with a higher multiplier or run at it's turbo frequency longer. (I'ld like this feature on all CPU's)This would make EE CPU's interesting if K CPU's catch up in terms of cores.
Shadowmaster625 - Tuesday, September 14, 2010 - link
What are the prospects for using Intel's transcoder to convert DVDs to 700MB avi files? Either DivX, Xvid, or H.264? Or anything else better than MPEG-2?Dfere - Tuesday, September 14, 2010 - link
Since this seems to be, overall, a refinement, and not so much an improvement with new capabilities, and Anand's comments about the scalability of GPU related enhancements, that Intel is taking a two step approach towards CPU releases, in addition to its fab strategies? E.G, we see a new CPU, then it gets shrunk, then it gets improved (like this), then it gets bells and whistles (like a GPU etc), then we start over again with a really new architecture.....