While compute functionality could technically be shoehorned into DirectX 10 GPUs such as Sandy Bridge through DirectCompute 4.x, neither Intel nor AMD's DX10 GPUs were really meant for the task, and even NVIDIA's DX10 GPUs paled in comparison to what they've achieved with their DX11 generation GPUs. As a result Ivy Bridge is the first true compute capable GPU from Intel. This marks an interesting step in the evolution of Intel's GPUs, as originally projects such as Larrabee Prime were supposed to help Intel bring together CPU and GPU computing by creating an x86 based GPU. With Larrabee Prime canceled however, that task falls to the latest rendition of Intel's GPU architecture.

With Ivy Bridge Intel will be supporting both DirectCompute 5—which is dictated by DX11—but also the more general compute focused OpenCL 1.1. Intel has backed OpenCL development for some time and currently offers an OpenCL 1.1 runtime for their CPUs, however an OpenCL runtime for Ivy Bridge will not be available at launch. As a result Ivy Bridge is limited to DirectCompute for the time being, which limits just what kind of compute performance testing we can do with Ivy Bridge.

Our first compute benchmark comes from Civilization V, which uses DirectCompute 5 to decompress textures on the fly. Civ V includes a sub-benchmark that exclusively tests the speed of their texture decompression algorithm by repeatedly decompressing the textures required for one of the game’s leader scenes. And while games that use GPU compute functionality for texture decompression are still rare, it's becoming increasingly common as it's a practical way to pack textures in the most suitable manner for shipping rather than being limited to DX texture compression.

As we alluded to in our look at Civilization V's performance in game mode, Ivy Bridge ends up being compute limited here. It's well ahead of the even more DirectCompute anemic Radeon HD 5450 here—in spite of the fact that it can't take a lead in game mode—but it's slightly trailing the GT 520, which has a similar amount of compute performance on paper. This largely confirms what we know from the specs for HD 4000: it can pack a punch in pushing pixels, but given a shader heavy scenario it's going to have a great deal of trouble keeping up with Llano and its much greater shader performance.

But with that said, Ivy Bridge is still reaching 55% of Llano's performance here, thanks to AMD's overall lackluster DirectCompute performance on their pre-7000 series GPUs. As a result Ivy Bridge versus Llano isn't nearly as lop-sided as the paper specs tell us; Ivy Bridge won't be able to keep up in most situations, but in DirectCompute it isn't necessarily a goner.

And to prove that point, we have our second compute test: the Fluid Simulation Sample in the DirectX 11 SDK. This program simulates the motion and interactions of a 16k particle fluid using a compute shader, with a choice of several different algorithms. In this case we’re using an (O)n^2 nearest neighbor method that is optimized by using shared memory to cache data.

Thanks in large part to its new dedicated L3 graphics cache, Ivy Bridge does exceptionally well here. The framerate of this test is entirely arbitrary, but what isn't is the performance relative to other GPUs; Ivy Bridge is well within the territory of budget-level dGPUs such as the GT 430, Radeon HD 5570, and for the first time is ahead of Llano, taking a lead just shy of 10%.  The fluid simulation sample is a very special case—most compute shaders won't be nearly this heavily reliant on shared memory performance—but it's the perfect showcase for Ivy Bridge's ideal performance scenario. Ultimately this is just as much a story of AMD losing due to poor DirectCompute performance as it is Intel winning due to a speedy L3 cache, but it shows what is possible. The big question now is what OpenCL performance is going to be like, since AMD's OpenCL performance doesn't have the same kind of handicaps as their DirectCompute performance.

Synthetic Performance

Moving on, we'll take a few moments to look at synthetic performance. Synthetic performance is a poor tool to rank GPUs—what really matters is the games—but by breaking down workloads into discrete tasks it can sometimes tell us things that we don't see in games.

Our first synthetic test is 3DMark Vantage’s pixel fill test. Typically this test is memory bandwidth bound as the nature of the test has the ROPs pushing as many pixels as possible with as little overhead as possible, which in turn shifts the bottleneck to memory bandwidth so long as there's enough ROP throughput in the first place.

It's interesting to note here that as DDR3 clockspeeds have crept up over time, IVB now has as much memory bandwidth as most entry-to-mainstream level video cards, where 128bit DDR3 is equally common. Or on a historical basis, at this point it's half as much bandwidth as powerhouse video cards of yesteryear such as the 256bit GDDR3 based GeForce 8800GT.

Altogether, with 29.6GB/sec of memory bandwidth available to Ivy Bridge with our DDR3-1866 memory, Ivy Bridge ends up being able to push more pxiels than Llano, more pixels than the entry-level dGPUs, and even more pixels the budget-level dGPUs such as GT 440 and Radeon HD 5570 which have just as much dedicated memory bandwidth. Or put in numbers, Ivy Bridge is pushing 42% more pixels than Sandy Bridge and 25% more pixels than the otherwise more powerful Llano. And since pixel fillrates are so memory bandwidth bound Intel's L3 cache is almost certainly once again playing a role here, however it's not clear to what extent that's the case.

Moving on, our second synthetic test is 3DMark Vantage’s texture fill test, which provides a simple FP16 texture throughput test. FP16 textures are still fairly rare, but it's a good look at worst case scenario texturing performance.

After Ivy Bridge's strong pixel fillrate performance, its texture fillrate brings us back down to earth. At this point performance is once again much closer to entry level GPUs, and also well behind Llano. Here we see that Intel's texture performance increases also exactly linearly with the increase in EUs from Sandy Bridge to Ivy Bridge, indicating that those texture units are being put to good use, but at the same time it means Ivy Bridge has a long way to go to catch Llano's texture performance, achieving only 47% of Llano's performance here. The good news for Intel here is that texture size (and thereby texel density) hasn't increased much over the past couple of years in most games, however the bad news is that we're finally starting to see that change as dGPUs get more VRAM.

Our final synthetic test is the set of settings we use with Microsoft’s Detail Tessellation sample program out of the DX11 SDK. Since IVB is the first Intel iGPU with tessellation capabilities, it will be interesting to see how well IVB does here, as IVB is going to be the de facto baseline for DX11+ games in the future. Ideally we want to have enough tessellation performance here so that tessellation can be used on a global level, allowing developers to efficiently simulate their worlds with fewer polygons while still using many polygons on the final render.

The results here are actually pretty decent. Compared to what we've seen with shader and texture performance, where Ivy Bridge is largely tied at the hip with the GT 520, at lower tessellation factors Ivy Bridge manages to clearly overcome both the GT 520 and the Radeon HD 5450. Per unit of compute performance, Intel looks to have more tessellation performance than AMD or NVIDIA, which means Intel is setting a pretty good baseline for tessellation performance. Tessellation performance at high tessellation factors does dip however, with Ivy Bridge giving up much of its performance lead over the entry-level dGPUs, but still managing to stay ahead of both of its competitors.

Intel HD 4000 Performance: Civilization V Power Consumption
POST A COMMENT

173 Comments

View All Comments

  • DanNeely - Monday, April 23, 2012 - link

    Isn't the net OC performance roughly a wash? You're losing ~10% off the top in clock speed, but getting it back by the CPU doing ~10% more per clock.

    I'm curious what the power gap for the OCed IB is vs SB. For a system kept running at full load, the stock power gap would give a decent amount of yearly savings on the utility bills. If the gap opens even more under OC it'd be a decent upgrade for anyone running CPU farms.
    Reply
  • Shadow_k - Monday, April 23, 2012 - link

    Very nice igp improvements

    An also when will anandtech do a review on the i5 3570k because igp is underclocked
    Reply
  • Ram21 - Monday, April 23, 2012 - link

    Ultraoboks Reply
  • Ram21 - Monday, April 23, 2012 - link

    Page 11 has the incorrect title or chart of Starcraft II - GPU Bench on the Dirt 3 page Reply
  • Anand Lal Shimpi - Monday, April 23, 2012 - link

    Fixed both of these, thank you! Reply
  • ltcommanderdata - Monday, April 23, 2012 - link

    I don't have a comment on this Ivy Bridge review itself since it's thorough as always from Anandtech and Ivy Bridge seems pretty much what was expected. I do want to suggest a new benchmark for the eventual OpenCL followup when Intel releases new GPU drivers. As AMD mentioned as part of heir HD7000 series launches, WinZip 16.5 has finally been released with OpenCL acceleration in collaboration with AMD. Since fluid simulations won't be a common use case for most consumers and video encoding seems better suited to fixed function hardware like QuickSync, this OpenCL accelerated file compression/decompression will probably be the first and most popular use of GPGPU by consumers. It'll be interesting to see how much of a benefit GPU acceleration brings and whether AMD's collaboration results in better performance from AMD GPUs compared to Intel and nVidia GPUs then raw hardware specs would suggest. Other interesting tests would be to see if the acceleration is more pronounced with 1x1GB compressed file versus many compressed files adding up to 1GB. How well acceleration scales with between different GPU performance classes and whether it'll be bottlenecked by PCIe bandwidth, CPU setup time, system memory transfers or more likely HDD I/O. Whether tightly coupled CPU/GPUs like Llano and Ivy Bridge gives a performance advantage compared to otherwise similar specced discrete GPUs. Whether GPU acceleration is worthwhile on older GPU generations like the AMD HD5000/6000 and nVidia 8000/9000/100/200 series which aren't as compute optimized as the latest AMD HD7000 and nVidia 400/500 series. Whether WinZip 16.5 supports the HD4000 series which is OpenCL 1.0 or whether it requires OpenCL 1.1. Does WinZip 16.5 use OpenCL to help improve performance scaling on high core count CPUs (such as 8 or more cores).

    If GPU accelerated file compression/decompression is effective hopefully Microsoft and Apple will consider adding it to their native OS .zip handler.
    Reply
  • Ryan Smith - Monday, April 23, 2012 - link

    Rest assured it's on our list of things to look at, though I haven't seen it yet. Reply
  • mgoldshteyn - Monday, April 23, 2012 - link

    The graphics engine still cannot support 10-bit per color IPS displays, as can be found on quality modern laptops from Dell and HP. That means that one is forced to get an overpriced mobile video card from ATI or NVidia to compensate, lowering the laptops power on hours by requiring an external card to be used with these displays. On non-IPS displays, one can choose to use the Intel built in graphics engine to save battery life. No such choice on high quality IPS displays since they are incompatible with the graphics engine of even Ivy Bridge. Reply
  • zaccun - Monday, April 23, 2012 - link

    The workstation class laptops you are referring to are only offered with discrete graphics cards. No other machine has a 10 bit IPS panel. There is zero sense in dell or HP offering a machine aimed at professionals doing 3d modeling/CAD/video editing/etc without also putting the graphics horsepower in the laptop to support it.

    While I personally would love the option of getting a machine with the awesome panels that those notebooks use, without also paying for the $$$$ quadro cards that pros need, neither Dell nor HP offer anything like that.
    Reply
  • Arnulf - Tuesday, April 24, 2012 - link

    Neither can you eyes distinguish 1 073 741 824 different colors so why would you care ? Reply

Log in

Don't have an account? Sign up now