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
Conclusion
The easiest kind of product for us to write about is the kind that’s clearly superior to its competition. The hardest kind to write about is the kind that’s stuck in the middle. For the 5870, we have the latter case.
Let’s be clear here: the 5870 is the single fastest single-GPU card we have tested, by a wide margin. Looking at its performance in today’s games, as a $379 card it makes the GTX 285 at its current prices ($300+) completely irrelevant. The price difference isn’t enough to make up for the performance difference, and NVIDIA also has to contend with the 5850, which should perform near the GTX 285 but at a price of $259. As is often the case with a new generation of cards, we’re going to see a shakeup here in the market as NVIDIA in particular needs to adjust to these new cards.
The catch however is that what we don’t have is a level of clear domination when it comes to single-card solutions. AMD was shooting to beat the GTX 295 with the 5870, but in our benchmarks that’s not happening. The 295 and the 5870 are close, perhaps close enough that NVIDIA will need to reconsider their position, but it’s not enough to outright dethrone the GTX 295. NVIDIA still has the faster single-card solution, although the $100 price premium is well in excess of the <10% performance premium.
Meanwhile AMD is retiring the 4870X2, which ended up beating the 5870 enough that we would consider it a competitor to the 5870. However, you can’t consider it if you can’t buy it.
Then we have the multi-GPU space, where things are rather clear. Having the fastest single-GPU card makes the 5870 in Crossfire the fastest dual-GPU solution by far. Unfortunately we didn’t have a chance to benchmark a GTX 295 Quad SLI setup, but given the notoriously finicky nature of Quad SLI and Quad Crossfire, we’re comfortable calling the 5870 CF the better multi-GPU solution.
And that brings us to our next conundrum: if dual-GPU setups can overshoot the 5870, does that make them better? At equal performance levels, we would take a single-GPU setup any day of the week; there are no profiles to deal with or the sometimes inconsistent scaling in performance (see: Dawn of War II). Even with a slight lead in performance, we would pick the 5870 over the 4870X2 or GTX 295 so long as the latter were not significantly cheaper. As it stands the 5870 is the greater value, even if it's not the fastest card.
Moving away from performance, we have feature differentiation. AMD has a clear advantage here with DirectX11, as the 5870 is going to be a very future-proof card. The 8800GTX is a good parallel here – it took 3 years for it to really be outclassed in terms of features, and the performance is still respectable today. DX11 is going to give the 5870 the same level of longevity when it comes to being up-to-date on features, although we’ll see if its performance lasts for quite as long. When games using DX11 arrive, it’s going to bring about a nice change in quality (particularly with tessellation). However it’s going to be a bit of a wait to get there.
On that tangent, we have Eyefinity. Unlike DX11 Eyefinity is something we can take advantage of today, but also unlike DX11 it’s not necessarily an improvement. As Anand discussed when attempting to use it, when it works it’s absolutely great, but at the moment it has some real teething issues. And it’s expensive – even 3 cheap TV-quality monitors is an investment for most people of hundreds of dollars on top of everything else. It’s very much like a certain NVIDIA feature in terms of cost, goals, and its hit-or-miss nature. Eyefinity is something we’re going to want to keep an eye on to see what AMD does with it in the future, because they’re on the right track. It’s just not something that’s going to tickle the fancy of very many people today.
Wrapping things up, for those of you who were expecting the 5870 to shake things up, the 5870 is certainly going to do that. For those of you looking for the above and a repeat of the RV770/GT200 launch where prices will go into a free fall, you’re going to come away disappointed. That task will fall upon the 5850, and we’re looking forward to reviewing it as soon as we can.
At the end of the day, with its impressive performance and next-generation feature set, the Radeon HD 5870 kicks off the DirectX 11 generation with a bang and manages to take home the single-GPU performance crown in the process. It’s without a doubt the high-end card to get.
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Zool - Sunday, September 27, 2009 - link
The speed of the on chip cache just shows that the external memory bandwith in curent gpus is only to get the data to gpu or recieve the final data from gpu. The raw processing hapenns on chip with those 10 times faster sram cache or else the raw teraflops would vanish.JarredWalton - Sunday, September 27, 2009 - link
If SD had any reading comprehension or understanding of tech, he would realize that what I am saying is:1) Memory bandwidth didn't double - it went up by just 23%
2) Look at the results and performance increased by far more than 23%
3) Ergo, the 4890 is not bandwidth limited in most cases, and there was no need to double the bandwidth.
Would more bandwidth help performance? Almost certainly, as the 5870 is such a high performance part that unlike the 4890 it could use more. Similarly, the 4870X2 has 50% more bandwidth than the 5870, but it's never 50% faster in our tests, so again it's obviously not bandwidth limited.
Was it that hard to understand? Nope, unless you are trying to pretend I put an ATI bias on everything I say. You're trying to start arguments again where there was none.
SiliconDoc - Sunday, September 27, 2009 - link
The 4800 data rate ram is faster vs former 3600 - hence bus width is running FASTER - so your simple conclusions are wrong.When we overlcock the 5870's ram, we get framerate increase - it increases the bandwidth, and up go the numbers.
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Not like there isn't an argument, because you don't understand tech.
JarredWalton - Sunday, September 27, 2009 - link
The bus is indeed faster -- 4800 effective vs. 3900 on the 4890 or 3600 on the 4870. What's "wrong about my simple conclusions"? You're not wrong, but you're not 100% right if you suggest bandwidth is the only bottleneck.Naturally, as most games are at least partially bandwidth limited, if you overclock 10% you increase performance. The question is, does it increase linearly by 10%? Rarely, just as if you overclock the core 10% you usually don't get 10% boost. If you do get a 1-for-1 increase with overclocking, it indicates you are solely bottlenecked by that aspect of performance.
So my conclusions still stand: the 5870 is more bandwidth limited than 4890, but it is not completely bandwidth limited. Improving the caches will also help the GPU deal with less bandwidth, just as it does on CPUs. As fast as Bloomfield may be with triple-channel DDR3-1066 (25.6GB/s), the CPU can process far more data than RAM could hope to provide. Would a wider/faster bus help the 5870? Yup. Would it be a win-win scenario in terms of cost vs. performance? Apparently ATI didn't think so, and given how quickly sales numbers taper off above $300 for GPUs, I'm inclined to agree.
I'd also wager we're a lot more CPU limited on 5870 than many other GPUs, particularly with CrossFire setups. I wouldn't even look at 5870 CrossFire unless you're running a high-end/overclocked Core i7 or Phenom II (i.e. over ~3.4GHz).
And FWIW: Does any of this mean NVIDIA can't go a different route? Nope. GT300 can use 512-bit interfaces with GDDR5, and they can be faster than 5870. They'll probably cost more if that's the case, but then it's still up to the consumers to decide how much they're willing to spend.
silverblue - Saturday, September 26, 2009 - link
I suppose if we end up seeing a 512-bit card then it'll make for a very interesting comparison with the 5870. With equal clocks during testing, we'd have a far better idea, though I'd expect to see far more RAM on a 512-bit card which may serve to skew the figures and muddy the waters, so to speak.Voo - Friday, September 25, 2009 - link
Hey Jarred I know that's neither the right place nor the right person to ask, but do we get some kind of "Ignore this person" button with the site revamp Anand talked about some months ago?I think I'd prefer this feature about almost everything - even an edit button ;)
JarredWalton - Friday, September 25, 2009 - link
I'll ask and find out. I know that the comments are supposed to receive a nice overhaul, but more than that...? Of course, if you ignore his posts on this (and the responses), you'd only have about five comments! ;-)Voo - Saturday, September 26, 2009 - link
Great!Yep it'd be rather short, but I'd rather have 10 interesting comments than 1000 COMMENTS WRITTEN IN CAPS!!11 with dubious content ;)
SiliconDoc - Wednesday, September 30, 2009 - link
I put it in caps so you could easily avoid them, I was thinking of you and your "problems".I guess since you "knew this wasn't the right time or place" but went ahead anyway, you've got "lot's of problems".
Let me know when you have posted an "interesting comment" with no "dubios nature" to it.
I suspect I'll be waiting years.
MODEL3 - Friday, September 25, 2009 - link
Hi Ryan,Nice new info in your review.
The day you posted your review, i wrote in the forums that according to my perception there are other reasons except bandwidth limitations and driver maturity, that the 850MHz 5870 hasn't doubled its performance in relation with a 850MHz 4890.
Usually when a GPU has 2X the specs of another GPU the performance gain is 2X (of cource i am not talking about games with engines that are CPU limited or engines that seems to scale badly or are poor coded for example)
There are many examples in the past that we had 2X performance gain with 2X the specs. (not in all the games, but in many games)
From the tests that i saw in your review and from my understanding of the AMD slides, i think there are 2 more reasons that 5870 performs like that.
The day of your review i wrote to the forums the additional reasons that i think the 5870 performs like that, but nobody replied me.
I wrote that probably 5870 has:
1.Geometry/vertex performance issues (in the sense that it cannot generate 2X geometry in relation with 4890) (my main assumption)
or/and
2.Geometry/vertex shading performance issues (in the sense that the geometry shader [GS] cannot shade vertex with 2X speed in relation with 4890)(another possible assumption)
I guess there are synthetic benchmarks that have tests like that (pure geometry speed, and pure geometry/vertex shader speed, in addition with the classic pixel shader speed tests) so someone can see if my assumption is true.
If you have the time and you think that this is possible and you feel like it is worth your time, can you check my hypothesis please?
Thanks very much,
MODel3