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
A Quick Refresher on the RV770
As Cypress is a direct evolution of the RV770 design, before we talk about what’s new with Cypress we are going to go over a quick rehash of RV770’s internal workings. As it’s necessary to understand how RV770 was built to understand what Cypress changes, if you’re completely unfamiliar with RV770, please take a look at our expanded discussion of RV770 from last year. For the rest of you, let’s get started.
At the center of the RV770 is the Stream Processing Unit (SPU), a single arithmetic logic unit. The RV770 has 800 of these, and they are packaged together in groups of 5 and are what we call a Streaming Processor (SP). A SP contains a register file, a branch predictor, and the aforementioned 5 SPUs, with the 5th SPU being a more complex unit capable of transcendental functions along with the base functions of an ALU. The SP is the smallest unit that can do individual work; every SPU in an SP must execute the same instruction.
For every 16 SPs, AMD groups them together with texture units, L1 cache, shared memory, and controlling logic. This combined block is what AMD calls a SIMD, and RV770 has 10 of them. These 10 SIMDs form the core computational power of the RV770, and in the chip work with various specialized units such as ROPs, rasterizers, L2 cache, and tesselators to form a complete chip.
To utilize the computational power of the hardware, instruction threads are issued to the SPs. These threads are grouped into wavefronts, where there are 64 threads per wavefront. To maximize the utilization of the GPU, threads need to be organized so that they can feed all 5 SPUs in a SP an instruction every clock cycle. Doing this requires extracting instruction level parallelism (ILP) out of programs being passed to the GPU, which is difficult task of AMD’s compiler.
If SPUs go unused, then the performance of the chip suffers due to underutilization. This design gives AMD a great deal of theoretical computational power, but it is always a challenge to fully exploit it.
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RubberJohnny - Thursday, September 24, 2009 - link
Well silicondoc you sure have some hatred for ATI/love for nvidia.It's almost as if you work for the green team...
You seem to have all this time on your hands to go around the net looking for links to spread FUD...sitting on new egg watching these cards come in and out of stock like you have a vested interest in seeing ATI fail...unlike any sane person it appears you want nvidia to have a monopoly on the industry?
Maybe you are privy to some inside info over at nvidia and know they have nothing to counter the 5870 with?
Maybe the cash they paid you to spin these BS comments would have been better spent on R&D?
SiliconDoc - Thursday, September 24, 2009 - link
That's a nice personal, grating, insulting ripppp, it's almost funny, too.---
The real problems remain.
I bring up this stuff because of course, no one else will, it is almost forbidden. Telling the truth shouldn't be that hard, and calling it fairly and honestly should not be such a burden.
I will gladly take correction when one of you noticing insulters has any to offer. Of course, that never comes.
Break some new ground, won't you ?
I don't think you will, nor do I think anyone else will - once again, that simply confirms my factual points.
I guess I'll give you a point for complaining about delivery, if that's what you were doing, but frankly, there are a lot of complainers here no different - let's take for instance the ATI Radeon HD 4890 vs. NVIDIA GeForce GTX 275 article here.
http://www.anandtech.com/video/showdoc.aspx?i=3539">http://www.anandtech.com/video/showdoc.aspx?i=3539
Boy, the red fans went into rip mode, and Anand came in and changed the articles (Derek's) words and hence "result", from GTX275 wins to ATI4890 wins.
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No, it's not just me, it's just the bias here consistently leans to ati, and wether it's rooting for the underdog that causes it, or the brooding undercurrent hatred that surfaces for "the bigshot" "greedy" "ripoff artist" "nvidia overchargers" "industry controlling and bribing" "profit demon" Nvidia, who knows...
I'm just not afraid to point it out, since it's so sickening, yes, probably just to me, "I'm sure".
How about this glaring one I have never pointed out even to this day, but will now:
ATI is ALWAYS listed first, or "on top" - and of course, NVIDIA, second, and it is no doubt, in the "reviewer's minds" because of "the alphabet", and "here we go in alphabetical order".
A very, very convenient excuse, that quite easily causes a perception bias, that is quite marked for the readers.
But, that's ok.
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So, you want to tell me why I shouldn't laugh out loud when ATI uses NVIDIA cards to develope their "PhysX" competition Bullet ?
ROFLMAO
I have heard 100 times here (from guess whom) that the ati has the wanted "new technology", so will that same refrain come when NVIDIA introduces their never before done MIMD capable cores in a few months ? LOL
I can hardly wait to see the "new technology" wannabes proclaiming their switched fealty.
Gee sorry for noticing such things, I guess I should be a mind numbed zombie babbling along with the PC required fanning for ati ?
silverblue - Thursday, September 24, 2009 - link
No; if he did work for nVidia, he'd be far better informed and far less prone to using the phrase "red rooster" every five seconds.crackshot91 - Wednesday, September 23, 2009 - link
Any possibility of benchmarks with a core 2 duo?I wanna know if it will be necessary to upgrade to an i5 or i7 (All new mobo) to see big performance gains over my 8800GT. Will a C2D E6750 @ 3.2GHz bottleneck it?
Ryan Smith - Wednesday, September 23, 2009 - link
Our recent Core i7 860 article should do an adequate job of answering that question. Several of the benchmarks were taken right out of this article.therealnickdanger - Wednesday, September 23, 2009 - link
You dedicated a full page to the flawless performance of its A/V output, but didn't mention it in the "features" part of the conclusion. It's a very powerful feature, IMO. Granted, this card may be a tad too hot and loud to find a home in a lot of HTPCs, but it's still an awesome feature and you should probably append your conclusion... just a suggestion though.Ultimately, I have to admit to being a little disappointed by the performance of this card. All the Eyefinity hype and playable framerates at massive 7000x3000 resolutions led me to believe that this single card would scale down and simply dominate everything at the 30" level and below. It just seems logical, so I was taken aback when it was beat by, well, anything else. I expected the 5870 and 5870CF to be at the top of every chart. Oh well.
Awesome article though! I'm sure there's a 5850 in my future!
MrMom - Wednesday, September 23, 2009 - link
Does anyone have a good explanation why the massive HD5870 is still slower/@par with the GTX295?Thanks
SiliconDoc - Thursday, September 24, 2009 - link
Yes, because the ati core "really sucks". It needs DDR5, and much higher MHZ to compete with Nvidia, and their what, over 1 year old core. LOL Even their own 4870x2.Or the 3 year old G92 vs the ddr3 "4850" the "topcore" before yesterday. (the ati topcore minus the well done 3m mhz+ REBRAND ring around the 4890)
That's the sad, actual truth. That's the truth many cannot bear to bring themselves to realize, and it's going to get WORSE for them very soon, with nvidia's next release, with ddr5, a 512 bit bus, and the NEW TECHNOLOGY BY NVIDIA THAT ATI DOES NOT HAVE MIMD capable cores.
Oh, I can hardly wait, but you bet I'm going to wait, you can count on that 100%.
Spoelie - Thursday, September 24, 2009 - link
because those are 2 480mm² dies, while this is only 1 360mm² die?Griswold - Wednesday, September 23, 2009 - link
Its one GPU instead of two, maybe?