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AMD A10-4600M Review: Mobile Trinity Gets Tested

The GPU Side: VLIW4 > VLIW5

While Trinity benefits from the very latest work in AMD’s processor portfolio, the APU employs a one-generation-old graphics architecture (that is to say it doesn’t use the Graphics Core Next design at the heart of Radeon HD 7000-series cards). Nevertheless, Trinity’s on-die GPU—ominously code-named Devastator--isn’t a re-hash of the old VLIW5 arrangement first seen in the Radeon HD 2900 XT either. It’s based on the more efficient VLIW4 design exclusive to the Radeon HD 6900 series.

Based on the nomenclature alone, you might assume that VLIW4 is VLIW5-minus-one, and you probably aren’t inclined to assume it’s improved. VLIW4 makes better use of available resources in today’s games, though. Let’s dig into why that’s the case.

VLIW stands for very long instruction word (describing AMD’s architecture), while the number is indicative of the quantity of ALUs in each thread processor. Due to wavefront dependencies, it’s difficult to keep all five of the ALUs in a VLIW5 thread processor engine fed. According to AMD’s analysis, modern games tend to utilize between three and four ALUs each clock cycle. VLIW4 removes the fifth and inefficient ALU, while enhancing the capabilities of the remaining four, resulting in better utilization of resources and available die space for an increased number of thread processors. VLIW4 provides better performance per mm², improved flow control, and improved GPU compute results compared to VLIW5. The newer design also accommodates improvements in the hardware tessellator, with better thread management and buffering support. For more details about the advantages of VLIW4, check out Radeon HD 6970 And 6950 Review: Is Cayman A Gator Or A Crock?.  

Now, the Devastator GPU portion of Trinity has six SIMD engines, each with four texture units and 16 thread processors. With four ALUs per thread processor, Devastator boasts a grand total of 384 ALUs and 24 texture units. Two render back ends control the output, each able to handle four full-color raster operations per clock for an aggregate 128-bit memory interface and eight ROPs.

These specifications appear quite similar to Llano’s Sumo core, the key differences being that Devastator has 16 fewer ALUs and four more texture units. But when you consider the inefficiencies of VLIW5, as many as 80 of Llano’s ALUs could be going unused at any given time. So, we expect the newer APU to outperform its predecessor in gaming and compute applications

There are a handful of other differences as well. For instance, Trinity supports three independent display outputs (four if you’re using DisplayPort to daisy chain one panel to another), while Llano is limited to two outputs and DisplayPort 1.1a. Each of the four displays accommodates its own protected high-bitrate 7.1-channel audio stream, and display grouping is also supported.

In addition, the new model includes AMD’s Video Codec Engine (VCE), fixed-function logic dedicated to H.264 encode that we haven’t been able to test on any of the company’s Radeon HD 7000-series cards because the feature was not enabled in software. We’ll be testing it for the first time later in this article, though.

  • JAYDEEJOHN
    Hope its only the beginning of much more
    Reply
  • Recently Charlie at semiaccurate (a massive amd fanboy) hinting an upcoming apple products, then I saw an article in thg that tells an upcoming mbp will using retina display... 15 inch retina will require huge gpu horsepower, my wild guess is mbp will use trinity as it's CPU.
    Reply
  • Based on this, gaming is much better than old i5, but everything else including application performance is still better on the old Sandy architecture. I'm not really sure why I would buy a Trinity other than for a casual gaming laptop. Unfortunately, budget says that my laptops have to be used for business first, play time later.
    Reply
  • beenthere
    Nice to see that Trinity and AMD have delivered the goods. I want a Trinity powered Ultrathin. Intel can stick their crap where the Sun don't shine.

    BTW, Charlie @ SemiAccurate is not an AMD fanbois IME. He just calls it like it is. Reality bites sometimes be it Nvidia, AMD or Intel's problems. Denial never changes reality. It is what it is.
    Reply
  • cleeve
    duckwithnukesWhere is the Intel HD 4000 vs. AMD Trinity comparison? Lazy reviewing at its finest.
    A10-4600M laptops will be int eh $600-$700 neighborhood, and we're still waiting for Ivy bridge Core i5 to arrive in this price range.

    We go over this. We also talk about how we'll do a follow up as soon as an appropriate product is available.

    You need to read for it to make sense.
    Reply
  • FlippyFlap, Apple doesn't use AMD and an HD4000 can power a retina display. I'm sure Apple has worked with Intel engineers to get the drivers right for retina displays which is HD4000's problem. HD4000 is still lacking in terms of driver support (one can see that from the OpenCL benches around the net where only 1/2 get acclerated on HD4000). When the drivers work right, there isn't much difference between Ivy and Trinity.
    Reply
  • I agree with Cleeve and I personally hate comparing a reference system to a selling system anyway. Review 2 actual selling systems with similar parts and that gives you the benchmark.
    Reply
  • DRosencraft
    This looks like a very nice effort from AMD. I really, really need to replace my notebook. It's a six year old Toshiba Satelite with an AMD 1.9 GHz Turion 64 X2 with intergrated X2100 graphics.... yeah. Ancient now, I know. I've been trying to figure out a sweet spot in power since my needs are kind of complex. Typically I don't need it to do much more than handle MSOffice and web surfing. But I also tend to use it for video gaming when am interesting game comes around and some work in PaintShop when I'm out of the house, or don't feel like sitting at my desktop. This may be a little closer to what I'd like. It would be nice to get a notebook that combines this with a really good discrete card (sort of like how some MacBook Pros have their dual graphics setup). Nevertheless, Trinity looks to be just about enough power and performance, but the question is price. If tradition holds, it should be a good price competitor with Intel, which is the most important part, otherwise I'd just buy a core I7 already.

    In a related question, does Trinity's details and specs lead to any conclusions about what Piledriver desktop processors will be like?
    Reply
  • neoverdugo
    So this means that AMD can kick Intel's ass in the gpu department for the moment while AMD suffers greatly in the CPU portion of the apu battle. Didn't I said before that Intel is trying to make an (proprietary) Intel only PC with no third party strings attached? We all know that there is no competition in the CPU battle when it comes to Intel. Still, i would like to see that the morons of intel to drop the price of their hardware for once and for all and drop ridiculously low end hardware out of production.
    Reply
  • dgingeri
    No WoW benchmarks this time? I was wondering if this might make a good laptop for WoW, but you guys failed me. :(
    Reply