Intel's Haswell Architecture Analyzed: Building a New PC and a New Intel
by Anand Lal Shimpi on October 5, 2012 2:45 AM ESTPlatform Retargeting
Since the introduction of Conroe/Merom back in 2006 Intel has been prioritizing notebooks for the majority of its processor designs. The TDP target for these architectures was set around 35 - 45W. Higher and lower TDPs were hit by binning and scaling voltage. The rule of thumb is a single architecture can efficiently cover an order of magnitude of TDPs. In the case of these architectures we saw them scale all the way up to 130W and all the way down to 17W.
In the middle of 2011 Intel announced its Ultrabook initiative, and at the same time mentioned that Haswell would shift Intel's notebook design target from 35 - 45W down to 10 - 20W.
At the time I didn't think too much about the new design target, but everything makes a lot more sense now. This isn't a "simple" architectural shift, it's a complete rethinking of how Intel approaches platform design. More importantly than Haswell's 10 - 20W design point, is the new expanded SoC design target. I'll get to the second part shortly.
Platform Power
There will be four client focused categories of Haswell, and I can only talk about three of them now. There are the standard voltage desktop parts, the mobile parts and the ultra-mobile parts: Haswell, Haswell M and Haswell U. There's a fourth category of Haswell that may happen but a lot is still up in the air on that line.
Of the three that Intel is talking about now, the first two (Haswell/Haswell M) don't do anything revolutionary on the platform power side. Intel is promising around a 20% reduction in platform power compared to Sandy Bridge, but not the order of magnitude improvement it promised at IDF. These platforms are still two-chip solutions with the SoC and a secondary IO chip similar to what we have today with Ivy Bridge + PCH.
It's the Haswell U/ULT parts that brings about the dramatic change. These will be a single chip solution, with part of the voltage regulation typically found on motherboards moved onto the chip's package instead. There will still be some VR components on the motherboard as far as I can tell, it's the specifics that are lacking at this point (which seems to be much of the theme of this year's IDF).
Seven years ago Intel first demonstrated working silicon with an on-chip North Bridge (now commonplace) and on-package CMOS voltage regulation:
The benefits were two-fold: 1) Intel could manage fine grained voltage regulation with very fast transition times and 2) a tangible reduction in board component count.
2005 - A prototype motherboard using the technology. Note the lack of voltage regulators on the motherboard and the missing GMCH (North Bridge) chip.
The second benefit is very easy to understand from a mobile perspective. Fewer components on a motherboard means smaller form factors and/or more room for other things (e.g. larger battery volume via a reduction in PCB size).
The first benefit made a lot of sense at the time when Intel introduced it, but it makes even more sense when you consider the most dramatic change to Haswell: support for S0ix active idle.
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Penti - Saturday, October 6, 2012 - link
Also FPU/SIMD has been a large part in later ARM designs and implementations. It's really a big deal as we saw with the chips lacking some of those parts. You shouldn't forget how important those bits are. Others have failed because they didn't take it seriously. That was 15-20 years ago even. Doesn't mean they are yet fighting x86-64 chips in high-end servers and workstation though. We will certainly see them entering that market by 2015 though.Arbee - Friday, October 5, 2012 - link
Cortex A9's big IPC improvement came from going out-of-order, which kind of ruins your argument.Similarly, the X360/PS3 PowerPC chips are strict in order and super ultra slow as a result - at 3.2 GHz they can't match a PowerMac G5 with out-of-order at 2.2 GHz. But I suspect that wasn't the point - Sony and MS can claim the eye-popping (in 2006) 3.2 GHz figure, and the heat production is certainly less than a PPC G5.
wumpus - Friday, October 5, 2012 - link
Has anyone seen an A9 in the wild? I don't doubt huge IPC improvements (back when O-O-O was new, it tended to double performance). My statement is that it will kill GIPS/W and that Intel can much more easily design a chip that can beat it in both raw performance and GIPS/W (note that your mention of heat production agrees with me).Also note I suspect that the goal of A9 is to keep the power low enough to keep it out of where Intel wants to go. A rough guess is that ARM might have a chance with dual issue o-o-o, but past that (roughly where Pentium Pro was designed) they can't really go.
ElvenLemming - Friday, October 5, 2012 - link
The Cortex A9 has been in most major phone/tablet SoCs for the past two or so years. Apple's A5, A5X; Samsung's Exynos 4210, 4212, 4412; TI's OMAP 4 series; Nvidia's Tegra 2 and 3.Cortex A15 is probably what you were thinking of that we've yet to see out in the wild. It's out-of-order like the A9, but with a great deal of other improvements.
ericore - Friday, October 5, 2012 - link
Currently AMD has the upper hand on the notebook segment on battery life. Haswell changes that, but as is always the case with Intel, they will be pricey. And that's why AMD will still have 50% of the market because vendors are cheap.Power savings are much less relevant on desktop front; I don't care so much about power as i do of heat. AMD X4 700, ship an awsome 4 core cpu for 75$. Technically, it has all that you need from a CPU. Add a Radeon 7770 (again cheap) and your golden. Ya Intel is faster, but both Intel and Nvidia have shitty low end products and that's even more true when you think of atom. 5-15% single threaded performance is not anything that is going to burry AMD lol.
On top of that, AMD has an atom KILLER, a contracts with all major console vendors.
Haswell will have surprisingly little impact on AMD; what I am saying is if you look at your own expectations, you'll realize they were highly inflated and you'll wonder why it didn't do more damage to AMD. I've explained the why. Nevertheless broadwell is a significant threat, and we'll probably see AMD start to lose market share (much more than with haswell) unless AMD can fight back and it will; but nobody knows if it will be enough.
A5 - Friday, October 5, 2012 - link
Uh, wow.Zink - Saturday, October 6, 2012 - link
http://www.tomshardware.com/reviews/gaming-cpu-rev...tipoo - Friday, October 5, 2012 - link
"Overall performance gains should be about 2x for GT3 (presumably with eDRAM) over HD 4000 in a high TDP part."Does this mean the regular GT3 without eDRAM cache will be twice the performance of the HD4000 and the one with the cache will be 4x? Or that the one with the cache will be 2x? In which case, what would the one with no cache perform like, with so many more EUs the first is probably correct, right?
tipoo - Friday, October 5, 2012 - link
"presumably with eDRAM"...So the GT3 in Haswel has over double the EUs of Ivy Bridge, but without the cache it doesn't even get to 2x the performance? Seems off to me, doesn't it seem like the GT3 on its own would be 2x the performance while the eDRAM cache would make for another 2x?DanNeely - Saturday, October 6, 2012 - link
It probably means that, like AMD, Intel is hitting the wall on memory bandwidth for IGPs. When it finally arrives, DDR4 will shake things up a bit; but DDR3 just isn't fast enough.