Haswell's GPU

Although Intel provided a good amount of detail on the CPU enhancements to Haswell, the graphics discussion at IDF was fairly limited. That being said, there's still some to talk about here.

Haswell builds on the same fundamental GPU architecture we saw in Ivy Bridge. We won't see a dramatic redesign/re-plumbing of the graphics hardware until Broadwell in 2014 (that one is going to be a big one).

Haswell's GPU will be available in three physical configurations: GT1, GT2 and GT3. Although Intel mentioned that the Haswell GT3 config would have twice the shader count of Haswell GT2, it was careful not to disclose the total number of EUs in any of the versions. Based on the information we have at this point, GT3 should be a 40 EU configuration while GT2 should feature 20 EUs. Intel will also be including up to one redundant EU to deal with the case where there's a defect in an EU in the array. This isn't an uncommon practice, but it does indicate just how much of the die will be dedicated to graphics in Haswell. The larger of an area the GPU covers, the greater the likelihood that you'll see unrecoverable defects in the GPU. Redundancy at the EU level is one way of mitigating that problem.

Haswell's processor graphics extends API support to DirectX 11.1, OpenCL 1.2 and OpenGL 4.0.

At the front of the graphics pipeline is a new resource streamer. The RS offloads some driver work that the CPU would normally handle and moves it to GPU hardware instead. Both AMD and NVIDIA have significant command processors so this doesn't appear to be an Intel advantage although the devil is in the (unshared) details. The point from Intel's perspective is that any amount of processing it can shift away from general purpose CPU hardware and onto the GPU can save power (CPU cores go to sleep while the RS/CS do their job).

Beyond the resource streamer, most of the fixed function graphics hardware sees a doubling of performance in Haswell.

At the shader core level, Intel separates the GPU design into two sections: slice common and sub-slice. Slice common includes the rasterizer, pixel back end and GPU L3 cache. The sub-slice includes all of the EUs, instruction caches and EUs.

In Haswell GT1 and GT2 there's a single slice common, while GT3 sees a doubling of slice common. GT3 similarly has two sub-slices, although once again Intel isn't talking specifics about EU counts or clock speeds between GT1/2/3.

The final bit of detail Intel gave out about Haswell's GPU is the texture sampler sees up to a 4x improvement in throughput over Ivy Bridge in some modes.

Now to the things that Intel didn't let loose at IDF. Although originally an option for Ivy Bridge (but higher ups at Intel killed plans for it) was a GT3 part with some form of embedded DRAM. Rumor has it that Apple was the only customer who really demanded it at the time, and Intel wasn't willing to build a SKU just for Apple.

Haswell will do what Ivy Bridge didn't. You'll see a version of Haswell with up to 128MB of embedded DRAM, with a lot of bandwidth available between it and the core. Both the CPU and GPU will be able to access this embedded DRAM, although there are obvious implications for graphics.

Overall performance gains should be about 2x for GT3 (presumably with eDRAM) over HD 4000 in a high TDP part. In Ultrabooks those gains will be limited to around 30% max given the strict power limits.

As for why Intel isn't talking about embedded DRAM on Haswell, your guess is as good as mine. The likely release timeframe for Haswell is close to June 2013, there's still tons of time between now and then. It looks like Intel still has a desire to remain quiet on some fronts.

TSX Haswell Media Engine: QuickSync the Third
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  • FunBunny2 - Tuesday, October 09, 2012 - link

    If Steve hadn't done what Apple does best (according to Steve) "steal" BSD unix, would you still be crowing? Reply
  • Magik_Breezy - Sunday, October 14, 2012 - link

    His operating system doesn't crash 7 times a day because he doesn't run OS X, I'll rephrase that, because he isn't a retard Reply
  • HisDivineOrder - Sunday, October 07, 2012 - link

    Let's not forget the obscenely high failure rates due of Macbook Pro's because they are huge, metallic, and yet refuse to have vents ruin the smooth awesomeness of their aesthetic.

    Whoops, for many it won't last more than two years, if that. Hell, if you're lucky, your battery will give out before your laptop cooks. Regardless, look up what Apple suggests and you'll get:

    Buy another one. Yours is old. ;)
    Reply
  • Magik_Breezy - Sunday, October 14, 2012 - link

    Anything delivers "solid performance" on Facebook & iWork
    Why pay $2,000 for that?
    Reply
  • random2 - Friday, October 05, 2012 - link

    I agree. admittedly I am not an apple fan and view them as people who have undergone a degree of brainwashing compounded by the need for some to keep up with the Jone's. A certain degree of mind control must be necessary to stick with a company that has had some questionable business practices as far as customer relations, dealing with product issues and denying said issues, not to mention the whole hypocritical stance by apple in regards to copyright infringement has also left a bad taste in my mouth. Reply
  • hasseb64 - Saturday, October 06, 2012 - link

    Disagree, not that much new from already published IDF reports almost 1 month ago. What is intresting is the claimed 40 EU GT3, other sources say lower amounts. Reply
  • JKflipflop98 - Saturday, October 06, 2012 - link

    I totally agree. It's articles like this that have kept me coming back for years. Keep up the good work Anand! Reply
  • tipoo - Sunday, October 07, 2012 - link

    "You can expect CPU performance to increase by around 5 - 15% at the same clock speed as Ivy Bridge. "

    That seems terribly disappointing for a tock, even IVB as a Tick managed 10% in most cases.
    Reply
  • medi01 - Tuesday, October 09, 2012 - link

    One can't be biased !@# !@#@ and a good journalist at the same time.
    One needs to be blind not to see how glass is always half empty for AMD, and half full for nVidia/Intel. F**!@#'s were shameless enough, to test 45W APU with 1000W PSU and such crap is all over the place.
    Reply
  • Paulman - Friday, October 05, 2012 - link

    As I was reading this article, about part way into the low platform power sections I suddenly had this thought: "Oh man, AMD is gonna die...!"

    I don't know if that's true for the entire microprocessor side of AMD, since they look like they're already starting to transition out of the desktop space, but I don't know if they're going to stand much of a chance if they're planning on entering the same TDP range as Haswell.

    Do you think there's a chance AMD will start focussing on designing ARM ISA cores? Or will expanding on their x86 Bobcat-type cores be enough for them?
    Reply

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