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AMD A8-7600 Kaveri APU Review - HSA Arrives

Author: Ryan Shrout
Subject: Processors
Manufacturer: AMD

Kaveri Tech, Continued

The Buses

AMD did not talk about a lot of the internal plumbing with Kaveri.  We were able to glean a minimal amount of information, but I stress that it is minimal.

The Onion (coherent) bus and Garlic (non-coherent) bus were both improved over the previous generation of products.  AMD did not go into great detail other than to say that bandwidth is improved.  Low level changes had to be made to these busses to support HSA, but again details were left out.  The memory controller was also massively reworked to support the shared memory architecture as well as provide more performance and efficiency when dealing with such loads.  It looks as though it also supports memory speeds up to DDR3-2400 levels right out of the box.

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Kaveri now officially supports PCI-E 3.0.  This feature was actually designed into Trinity/Richland, but AMD did not spend the time or money to certify their unit for that specification.  When I spoke with them last year about this they simply said it was not really worth it considering the marketplace they were focusing on.  To a great degree, this is likely true.  Trinity/Richland were far less likely to need the high speed interconnects that PCI-E 3.0 offered when it came to RAID controllers, PCI-E SSDs, or graphics cards.  Now that it is 2014, AMD has marked off the PCI-E 3.0 checkbox for their OEM partners and have opened the door for future, higher performing FX processors utilizing the FM2+ socket infrastructure.

                                                       

GCN in Kaveri

Graphics Core Next is the name of the next generation graphics architecture from AMD that was first introduced in early 2012 with the HD 7000 series of parts.  This was designed from the outset to be very efficient and highly programmable.  It also turned out to be very powerful as well.  The GCN portions included in Kaveri are nearly identical to those in the latest “Hawaii” based R9 290 graphics cards.

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Each GCN compute core features 4 x 16 wide vector units, a single scalar unit, plenty of cache, associated texture and texture store units, as well as the scheduler.  A total of 128 flops/clock can be achieved with each compute core, so that adds up rather quickly when there are multiple compute cores running at 720 MHz.  The big improvement is the addition of the shared, coherent unified memory feature that is the foundation of HSA.

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A total of two RBEs are included in Kaveri, which gives it a fairly decent pixel fill rate as compared to previous integrated parts.  This gives a total of 8 color ROPs and 32 stencil/Z ROPs.  I believe this is double that of previous products from AMD and Intel.

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Kaveri also supports Mantle.  This should be a nice boost in overall performance in games that adopt Mantle.  While Battlefield 4 will support Mantle “soon”, initial results showed approximately a 45% increase in frames per second from the standard Direct3D version to Mantle.  We also saw a few other native Mantle implementations that produced impressive results in performance due to the smaller amount of draw calls in complex situations.

 

Accelerators

APUs are seemingly chock full of accelerators.  These are individual units which are aimed at accelerating specific workloads.  It is far more efficient in these cases to design and implement an accelerator than to utilize the multi-core CPU or the GCN architecture to handle that workload.  This saves on power to a very great degree, all the while minimizing the die footprint of such a unit.

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Kaveri includes a very significant and new accelerator with their TrueAudio unit.  This unit contains multiple DSPs to accelerate certain audio features to improve sound quality and 3D immersion.  A handful of games will be coming out in 1H 2014 that will natively support TrueAudio.  If I were to characterize this part, I would say that it is very similar to what Aureal tried to accomplish with their A3D 2.0 implementation.  It is a step above what Creative has done with their latest EAX 5.0 based specification as well.  The real kicker here is that even though Aureal won the lawsuit brought against them by Creative, they spent so much in legal fees that it essentially bankrupted the company.  Creative then swooped in and bought their IP.  Then they sat on it and did absolutely nothing while relying on EAX to push good 3D audio to users.  That was an absolute failure.  AMD is trying to make 3D audio relevant again by introducing their TrueAudio unit.  Having this native to every Kaveri APU shipped will likely help push the specification and support further than if they released a standalone sound card embracing that functionality.

TrueAudio has uses outside of gaming applications.  Nuance is developing a noise reduction addition to their software that will utilize the TrueAudio DSP to accelerate operations for them.  This unit apparently is quite programmable and can be used for a variety of applications.

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Video playback and encoding are the two primary accelerators that have been included in APUs since day one.  The VCE 2 (video coding engine) is a highly upgraded unit as compared to VCE 1.  We can see in the slide below the changes between the two.

UVD 4 is the latest iteration of the Unified Video Decoder that was introduced many generations ago with AMD graphics cards.  The only improvement this sees is improved error resiliency.  When something is poorly encoded and contains errors, the UVD unit will not lock up and continue to show the last good frame while audio keeps moving forward.  The corrupted frame will be skipped and the video will move forward in sync with audio.

AMD does not have a H.265 decoder yet, but it will be supported through the GCN units.  This does expend more power than a more focused accelerator, but those hard coded accelerated units do take time to design and implement.  The flexibility of the GCN architecture allows it to do work such as H.265 decode without maxing out the CPUs to keep up with the workload.

 

HSA

Kaveri finally fulfills the promise of a true Heterogeneous System Architecture.  The shared memory space and addressing (hUMA), the ability for the GCN units to handle and assign threads as needed (hQ), and a growing software and programming ecosystem that can take advantage of the potential horsepower offered by this APU are working together to maximize the potential of this architecture.

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Code complexity with HSA will diminish significantly.  The use of shared memory and pointers allows the CPU and GPU to access memory without having to do copies from CPU memory to GPU memory and vice versa.  Programming tools are also either available or are being developed to support HSA so that programmers do not have to veer too far away from what they are comfortable with.  Java is the big target for AMD right now due to how many current applications are based off of that language.  They are working closely with Oracle to make sure that Java supports HSA at a very low level.  This past year Oracle joined up with the HSA Foundation.

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The flexibility of HSA was also mentioned above.  New codecs such as H.265/HEVC are not supported with current accelerators, but can be accelerated through OpenCL.  This will be true for other upcoming standards that do not yet have accelerators designed for them, or would run more efficiently on massively parallel units rather than multi-core CPUs.

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HSA is supported through software like OpenCL or C++ AMP, but some of the low level OS routines will not catch up to HSA for a while.  Linux will be receiving such updates first, but it will still be a couple of years down the road after HSA is officially ratified by the Foundation.

 

Kaveri: A Leap

We have been learning about Kaveri for years now.  Few of the details have been hidden to us, and certainly not for long.  Processor Forums, editor’s days, leaks, and investor meetings have taught us a lot about what AMD wants to do with their APUs.  Their goals are pretty lofty, but there is a lot of momentum swinging towards heterogeneous systems.  ARM is pushing that way, NVIDIA has a big stake in GPGPU, and even Intel is pushing massively parallel computing (though in a different way).

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Kaveri is a complex and potentially groundbreaking part.  One of the really big strengths of the chip is that a user does not lose the performance or functionality of the graphics portion when using a separate video card.  This could potentially have a big impact on applications which can leverage that piece of silicon.  Think of games with lots of AI and physics computations being done on the APU while the graphics card handles only the tessellation, geometry, vertex, and pixel shading.  AI and physics on an APU with shared memory is far more efficient than if running on a standalone card with its own memory.  Things like collision and interaction will be faster and more organic because a program can utilize the same memory space for the CPU and GPU portions of the APU.

Ryan now takes over with the hard numbers on this APU and we get to hear his impressions of the architecture after testing it for the past few days.

January 14, 2014 | 08:56 AM - Posted by TinkerToyTech

"Now that it is 2014, AMD has marked off the PCI-E 3.0 checkbox for their OEM partners and have opened the door for future, higher performing FX processors utilizing the FM2+ socket infrastructure."

Editor - should this be FM3+ ??

January 14, 2014 | 09:38 AM - Posted by Josh Walrath

Not that we know of.  FM2+ is what Kaveri is based on, and it supports PCI-E 3.0.  That socket should be around a long time.

January 15, 2014 | 08:35 AM - Posted by Prodeous

I think the issue was when reading "higher performing FX processors utilizing the FM2+ socket infrastructure."

First thing comes to mind is the FX-xxxx series, not the Axx-xxxx series. hence the reference to AM3+. maybe change "FX" to "steamroller" or some other reference outside of "FX"?

January 15, 2014 | 08:37 AM - Posted by Prodeous

well it seems the person was refering to FM3+ not AM3+ socket.. my bad. got confused :P

January 15, 2014 | 08:49 AM - Posted by Josh Walrath

Sources at AMD have stated that FX branded processors will be back, but AM3 is a dead end.  These things point to AMD eventually releasing a FX processor on FM2+.  Now, this FX processor will be a APU and not the traditional FX products we have seen so far.

January 14, 2014 | 09:30 AM - Posted by AMDbumlover (not verified)

why are you the only reviewer who didnt get the a10? also what about comparisons with iris pro, is that still in the works?

January 14, 2014 | 11:52 AM - Posted by renz (not verified)

TR doesn't get A10 either

January 14, 2014 | 03:42 PM - Posted by Ryan Shrout

We definitely were not the only ones to NOT get an A10 part, but we were short on time after CES to go out and source one from a different place, that's for sure.  

January 14, 2014 | 09:44 AM - Posted by gamerk2 (not verified)

CPU wise, not much of an upgrade. Kaveri is sill relegated to low end PC's and laptops.

January 14, 2014 | 10:14 AM - Posted by Anonymous (not verified)

Sadly, this seems true. I understand now why there won't be an FX Steamroller CPU; it's just nowhere near competitive to the Intel counterparts. As a longtime AMD enthusiast, I am saddened by this, but by the same token, if I were the CEO of AMD, it would be hard for me to make a business case to invest the engineering resources to catch up (strictly referring to integer performance). The future seems to be phablets, tablets, and convertibles.

January 14, 2014 | 10:38 AM - Posted by collie (not verified)

but that is kinda the point isnit? race to the bottom.
Most users but the cheapest option possible, that is why there are so many people with atom (pre silvermont) and low end celeron systems, constantly complaining how shity their laptop is.
A good enough cpu {and lets face it modern day low end cpu's are more than powerful enough for 90% of home users} with a good entry level gpu for around $600 will be the biggest sellers. It's just good business. AMD pushing the low end by making said low end systems good enough to play games at very decent quality will encourage the pc gaming ecosystem to once and for all dominate the console.

January 14, 2014 | 05:29 PM - Posted by Anonymous (not verified)

The money(Profits) have never been in High End gamimg, for Intel, at least, and have never been in high end gaming. Intel has always developed for the server, and mainstream market. Intel bases it chips for the enthusiast market arouund its server SKUs, with the server specific functionality removed, or fused off! Intel has always subsidized its gaming SKUs, with its profits from its server, and mainstream sales! AMD can not afford to do this subsidizing, and never really could, to the degree that Intel could! The whole profitable part of the market has shifted to the Moble Tablet/Phone, and low cost laptop/chromebook markets, that is where the money is, and AMD currently can only remain viable as a ongoing concern, by shifting its resources towards the GPU/APU market where it beats Intel, and competes with Nvidia! AMD does provide Intel with plenty of competition in the LOW cost, low to midrange(With Karvei) CPU/APU market! Intel is in deep trouble, in the low cost x86 market, and currently is not a factor in the Mobile CPU/APU market!

Loan AMD half a billion to restart its high end development, and you better have a few billion in reserve for a revolving line of funding, beacuse that is the level of subsidizing that gaming high end development costs!

Put your big money where your pouts are!

January 14, 2014 | 05:35 PM - Posted by Anonymous (not verified)

Edit: gaming high end development
TO: gaming high end CPU development

January 14, 2014 | 11:07 AM - Posted by mAxius

well this cements amd's mobile shift they probably have nothing to compete with intel's performence on the desktop/server side till excavator or after... I will give them credit though they were handed a bunch of lemons and made the best lemonade they could.

January 14, 2014 | 01:54 PM - Posted by Chipshot (not verified)

Congrats to AMD! A $120 Kaveri and siblings that beats higher priced Intel i3/i5 at PCMark8 and even the i7-4770k at games like Battlefield 4.

The last time AMD won in PCMark8 over equivalent Intel CPUs they took the majority of market share and with HSA acceleration, TrueAudio and Mantle, they are likely to do it again.

January 15, 2014 | 05:30 AM - Posted by SAnonymous (not verified)

Erm....which graphs are you looking at? Get off the weed

January 16, 2014 | 12:15 PM - Posted by StewartGraham (not verified)

Probably referring to the 7850k APU

January 14, 2014 | 02:03 PM - Posted by Dreadteir

I've always wondered with AMD how long it would be before they try and make a push to have a GDDR5 memory slot included on Fusion Motherboards. Presumably it would give the built in GCN cores quite a boost in performance and gaming.

January 14, 2014 | 02:47 PM - Posted by Anonymous (not verified)

Intel IPC has been at a virtual standstill since Sandy Bridge (2009) with most of the improvements that do exist coming from tangental features such as dynamic turbo/power modes.

AMD, what the hell are you doing?? Five years. Intel has gifted you five_goddamn_years of making virtually zero IPC progress, and you still can't catch them?

It's like a modern version of the goddamn tortoise and the hare with the hare deliberately doing everything it can to stall on purpose, and yet is still unable to lose the race.

January 15, 2014 | 12:48 AM - Posted by Nilbog

To be fair in the end, the tortoise won the race. Though your point still stands.

I also don't think Intel is stalling for them to catch up (though that would be nice). Intel just plain doesn't care, they consider ARM the threat now. They know AMD isn't going to be catching up for quite a while. Given the way things are going, they can just sit on new stuff until someone actually comes to compete.

January 15, 2014 | 12:53 PM - Posted by Anonymous (not verified)

Intel is not in the technology improving business, they are in the technology Milking business, Milking those customers for Profit business!!

January 16, 2014 | 12:17 PM - Posted by StewartGraham (not verified)

I'm sure AMD would be just fine if they had Intel's budget.

January 14, 2014 | 03:29 PM - Posted by Dude (not verified)

Everyone is focusing on the APU stuff.

I'm surprised that im about to update my 1st gen i7 940 to a haswell 4770k, and the actual performance gain is *only* 2x. For a 5-6 years update cycle, that is quite disappointing :/

quick question btw, is there a haswell cpu around that price range with no gpu but more power? i wish i could drop the GPU entirelly and spend the same or a tad more money on a faster cpu.

January 14, 2014 | 03:44 PM - Posted by Ryan Shrout

You can find some models that don't have the GPU portion but they aren't going to run faster than the models WITH processor graphics.  :/

January 14, 2014 | 03:51 PM - Posted by nashathedog (not verified)

Haswell-e is not due yet, Sandy-e or the newer Ivy-bridge-e are the only options. Because Ivy-e uses the same platform as Sandy-e I decided to go with a 4770k for now and I'm saving for when Haswell-e is released. From what I've read that will have a fairly decent performance improvement. Ivy-e is not much better than Sandy-e just like the Sandy/Ivy-Haswell improvements are minimal.

January 14, 2014 | 03:57 PM - Posted by Anonymous (not verified)

Please do not forget to define AMD's mobile tablet based APUs use of the Mobile/Full versions of openCL, openGL, etc, as Nivida's Tegra K1, now supports the desktop/descrete GPU, full versions of openCL, etc., on Nvidia's new mobile Tegra K1 based platforms! AMD needs to offer Full version support of OpenCL, etc. drivers on any SKUs that compete with the Nivida Tegra K1s! In the Future, with respect to any reviews of Mobile devices built around the AMD Kaveri mobile APUs in competition with the Nvidia Tegra K1 based mobile devices based "APU Type" CPU/GPU systems, please make sure to tell the reader if the mobile device will allow loading of a full Linux distro, and if that mobile divice's CPU/GPU APU, or "APU" type(Nvidia k1, etc) system supports the full openCL, etc. versions of the drivers! I am seriously looking for the K1 based tablet devices, and their K1 based ability to run full desktop style applications via full version openCL, OpenGL driver support, to allow me to run Blender 3d(Light Mesh Modeling) and Gimp for graphics, on a mobile tablet, that can run a full Linux Distro. Full openCL, openGL driver support on a Tablet/Mobile processor(K1, YES), (Kaveri, ??), is big news, and I look forward to your device reviews.

January 14, 2014 | 04:22 PM - Posted by Sean (not verified)

here's the problem, One chip, one price, just like how the Nvidia didn't get the consoles.. all three.. they will not be able to beat the price/performance point. I own two NVidia cards. from a business stand point, this spells bad news for Nvidia and anyone else in the smaller factor market. lots of power, all in one, less Watts. this is not high end. I hope they release high end chips but.. I'm beginning to think its not going to happen in the economy

January 14, 2014 | 06:18 PM - Posted by Anonymous (not verified)

What did the post, that you replied to, have to say, about what you are talking about? the Poster needs full Linux capability, and full OpenCL, OpenGL from a Mobile "APU"/APU type device(tablet) Nvidia's K1, can provide FULL openCL, openGL support, and the poster hopes AMD can provide an equivalent level of support, with its competiting SKUs!
The poster will buy any tablet, even it was made by marvin the martian, if it meets the posters needs, the poster wants a tablet that runs a full linux rooted distro, that can run Blender 3d, and gimp(both reguire Full OpenGL, and Maybe some Full OpenCL support, and run under windows[Hell no], or Linux)! the Poster would prefer a mobile x86 AMD platform(if it has full OpenGL, openCL, etc. support like The K1), but will use the K1 if there is A blender 3d, and Gimp, Arm based build available, to run on the linux distro based ARM platform! The K1 will compete very well in its intended form factor against the AMD kaveri tablet APUs! BUT no Blender 3d, no Gimp, and No full linux rooted distro, on the tablet, NO BUY!

January 16, 2014 | 12:24 PM - Posted by StewartGraham (not verified)

The Poster's statement was poorly written and incredibly verbose making it more difficult to distill relevant content.

January 14, 2014 | 07:15 PM - Posted by Anonymous (not verified)

Good upgrade when compared to the previous generation... it is matching and at times even beat the A10 5800K despite being a lower end part. Yes, it doesn't beat a core i3 in single threaded stuff but the multi-threaded performance is decent.

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