The GPU

While the Llano CPU cores may be in need of a major overhaul, Llano's GPU is as new as it gets. Technically based off of AMD's Redwood core (Radeon HD 5570) with some enhancements, Llano's GPU is codenamed Sumo.

The DX11 GPU features five SIMD arrays, each with 80 cores for a total of 400 shader processors. Similar to the updates we saw with this year's Northern Islands GPUs, Sumo does add UVD3 support to the Redwood architecture. Of course since Sumo shares the same die as the Llano CPU cores it is built on GlobalFoundries' 32nm process, making this the first AMD GPU fabbed at GlobalFoundries and not TSMC.

For everything behind the memory controller Sumo is virtually identical to Redwood. Where Sumo differs is in its memory interface. Although Llano is AMD's first performance oriented APU, it's still constrained by a 128-bit wide DDR3 memory interface. That dual-channel memory interface has to be shared by all four Llano cores as well as the Sumo GPU and as a result, arbitration is very important.

AMD shared a few choice details about the Llano memory controller architecture. To begin, AMD guarantees more than 30GB/s of bandwidth is available between the GPU and the memory controller—in other words, the path from GPU to the memory controller won't become a bottleneck. The GPU/memory controller link (i.e. within the APU die) can apparently scale up to as much as 50GB/s to support future APUs with even faster memory interfaces. Note that unlike previous integrated graphics solutions, there is no support for dedicated external memory—this is a pure shared memory architecture.

Second, and most importantly, AMD can dynamically prioritize memory bandwidth between the CPU and GPU. In most cases, when both processors are heavily consuming data, the GPU is given priority over the CPU. Given today's workloads, prioritizing the GPU for memory accesses makes sense when it's running full tilt. The chances of you stressing all four CPU cores and running at full GPU memory bandwidth requirements are pretty slim today.

With 400 shader processors behind a shared 128-bit DDR3 memory interface, the upper bound for Sumo performance is the Radeon HD 5570. In practice, you should expect performance to be noticeably lower since the GPU does have to share its precious memory bandwidth with up to four x86 CPU cores.

The mobile version of Llano supports up to DDR3-1600 while the desktop parts can run at up to DDR3-1866. Maximum memory capacities are 32GB and 64GB for notebooks and desktops, respectively.

Llano has a total of 24 PCIe Gen 2 lanes at its disposal. Sixteen of those lanes can be used for external graphics. Four of the lanes can be used for devices that need low latency/high bandwidth access to the APU itself (e.g. Gigabit ethernet). The remaining four lanes are used to connect the APU to its sole partner in crime: the Fusion Controller Hub.

AMD is particularly proud of the display output configurations supported by Llano. The possible combinations are listed below:

Chipsets

AMD will offer two Fusion Controller Hubs (FCHs) as options for Llano: A70M and A60M. The only difference between the two is in their support for USB 3.0; the A70M has four USB 3.0 ports while the A60M has none.

Both FCHs support 6Gbps SATA and perform just as well as AMD's 8-series chipset (or Intel's Z68) with a high performance SSD. USB 3.0 performance is also comparable to 3rd party solutions we've seen deployed on motherboards already.

The Llano A-Series APU Power Gating & Turbo Core
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  • JarredWalton - Tuesday, June 14, 2011 - link

    The only way to make sure that Intel's current processors aren't at the top of most charts is to leave them out, particularly on notebooks. If we only look at IGP/fGPU, AMD comes out on top of graphics charts, but is that fair to NVIDIA's Optimus technology that allows dynamic switching between IGP and dGPU in a fraction of a second? The overall tone of this article (apart from the CrossFire section) is positive, but still people look at the charts and freak out because we didn't manipulate data to make Llano look even better. It's not bad, but it's certainly not without flaws. Reply
  • kevith - Tuesday, June 14, 2011 - link

    Oh too bad.

    I would like to use a laptop for music production with Nuendo and Win 7.

    It actually reqires a little more graphics-musclle than you might think to run an app like Nuendo.

    And,up to now, it has not been possible to get both a powerful CPU and GPU in the same machine for the money I have.

    So now the fGPU is powerful enough, that's great. But it seems, that the CPU-part of these APU's are too weak.

    Øv...
    Reply
  • krumme - Tuesday, June 14, 2011 - link

    Øhhh

    Just make sure your computer have 1Gb ram and win xp sp2, Nuendo even runs on single core 2Ghz whatever old shit.
    I would save the money and buy a e350.
    Heck you could even buy an Atom 510, acording to Anandtech, its just as fast as e350 for the cpu side.

    When i think about it. Just do that.
    Reply
  • ET - Tuesday, June 14, 2011 - link

    As madseven7 commented correctly, this isn't the fastest Llano CPU. There are 45W parts which perform better. They will have less battery life, but a significant increase in core speed. If you're interested in Llano you might want to wait until they get reviewed. Reply
  • JarredWalton - Tuesday, June 14, 2011 - link

    I suspect the 45W Llano parts will only have less battery life if you're specifically doing CPU/GPU intensive tasks. At idle, SNB and Llano should both bottom out at similar levels. For example, if you have a 2630QM and a 2820QM doing nothing, they both run at a very low clock and voltage. We'll test any other Llano chips we can get and report our findings, but other factors (BIOS and firmware optimizations) will generally be more important than whether the TDP is 35W or 45W, at least for our particular battery life tests. Reply
  • Shadowmaster625 - Tuesday, June 14, 2011 - link

    I dont get the Cinebench single threaded results. An N660 is about the same as a desktop X2 250/255 on that benchmark. Yet this A83500M scores only 61% of what an X2 250 does. That would seem to indicate that it is only running at 1.8GHz during that single threaded test. Why so low with 3 idle cores? It should be running at 2.5GHz and scoring 2500, or just neck and neck with a P520. Turbo is clearly not working anywhere near as well as it should be. Reply
  • krumme - Tuesday, June 14, 2011 - link

    Well this is AMD business at work. They are in a constant learning process and have been for the last 40 years.

    Next time they might consider the following:

    1. Dont send some half baked prototypes to the reviewers. Wait fx. 3 more weeks. This is just old Jerry Sanders style.

    2. Consider not sending stuff to Anandtech. As anandtech lives from backlinking also, the site needs the new product. And AMD, - and for the sake of the consumers right decisions, can live without 3 similar i7 plus high end discrete gfx, at 1.200 usd at the top of each chart. If AMD dont understand they have other interest than Anandtech - its business for all - they cannot serve their own interest. And its about time they start to earn their own money. They are competing against Otellini not some stupid schoolboy.
    Reply
  • JarredWalton - Tuesday, June 14, 2011 - link

    Thanks, krumme; always a helpful response. Lenovo has taken this to heart, I'm sure you'll be happy to know, and is not sending any review samples our way. Amazingly, we're still able to survive. And FWIW, if AMD hadn't sent us anything, we'd have had more content earlier through other sources. The only way they can get us to abide by NDAs is by actually working with us. Reply
  • krumme - Tuesday, June 14, 2011 - link

    Well thank you Jarred. That was an helpfull answer! that explains a lot.

    I hope AMD gives you attention and work with you in the future, its in all your readers interest.

    That means AMD giving you priority, broad access to the right people and more time to do the reviews.
    Reply
  • JarredWalton - Tuesday, June 14, 2011 - link

    This is something I discussed with AMD numerous times, and it's one of the reasons we want a utility that will show us true CPU clock speeds in real time. Unfortunately, they don't have anything they're willing to share with us right now. They said they have test units where they can monitor this stuff, but it requires special BIOS hooks and those are not present in our preview samples. In theory, Turbo Core should allow the single-threaded Cinebench result to run up to 60% faster than non-Turbo. Of course, we can't even disable Turbo Core either, so we don't know how much TC is actually helping.

    P920 is clocked 6.7% higher than A8-3500M, but 3500M has twice the L2 cache and some other enhancements. With 3500M coming in 17% faster than P920, that would suggest that 3500M averages around 1900MHz, but that could mean it runs at 2.4GHz for a bit and then 1.5GHz for a bit, or somewhere in between.

    Given the way AMD does Turbo Core (monitoring instruction workloads and their relative power requirements), I think that at least right now, it's not being as aggressive as Intel's Turbo Boost. It feels more like Bloomfield and Arrandale turbo, where you got an extra 2-4 bins, rather than Sandy Bridge where you can get an extra 5-10 bins. Hopefully we'll see refinements with Turbo Core over the coming months and years.
    Reply

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