AMD's Radeon HD 5870: Bringing About the Next Generation Of GPUs
by Ryan Smith on September 23, 2009 9:00 AM EST- Posted in
- GPUs
DirectCompute, OpenCL, and the Future of CAL
As a journalist, GPGPU stuff is one of the more frustrating things to cover. The concept is great, but the execution makes it difficult to accurately cover, exacerbated by the fact that until now AMD and NVIDIA each had separate APIs. OpenCL and DirectCompute will unify things, but software will be slow to arrive.
As it stands, neither AMD nor NVIDIA have a complete OpenCL implementation that's shipping to end-users for Windows or Linux. NVIDIA has OpenCL working on the 8-series and later on Mac OS X Snow Leopard, and AMD has it working under the same OS for the 4800 series, but for obvious reasons we can’t test a 5870 in a Mac. As such it won’t be until later this year that we see either side get OpenCL up and running under Windows. Both NVIDIA and AMD have development versions that they're letting developers play with, and both have submitted implementations to Khronos, so hopefully we’ll have something soon.
It’s also worth noting that OpenCL is based around DirectX 10 hardware, so even after someone finally ships an implementation we’re likely to see a new version in short order. AMD is already talking about OpenCL 1.1, which would add support for the hardware features that they have from DirectX 11, such as append/consume buffers and atomic operations.
DirectCompute is in comparatively better shape. NVIDIA already supports it on their DX10 hardware, and the beta drivers we’re using for the 5870 support it on the 5000 series. The missing link at this point is AMD’s DX10 hardware; even the beta drivers we’re using don’t support it on the 2000, 3000, or 4000 series. From what we hear the final Catalyst 9.10 drivers will deliver this feature.
Going forward, one specific issue for DirectCompute development will be that there are three levels of DirectCompute, derived from DX10 (4.0), DX10.1 (4.1), and DX11 (5.0) hardware. The higher the version the more advanced the features, with DirectCompute 5.0 in particular being a big jump as it’s the first hardware generation designed with DirectCompute in mind. Among other notable differences, it’s the first version to offer double precision floating point support and atomic operations.
AMD is convinced that developers should and will target DirectCompute 5.0 due to its feature set, but we’re not sold on the idea. To say that there’s a “lot” of DX10 hardware out there is a gross understatement, and all of that hardware is capable of supporting at a minimum DirectCompute 4.0. Certainly DirectCompute 5.0 is the better API to use, but the first developers testing the waters may end up starting with DirectCompute 4.0. Releasing something written in DirectCompute 5.0 right now won’t do developers much good at the moment due to the low quantity of hardware out there that can support it.
With that in mind, there’s not much of a software situation to speak about when it comes to DirectCompute right now. Cyberlink demoed a version of PowerDirector using DirectCompute for rendering effects, but it’s the same story as most DX11 games: later this year. For AMD there isn’t as much of an incentive to push non-game software as fast or as hard as DX11 games, so we’re expecting any non-game software utilizing DirectCompute to be slow to materialize.
Given that DirectCompute is the only common GPGPU API that is currently working on both vendors’ cards, we wanted to try to use it as the basis of a proper GPGPU comparison. We did get something that would accomplish the task, unfortunately it was an NVIDIA tech demo. We have decided to run it anyhow as it’s quite literally the only thing we have right now that uses DirectCompute, but please take an appropriately sized quantity of salt – it’s not really a fair test.
NVIDIA’s ocean demo is a fairly simple proof of concept program that uses DirectCompute to run Fast Fourier transforms directly on the GPU for better performance. The FFTs in turn are used to generate the wave data, forming the wave action seen on screen as part of the ocean. This is a DirectCompute 4.0 program, as it’s intended to run on NVIDIA’s DX10 hardware.
The 5870 has no problem running the program, and in spite of whatever home field advantage that may exist for NVIDIA it easily outperforms the GTX 285. Things get a little more crazy once we start using SLI/Crossfire; the 5870 picks up speed, but the GTX 295 ends up being slower than the GTX 285. As it’s only a tech demo this shouldn’t be dwelt on too much beyond the fact that it’s proof that DirectCompute is indeed working on the 5800 series.
Wrapping things up, one of the last GPGPU projects AMD presented at their press event was a GPU implementation of Bullet Physics, an open source physics simulation library. Although they’ll never admit it, AMD is probably getting tired of being beaten over the head by NVIDIA and PhysX; Bullet Physics is AMD’s proof that they can do physics too. However we don’t expect it to go anywhere given its very low penetration in existing games and the amount of trouble NVIDIA has had in getting developers to use anything besides Havok. Our expectations for GPGPU physics remains the same: the unification will come from a middleware vendor selling a commercial physics package. If it’s not Havok, then it will be someone else.
Finally, while AMD is hitting the ground running for OpenCL and DirectCompute, their older APIs are being left behind as AMD has chosen to focus all future efforts on OpenCL and DirectCompute. Brook+, AMD’s high level language, has been put out to pasture as a Sourceforge project. Compute Abstract Layer (CAL) lives on since it’s what AMD’s OpenCL support is built upon, however it’s not going to see any further public development with the interface frozen at the current 1.4 standard. AMD is discouraging any CAL development in favor of OpenCL, although it’s likely the High Performance Computing (HPC) crowd will continue to use it in conjunction with AMD’s FireStream cards to squeeze every bit of performance out of AMD’s hardware.
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avaughan - Wednesday, September 23, 2009 - link
Ryan,When you review the 5850 can you please specify memory size for all the comparison cards. At a guess the GTS 250 had 1GB and the 9800GT had 512 ?
Thanks
ThePooBurner - Wednesday, September 23, 2009 - link
With a full double the power and transistors and everything else including optimizations that should get more band for buck out of each one of those, why are we not seeing a full double the performance in games compared to the previous generation of cards?SiliconDoc - Wednesday, September 23, 2009 - link
Umm, because if you actually look at the charts, it's not "double everything".In fact, it's not double THE MOST IMPORTANT THING, bandwidth.
For pete sakes an OC'ed GTX260 core 192 get's to 154+ bandwidth rather easily, surpassing the 153.6 of ati's latest and greatest.
So, you have barely increased ram speed, same bus width... and the transistors on die are used up in "SHADERS" and ROPS....etc.
Where is all that extra shader processing going to go ?
Well, it goes to SSAA useage for instance, which provides ZERO visual quality improvement.
So, it goes to "cranking up the eye candy settings" at "not a very big framerate improvement".
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So they just have to have a 384 or a 512 bus they are holding back. I dearly hope so.
They've already been losing a BILLION a year for 3+ years in a row, so the cost excuse is VERY VERY LAME.
I mean go check out the nvidia leaked stats, they've been all over for months - DDR5 and a 512 bit, with Multiple IMD, instead of the 5870 Single IMD.
If you want DOUBLE the performance wait for Nvidia. From DDR3 to DDR5, like going from 4850 to 4890, AND they (NVIDIA) have a whole new multiple instruction super whomp coming down the pike that is never done before, on their hated "gigantic brute force cores" (even bigger in the 40nm shrink -lol) that generally run 24C to 15C cooler than ati's electromigration heat generators.
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So I mean add it up. Moving to DDR5, moving to multiple data, moving to 40nm, moving with 512 bit bus and AWESOME bandwidth, and the core is even bigger than the hated monster GT200. LOL
We're talking EPIC palmface.
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In closing, buh bye ati !
silverblue - Thursday, September 24, 2009 - link
Let's wait for GT300 before we make any sweeping generalisations. The proof is in the pudding and it won't be long before we see it.And don't let the door hit you on the way out.
SiliconDoc - Thursday, September 24, 2009 - link
Oh mister, if we're waiting, that means NO BUYING the 5870, WAIT instead.Oh, yeah, no worries, it's not available.
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Now, when my statements prove to be true, and your little crybaby snark with NO FACTS used for rebuttal are proven to be wasted stupidity, WILL YOU LEAVE AS YOU STATED YOU WANT ME TO ?
That's what I want to know. I want to know if your little wish applies to YOU.
Come on, I'll even accept a challenge on it. If I turn out to be wrong, I leave, if not you're gone.
If I'm correct, anyone waiting because of what I've pointed out, has been given an immense helping hand.
Which BY THE WAY, the entire article FAILED TO POINT OUT, because the red love goes so deep here.
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But, you, the little red rooster ati fanner, wants me out.
ROFL - you people are JUST INCREDIBLE, it is absolutely incredible the crap you pull.
NOW, LET US KNOW WHAT LEAKED NVIDIA STATS I GOT INCORRECT WON'T YOU!?
No of course you won't !
silverblue - Friday, September 25, 2009 - link
Another problem I have with people like you is the unerring desire to rant and rave without reading things through. I said wait for GT300 before doing a proper comparison. Have you already forgotten the mess that was NV30? Paper specs do not necessarily equal reality. When the GT300 is properly previewed, even with an NDA in place, we can all judge for ourselves. People have a choice to buy what they like regardless of what you or I say.I'm not an ATI fanboy. I expended plenty of thought on what parts to get when I upgraded a few months back and that didn't just include CPU but motherboard and graphics. I was very close to getting a higher end Core2 Duo along with an nVidia graphics card; at the very least I considered an nVidia graphics card even when I decided on an AMD CPU and motherboard. In the end I felt I was getting better value by choosing an ATI solution. Doesn't make me a fanboy just because my money didn't end up on the nVidia balance sheet.
I'll take back the little comment about letting the door hit you on the way out. It wasn't designed to tell you to go away and not come back again, so my bad. I was annoyed at your ability to just attack a specific brand without any apparent form of objectivity. If you hate ATI, then you hate ATI, but do we really need to hear it all the time?
If the information you've posted about the GT300 is indeed accurate and comparable to what we've been told about the 58x0 series, then that's great, but you're going to need to lay it out in a more structured format so people can digest it more readily, as well as lay off the constant anti-ATI stance because appearing biased is not going to make people more receptive to your viewpoint. I remain sceptical that your leaked specs will end up being correct but in the end, GT300 is on its way and it'll be a monster regardless of whatever information you've posted here. I'm not going to pretend I know anything technical about GT300, but you must realise that what you've essentially done in this article is slate a working, existing product line that is being distributed to vendors as we speak in a manner that's much slower than ATI had intended yet you're attacking people for being interested in it over the GT300 which hasn't been reviewed yet, partly because you think the product is vapourware (which isn't really the case as people are getting hold of the 5870 but at a lower rate than ATI would like). Some people will choose to wait, some people will jump on the 58x0 bandwagon right now, but it's not for you to decide for them what they should buy.
Now relax, you're going to have a heart attack.
SiliconDoc - Wednesday, September 30, 2009 - link
What a LOAD OF CRAP.I don't have to outline anything, remember, ALL YOU PEOPLE cARE ABOUT IS GAMING FRAMERATE.
And that at "your price point" that doesn't include "the NVIDIA BALANCE SHEET". - which io of course, the STRANGEST WAY for a reddie to put it.
YOU JUST WANT ME TO SHUT UP. YOU DON'T WANT IT SAID. WE'LL I'M SAYING IT AGAIN, AND YOU FAILED TO ACCEPT MY CHALLENGE BECAUSE YOU'RE A CHICKEN, AND CENSOR !
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Oh, do we have to hear it... blah blah blah blah...
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YES SINCE THIS VERY ARTICEL WAS ABSOLUTELY IRRESPONSIBLE IN NOT PROPERLY ASSESSING THE COMPETITION.
CarrellK - Wednesday, September 23, 2009 - link
If a game ran almost entirely on the GPU, the scaling would be more of what you expect. You can put in a new GPU, but the CPU is no faster, main memory is no faster of bigger, the hard disk is no faster, PCIE is no faster, etc.The game code itself also limits scaling. For example the texture size can exceed the card's memory footprint, which results in performance sapping texture swaps. Each game introduces different bottlenecks (we can't solve them all).
We do our best to get linear scaling, but the fact is that we address less than a third of the game ecosystem. That we do better than 33% out of a possible 100% improvement is I think a testimony to our engineers.
BlackbirdCaD - Wednesday, September 23, 2009 - link
Why no load temp of 5870 in Crossfire??Load temp is much more important than idle temp.
There is lots of uninteresting stuff like soundlevel at idle with 5870 in crossfire, but the MOST IMPORTANT is missing: load temp with 5870 in crossfire.
SiliconDoc - Wednesday, September 23, 2009 - link
I just pulled up the chart on the 4870 CF, and although the 4870x2 was low 400's on load system power useage, the 4870 CF was 722 watts !So, I think your question may have some validity. I do believe the cards get a bit hotter in CF, and then you have the extra items on the PCB, the second slot used, the extra ram via the full amount on each card - all that adds up to more power useage, more heat in the case, and higher temps communicating with eachother. (resends for data on bus puases waitings, etc. ).
So there is something to your question.
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Other than all that the basic answer is "red fan review site".
The ATI cards are HOTTER than the nvidia under load as a very, very wide general statement, that covers almost every card they both make, with FEW exceptions.