The AMD A8-3850 Fusion APU is the current top-end desktop Llano chip, and is a bit a doozy.
AMD has released Fusion APUs before now. with its lower-end Brazos chips (Zacate and Onlatio) paving ihe way for this far more serious, perf ormance part. Both Brazos chips, though. were designed specifically for the ultrathin notebook market, coming in at 9W for the Ontario chips and 18W for the Zacate APUs. They did make appearances in the mini-mobo segment of the desktop market but didn't really take off.
Next, Intel stole the match on AMD in terms of performance parts, with its Sandy Bridge lineup, integrating its HD 3000 and HD 2000 CPUs in with its 2nd Generation Core series CPUs. Intel's focus was on powerful CPU parts with an improved GPU component integrated into the chip. AMD's focus, however, is far more based upon jamming discrete class graphics into the same component as decent quad-core processing part.
When we reviewed the new Llano laptop in the last issue we were astounded by just how much graphical grunt AMD has managed to pack into its latest mobile APU, offering legitimate gaming performance out of a laptop that's capable of going for eight hours and costs around £600. On the desktop it's looking even more impressive.
The CPU component of the mobile part looked pretty weak at 1.5GHz. but on the desktop it's a far more serious setup, and for a far more reasonable price.
Around £400 for a proper DirectX II gaming machine, with the top-end A8-3850 Fusion APU, capable of playable frame rates on a 22-inch panel? Sign us up, Mr AMD....
Jam packed
The first thing to talk about is what has actually been crammed onto this 228mm! slab of silicon. Sitting inside that unassuming package is a fully-featured quad-core CPU. based on the Stars architecture that made up the Phenom processors, a discrete-class DirectX II GPU and a full Northbridge too.
Sadly, though, we re not really talking about a full Phenom II CPU The optimised Stars architecture in the AMD A8-3850 Fusion APU actually has more in common with the Athlon II processors.
The missing ingredient is that L3 cache; the Llano Lynx APUs only come with 1MB of L2 cache per core, making a total of 4MB for the numerically challenged out there.
Both the Phenom II and Athlon II carry only 512KB per core of L2 cache, but the Phenom II supplements that with a full 6MB of L3 cache shared across the CPU cores.
This AMD A8-3850 Fusion APU comes with a stock speed of 2.9GHz, making it roughly analogous with the Athlon IIX4 635 processor. It's a full-fat quad-core, though lacks the Turbo Core functionality of the lower-end Llano Lynx Fusion APUs. Still, at 2.9GHz across all cores it's plenty fast enough for general computational tasks.
It s also capable ot utilising much faster memory than its Athlon II and Phenom II brethren. It maxes out with dual channel DDR3runningat 1.866MHz. and with the new integrated GPU in this APU that faster memory makes a significant difference, but we'll come to that later.
There will be lower-end SKUs of these Llano Fusion APUs. in both A8 and A6 nomenclatures. The A8 APUs come with the top HD 6550D AMD Radeon GPU and the A6 has the weaker HD 6530D. There will be two lower-powered (65W) variations in both A8 and A6 trim with lower cock speeds but with Turbo Core enabled to take up a bit of the slack.
Graphics chip
On the GPU side, the AMD Radeon HD 6550D is a proper DirectX, discrete-class graphics chip. This top graphics part of the A8 series APUs comes with 400 unified shaders -now called Radeon Cores in response to NVIDIA'sCUDA Cores, 20 texture units and eight ROPs, running at 600MHz for good measure.
In terms ot relative discrete cards, you're lookingat the AMD Radeon HD 5570 levels of performance from an integrated graphics solution.
The lower-end AMD Radeon HD 6530D will then be fairly closely specced to the Radeon HD 5550. with 320 shaders, 16 texture units and eight ROPs.
If you want to compare this with the Sandy Bridge top-end graphics part, the HD 3000 (which is only available in the unlocked K-series chips), it's night and day.
The Intel part is only DirectX 10.1 compatible and is only capable of delivering around 125 GFLOPS of graphical processing power at most. The Radeon HD 6550D in this A8-3850 Fusion APU by contrast tops out at 480 GFL0PS.
To go along with the brand new APU. AMD has also created a brand new desktop motherboard, with a whole new socket. The socket is the new 905 pin FM1 and the chipset is the A-series.
The top-end chipset is the A75 with the lower-end A55 coming behind it. The only real difference is in the interfaces on of fer with the more expensive part.
On the A75 you have both native 6Gb/s SATA interfaces and USB 3.0 connectivity. The USB 3.0 controller offers four sockets on the A75 boards and a full spread of six SATA 6Gb/s ports.
The A55, on the other hand, is settling in the I/O dark ages with plain ol' SATA 3Gb/s and USB 2.0. But for a budget offering you're unlikely to be missing out on those pricier interfaces too much.
Though the ASS boards are unlikely to have the overclocking chops of their more expensive A75 brethren, they will offer incredibly competitive pricing.
Full-fat cores
The only real disappointment with the mobile version of Llano, Sabine, was the weakness of the actual CPU component. In this desktop Lynx variant though, you've got full, quad-core performance.
In terms of price-point it's the Intel Core i3 2100 that's squaring up against this top-end Llano at the £100 mark, and it's a comprehensive win for the AMD chip across the board.
The only place the Sandy Bridge chip can take a win is in memory bandwidth, and only then by a relatively small amount. In CPU intensive tests, x264 HD video encodingandCinebench 3D rendering tests, the full four cores of the AMD APU put the dual-core, hyper threaded Core i3 to shame.
And you can forget about overclocking the Intel chip too. Well, you can up the clocks of the integrated GPU but really, what's the point? The locked-down Sandy Bridge chips won't budge an inch, but this AMD A8-3850 has got some serious overclocking chops to it.
It starts off at 2.9GHz and we managed to push it to 3.7GHz without breaking a sweat. That puts it well ahead of the Core i5 2500T, a proper quad-core Sandy Bridge CPU, albeit a low-power 45 W version.
That's a more impressive overclocking performance than we've seen from an AMD processor in a long time. The multipliers are locked down on these APUs (though the motherboard's BIOS and benching applications mistakenly reported otherwise) but the base clock of the chips will move.
What's more, they'll push up the performance of the GPU component of the chip at the same time as the CPU and RAM parts. That means all-round performance goes up with the overclock.
Graphic prowess
The key component of the Llano Lynx Fusion APUs. though, is their graphical prowess and in that, the integrated graphics do not disappoint.
The chip alone, paired up with an A75 board, will happily play the latest 3D games at quite playable frame rates, even if that is on more modest settings at 1680x1050 resolutions.
Surprisingly, you can get pretty close to playable at HD1080p resolutions on a few titles.
One of the really interesting things, both for us and the DRAM manufacturers struggling with margins, is just how much difference good memory paired up with your AMD A8-3850 Fusion APU makes. In some cases going from 1,333MHz DDR3 up to the same 4GB sticks running at 1,866MHz made for a 5f ps increase in games.
The difference was even more pronounced with AMD Dual Graphics enabled. That's the new name for the AMD Fusion APU s hybrid CrossFire capabilities.
Essentially you can now pair up an AMD discrete card with the onboard graphics of the APU for a serious graphical boost. And the extra memory speed can add on even more than the 5fps we saw in the onboard graphics.
There's little point pairing the A8-3850 up with a serious graphics card, like the AMD Radeon HD 6950. though, but a modest GPU like the £75 Radeon HD 6670 is well worth a look. On its own it's not a bad card but with the Dual Graphics function enabled its performance was boosted by anything from 33 per cent to 46 per cent.
Finally Fusion
We have to admit to being mildly stunned by the performance of the AMD A8-3850. It's no high-performance hero, but in terms of bang for buck there's little else that can come close to it.
The fact that both the chip and motherboard can be picked up for around £200 all-in is pretty impressive.
Factor in a cheapo discrete AMD GPU. some decent RAM and a low-power PSU (you'll only really need 300-400W) and you've got yourself a decent DirectX 11 gaming machine for less than £400.
It's not all good news, though. As ever the early adopters are going to face a possibly frustrating time until the drivers properly mature.
Over the course of the review process new BIOS versions have appeared for a number of boards, though the Asus FlA75-V Pro has remained pretty stable all along, offering the best overclock of the two boards we've used so far.
We found there was visual artefacting both in-game and occasionally in Windows. We also had a few problems trying to use discrete cards on their own without the hybrid CrossFire functionality enabled.
On one occasion the USB ports completely froze, stopping me from using a mouse at all, even after a reboot or seven.
On the whole, though, performance has been solid. In raw graphical grunt terms. Heaven 2.5 is a great indicator of power, and in that pairing of Radeon HD 6670 and AMD A8-3850 you've got something that's getting on par with a GTX 460.
Unfortunately, though, that doesn't necessarily translate into real-world gaming performance. Because the GPU is so interlinked with the CPU when it comes to graphically taxing tasks, it seems to lessen the power of the processor component. This is evidenced in Shogun 2 s CPU benchmark, which drops significantly when you put in a discrete card for Dual Graphics.
In normal mode you're looking at 19fps, but that drops down to I4FP5 when a second GPU is dropped into the mix. This is probably why. despite impressive raw graphical processing power giving decent Heaven scores, that doesn't translate into the same level of performance in games benches that require both GPU and CPU power at the same time.
We're also a little concerned about the lifespan of the platform itself. At Computex this year we were shown the Trinity APU. next year's Fusion offering that will incorporate discrete-class DX11 graphics with a Bulldozer CPU in the mix. And speaking with the likes of MSI and Gigabyte, they seem pretty sure that's going to need a whole new socket again.
So you're not future-proofing yourself with this Fusion APU. as the FM1 socket is unlikely to last anywhere near as long as AM3has.
Still, for what it is it's a darned impressive offering. And the chance to have such a powerful little PC for such a small outlay is rather enticing.
Testing
The AMDA8-3850 Fusion APU goes straight up against the Core i3 2100 and soundly whips it in all tests. This isa segment where AMD really has got a tangible edge over Intel for a change. The CPU performance, and overclocking capabilities especially, show up just how good it is in both raw computational terms as well as on the graphical side.
Our issue with the mobile Llano was the CPU component and with that being a real non-issue on the desktop Lynx, this is an excellent new platform for AMD. Impressive.
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