Sign in with
Sign up | Sign in

Making Memory Performance Matter Again

AMD A8-3850 Review: Llano Rocks Entry-Level Desktops
By

Intel’s Nehalem architecture really did a number on the memory market. Not only did the company define a hard limit on the voltage its memory controller could reliably take, but the triple-channel configuration was in no way hurting for bandwidth. We had a handful of vendors hand us 2000+ MT/s kits, but even after jumping through the hoops (and screaming-high uncore voltage) required to get memory running that fast, the benefits were almost negligible.

You would think that the addition of on-die graphics to Clarkdale and Sandy Bridge would help bring memory performance back into the forefront. But it really didn’t, even with one channel shaved off the controller.

The thing is, before anyone can be made to care about integrated graphics scaling, the graphics engine has to be deemed viable. HD Graphics 2000—the implementation on most of Intel’s Sandy Bridge-based processors—is a baby-step better than Clarkdale’s dismal showing. Only now does Intel see the value in arming more mainstream processors with HD Graphics 3000, the way it should have at launch, which is why we finally have chips like the Core i3-2105 to test.

But as we’ve seen, the Radeon HD 6550D core at the heart of AMD’s A8-3850 is actually a respectable performer. So much so, in fact, that it’s hamstrung by a lack of memory bandwidth at 1333 MT/s, even in a dual-channel config.

So, let’s start by exploring available bandwidth from DDR3-800 to -1866 using SiSoftware’s Sandra 2011. We used Kingston’s KHX2133C9AD3T1K2/4GX kit to maximize scalability. And while we were able to retain CAS 7 timings through DDR3-1333, anything higher required CAS 8 for stability.

It’s possible to basically double bandwidth from 800 MT/s to 1866 MT/s, and you can see the returns starting to fall off as you hit higher signaling speed and give up timing for higher clocks. Good to know, though. Now let’s look at application performance and see how it corresponds.

In Metro 2033, the move from DDR3-800 to DDR3-1600 nearly doubles performance, scaling almost perfectly with the bandwidth improvement measured in Sandra 2011. That’s a heavily graphics-bound benchmark, and it’s only at DDR3-1866 where the returns are no longer worth spending more on faster memory.

Call of Duty is known to scale well based on platform capabilities, not taxing graphics cards much at all. But again we see a doubling of performance when you downshift from DDR3-800 to DDR3-1600. There’s clearly a bump in the scaling story when we’re forced to use CAS 8 timings, but it really gets bad at DDR3-1866 when keeping the system stable requires relaxing tRCD to 9 and performance slips back the other way. If we could get our hands on some good DDR3-1600 CAS 7, that’d be ideal.

AMD’s processor architecture is less constrained by memory performance than the graphics engine. However, you still see significant gains moving from DDR3-800 to DDR3-1333. Beyond that, it’s really not worth paying extra for higher-end memory.

A transcoding job sees even less gain from fast memory than a file compression workload. You’ll see marginal speed-ups from DDR3-800 to DDR3-1333, but the amount of time you shave from an app like MainConcept is minimal.

Buy Fast/Low-Latency Memory

Despite marginal gains in application performance, the bottom line here is simple: if you want to get the best horsepower out of a Llano-based APU, that graphics engine needs to breathe. Memory able to support a high data rate at low latencies is absolutely imperative for the best possible frame rates in games.

Don’t sweat DDR3-1866 if it means CAS 8 or 9 timings. Aggressively-tuned DDR3-1600 looks to be the sweet spot. We had luck getting our Kingston HyperX DDR3-2133 kit running at DDR3-1600 CAS 7 on a couple of boards, but not the ASRock board we eventually used for testing. Even at CAS 8, though, performance was superb.

Ask a Category Expert

Create a new thread in the Reviews comments forum about this subject

Example: Notebook, Android, SSD hard drive

Display all 148 comments.
This thread is closed for comments
Top Comments
  • 17 Hide
    Yuka , June 30, 2011 5:54 AM
    stardude82That's about all the sense it makes then.


    Actually Llano on the Desktop is (IMO) aimed at HTPC a 100% and, off course, notebooks.

    I would really, really like to see more media features with the Llano parts you guys have if it can be done 8)

    Great article as usual!

    Cheers!
  • 16 Hide
    Anonymous , June 30, 2011 3:23 PM
    Heh, I love these comments - for $150 more than a $135 AMD CPU you can get a better Intel CPU and AMD GPU!

    No shit, really? I wouldn't have thought so, it's just twice the price!
  • 16 Hide
    cknobman , June 30, 2011 2:37 PM
    Good lord reading the comments some of you people are really dense. Do you not understand the target market for these and can take the review in context????? Not everything should be looked at as though you are a custom power cpu/game builder.

    Great review Chris. For the target market AMD is doing a pretty good job here with an old CPU architecture and once they pair this with Bulldozer they should have a killer product.
Other Comments
  • 14 Hide
    whatisupthere , June 30, 2011 4:06 AM
    Great review! Thanks Toms
  • 13 Hide
    Tamz_msc , June 30, 2011 4:21 AM
    Another win for AMD!
  • 1 Hide
    SteelCity1981 , June 30, 2011 4:24 AM
    So then what's the point of getting the Turbo Core versions when they are going to be Turbo Clocked slower then the none Turbo Clocked versions...
  • 15 Hide
    cangelini , June 30, 2011 4:29 AM
    SteelCity1981So then what's the point of getting the Turbo Core versions when they are going to be Turbo Clocked slower then the none Turbo Clocked versions...


    They don't want you to see better performance from a cheaper APU in single-threaded apps by pushing Turbo Core further ;-)
  • 1 Hide
    Known2Bone , June 30, 2011 4:35 AM
    i really wanted see some amazing gains in the content creation department what with all that gpu power on chip... oh well games are fun too!
  • 12 Hide
    ivan_chess , June 30, 2011 4:41 AM
    I think this would be good for a young kid's PC. It would be enough to run educational software and a web browser. When he grows up to be a gamer it would be time to replace the whole machine anyway.
  • 5 Hide
    DjEaZy , June 30, 2011 4:52 AM
    ... it's may be not the greatest APU for desktop... but it will be a powerful thingy in a laptop... the review was nice... but in the gaming department... would be nice to see a standard 15,x'' laptop resolution tests @ 1366x768... or something like that...
  • 3 Hide
    Mathos , June 30, 2011 5:00 AM
    Actually if you want good DDR3 1600 with aggressive timings, the Ripjaws X series memory that I have does DDR3 1600 at 7-8-7-24 at 1.5v, not all that expensive when it comes down to it either.
  • -2 Hide
    Stardude82 , June 30, 2011 5:04 AM
    This makes little sense. An Athlon II X3 445 ($75) and a HD 5570 ($60, on a good day you can get a 5670 for the same price) would provide better performance for the same price ($135) and not have to worry about the RAM you use.

    So is AM3+ going to be retired in favor of FM1 in the near future? Why are there chipset at all? Why isn't everything SOC by now?

    Otherwise this is a very good CPU. If AMD has used 1 MB level 2 caches in their quads when they came out with the Deneb Propus die, they would be much more competitive.
  • 9 Hide
    crisan_tiberiu , June 30, 2011 5:37 AM
    stardude82This makes little sense. An Athlon II X3 445 ($75) and a HD 5570 ($60, on a good day you can get a 5670 for the same price) would provide better performance for the same price ($135) and not have to worry about the RAM you use.

    what about power consumption?
  • -7 Hide
    Stardude82 , June 30, 2011 5:46 AM
    crisan_tiberiuwhat about power consumption?

    That's about all the sense it makes then, for mobile and all-in-one units, but for cheap desktops... eh.
  • 17 Hide
    Yuka , June 30, 2011 5:54 AM
    stardude82That's about all the sense it makes then.


    Actually Llano on the Desktop is (IMO) aimed at HTPC a 100% and, off course, notebooks.

    I would really, really like to see more media features with the Llano parts you guys have if it can be done 8)

    Great article as usual!

    Cheers!
  • -4 Hide
    jdwii , June 30, 2011 5:54 AM
    not bad but can you overclock the graphics core
  • 10 Hide
    fictionforthetame , June 30, 2011 6:11 AM
    I completely agree with Yuka and was thinking the whole way through how amazing these would be (especially the low TDP versions) in a HTPC.
  • 2 Hide
    RazberyBandit , June 30, 2011 6:17 AM
    In regards to dual graphics, the only game that it seemed to work on was WoW Cataclysm. What was the cause, drivers? CAPS?

    And I think you guys may have gotten the min and avg FPS scores for the CoD:MW benchmark backwards... How can the min be higher than the average? Maybe you were actually comparing No AA to 4x AA or something, not min and avg FPS?
  • 3 Hide
    Nintendork , June 30, 2011 6:30 AM
    This review need IGP OC. The Llano GPU overclocks like hell.

    600Mhz to 840/900Mhz? No problem at all.
  • 3 Hide
    frozenlead , June 30, 2011 6:34 AM
    On the COD graphs, the minimum and average FPS bars have to be switched...it's impossible to have a "minimum" data point greater than the average.
  • 9 Hide
    ChiefTexas_82 , June 30, 2011 6:38 AM
    Since when does a 100W CPU and a 6530 need a 850W power supply???

    Anyway, The real show should be bulldozer-based APU's. If they could just get the graphics up to a 5750 level...
  • 7 Hide
    ChromeTusk , June 30, 2011 6:45 AM
    Great article. This really helps me out since I need to replace 2 laptops in the near future.
    As for a higher end desktop, I am waiting for BD and how it affects the market. That will determine which parts I keep and which parts get put into an HTPC.
  • -4 Hide
    fstrthnu , June 30, 2011 7:08 AM
    Definitely looks like a stopgap measure, a product with good execution but no market. Basically, the only people who will buy this are casual/lazy PC gamers - the serious guys would come to sites like this very one to find out that they can get way more for their money than buying Llano. Thing is, at this price point, most people don't even care about games. Like I said on a previous post, any serious, smart PC gamer will build their own or look higher in terms of pricing to get a genuinely strong system.
Display more comments