The Radeon HD 4850 & 4870: AMD Wins at $199 and $299
by Anand Lal Shimpi & Derek Wilson on June 25, 2008 12:00 AM EST- Posted in
- GPUs
AMD's RV770 vs. NVIDIA's GT200: Which one is More Efficient?
It is one thing to be able to sustain high levels of performance and altogether another to do it efficiently. AMD's architecture is clearly the more area efficient compared to NVIDIA.
Alright now, don't start yelling that RV770 is manufactured at 55nm while GT200 is a 65nm part: we're taking that into account. The die size of GT200 is 576mm^2, but if we look at scaling the core down to 55nm, we would end up with a 412mm^2 part with perfect scaling. This is being incredibly generous though, as we understand that TSMC's 55nm half-node process scales down die size much less efficiently one would expect. But lets go with this and give NVIDIA the benefit of the doubt.
First we'll look at area efficiency in terms of peak theoretical performance using GFLOPS/mm^2 (performance per area). Remember, these are just ratios of design and performance aspects; please don't ask me what an (operation / (s * mm * mm)) really is :)
| Normalized Die Size | GFLOPS | GFLOPS/mm^2 | |
| AMD RV770 | 260 mm^2 | 1200 | 4.62 |
| NVIDIA GT200 | 412 mm^2 | 933 | 2.26 |
This shows us that NVIDIA's architecture requires more than 2x the die area of AMD's in order to achieve the same level of peak theoretical performance. Of course theoretical performance doesn't mean everything, especially in light of our previous discussion on extracting parallelism. So let's take a look at real performance per area and see what we get in terms of some of our benchmarks, specifically Bioshock, Crysis, and Oblivion. We chose these titles because relative performance of RV770 is best compared to GT200 in Bioshock and worst in Oblivion (RV770 actually leads the GT200 in bioshock performance while the GT200 crushes RV770 in Oblivion). We included Crysis because it's engine is quite a popular and stressful benchmark that falls somewhere near the middle of the range in performance difference between RV770 and GT200 in the tests we looked at.
These numbers look at performance per cm^2 (because the numbers look prettier when multiplied by 100). Again, this doesn't really show something that is a thing -- it's just a ratio we can use to compare the architectures.
| Performance per Die Area | Normalized Die Size in cm^2 | Bioshock | Crysis | Oblivion |
| AMD RV770 | 2.6 | 27 fps/cm^2 | 11.42 fps/cm^2 | 10.23 fps/cm^2 |
| NVIDIA GT200 | 4.12 | 15.51 fps/cm^2 | 8.33 fps/cm^2 | 8.93 fps/cm^2 |
While it doesn't tell the whole story, it's clear that AMD does have higher area efficiency relative to the performance they are able attain. Please note that comparing these numbers directly doesn't yield anything that can be easily explained (the percent difference in frames per second per millimeter per millimeter doesn't really make much sense as a concept), which is part of why these numbers aren't in a graph but are in a table. So while higher numbers show that AMD is more area efficient, this data really doesn't show how much of an advantage AMD really has. Especially since we are normalizing sizes and looking at game performance rather than microbenches.
Some of this efficiency may come from architectural design, while some may stem from time spent optimizing the layout. AMD said that some time was spent doing area optimization on their hardware, and that this is part of the reason they could get more than double the SPs in there without more than doubling the transistor count or building a ridiculously huge die. We could try to look at transistor density, but transistor counts from AMD and NVIDIA are both just estimates that are likely done very differently and it might not reflect anything useful.
We can talk about another kind of efficiency though. Power efficiency. This is becoming more important as power costs rise, as computers become more power hungry, and as there is a global push towards conservation. The proper way to look at power efficiency is to look at the amount of energy it takes to render a frame. This is a particularly easy concept to grasp unlike the previous monstrosities. It turns out that this isn't a tough thing to calculate.
To get this data we recorded both frame rate and watts for a benchmark run. Then we look at average frame rate (frames per second) and average watts (joules per second). We can then divide average watts by average frame rate and we end up with: average joules / frames. This is exactly what we need to see energy per frame for a given benchmark. And here's a look at Bioshock, Crysis and Oblivion.
| Average energy per frame | Bioshock | Crysis | Oblivion |
| AMD RV770 | 4.45 J/frame | 10.33 J/frame | 11.07 J/frame |
| NVIDIA GT200 | 5.37 J/frame | 9.99 J/frame | 9.57 J/frame |
This is where things get interesting. AMD and NVIDIA trade off on power efficiency when it comes to the tests we showed here. Under Bioshock RV770 requires less energy to render a frame on average in our benchmark. The opposite is true for Oblivion, and NVIDIA does lead in terms of power efficiency under Crysis. Yes, RV770 uses less power to achieve it's lower performance in Crysis and Oblivion, but for the power you use NVIDIA gives you more. But RV770 leads GT200 in performance under Bioshock while drawing less power, which is quite telling about the potential of RV770.
The fact that this small subset of tests shows the potential of both architectures to have a performance per watt advantage under different circumstances means that as time goes on and games come out, optimizing for both architectures will be very important. Bioshock shows that we can achieve great performance per watt (and performance for that matter) on both platforms. The fact that Crysis is both forward looking in terms of graphics features and shows power efficiency less divergent than Bioshock and Oblivion is a good sign for (but not a guarantee of) consistent performance and power efficiency.
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paydirt - Wednesday, June 25, 2008 - link
This is a review site. This isn't a site to market/promote products.formulav8 - Thursday, June 26, 2008 - link
They do recommend hardware for different price points and such. So they do market in a way. Have you seen anands picks links? That is promoting products and does it through his referral links as well to get paid to do so. :)Anyways, mentioning something as a better buy up to a certain price point would be helpful to someone who is not really in the know.
Jason
shadowteam - Wednesday, June 25, 2008 - link
You've got excellent written skills buddy, and I can't help thinking you're actually better at reviews than your m8 (no offence Anand), but what I truly meant from my post above is what you summed up rather well in your conclusive lines, quote: "You can either look at it as AMD giving you a bargain or NVIDIA charging too much, either way it's healthy competition in the graphics industry once again (after far too long of a hiatus)"Either way? Why should anyone look the other way? NV is clearly shitting all over the place, and you can tell that from the email they send you (or Anand) a couple days back. So they ripped us off for 6 months, and now suddenly decide the 9800GTX is worth $200?
Healthy competition? Could you please elaborate on this further?
$199 4850 vs $399 GTX260.... yup! that's healthy
GTX+ vs 4850?
Does that mean the GTX260 is now completely irrelevant? In fact, the 2xx series is utterly pointless no matter how you look at it.
To bash on AMD, the 4870 is obviously priced high. For $100 extra, all you get is an OC'ed 4850 w/ DDR5 support. I don't think anyone here cares about DDR5, all that matters is performance, and the extra bucks plainly not worth it. From a consumers' perspective, the 4850 is the best buy, the 4870 isn't.
mlambert890 - Sunday, July 13, 2008 - link
"200 series is utterly pointless"Yep... pointless unless you want the fastest card (280), then it has a point.
Pointless to YOU possibly because you're focusing on perf per dollar. Good for you. Nice of you to presume to force that view on the world.
Absolute performance? GTX 280 seems near the top of every benchmark there bud. Both in single card and in SLI where, last I checked, it gives up maybe TWO instances to the 4870CF - Bioshock and CoD and in both cases framerates are north of 100 at 2560. The 4870, on the other hand, falls WELL short of playable at that res in CF in most other benches.
High res + high perf = 200 series. Sorry if thats offensive to the egos of those who cant afford the cards.
Theres a lot in life we can and cant afford. Should have ZERO impact on ABSOLUTE PERFORMANCE discussions.
FITCamaro - Wednesday, June 25, 2008 - link
AMD/ATI has to make some money somewhere. And regardless, at $300, the 4870 is a hell of a deal compared to the competition. Yes the 4850 is probably the best value. But the 4870 is still right behind it if you want a decent amount of extra performance at a great price.Nvidia may have the fastest thing out there. But only the richest, most brain dead idiots who have not a care in the world about how they spend their (or their parents) money will buy it with cards like the 4850 and 4870 available.
And its pretty sad when your new $650 high end card is routinely beat by two of your last generation cards (8800GT) that you can get for $150 each or less. It wouldn't be as big a deal if the new card was $300-350 but at $650, it should be stomping on it.
I think Nvidia is in for a reality check for what people want. If their new chips are only going to cater to the top 1% of the market, they're going to find themselves quickly in trouble. Especially with the all the issues their chipsets have for 6 months after release. And their shoddy drivers. I mean this past Friday I decided to try and set up some profiles so that when I started up Age of Conan, it would apply an overclock to my GPU and unapply it after I exited, it ended up locking up my PC continuously. I had to restore my OS from a backup disc because not even completely uninstalling and reinstalling my nvidia chipset and video drivers fixed it. And in my anger, I didn't back up my "My Documents" folder so I lost 5 years worth of stuff, largely pictures.
mlambert890 - Sunday, July 13, 2008 - link
"Nvidia may have the fastest thing out there. But only the richest, most brain dead idiots who have not a care in the world about how they spend their (or their parents) money will buy it with cards like the 4850 and 4870 available."You just summed it up in that first sentence there bud. NVidia has the fastest thing out there. The rest is just opinion, bitterness and noise.
I notice that the tone of the "enthusiast" community seems to be laser focused on cost now. This is like car discussions. People want to pretend to be "Xtreme" but what they really want to see is validation of whatever it is THEY can afford.
Have fun with the 4870 by all means, its a great card. But the GTX280 IS faster. Did NVidia price it too high? Dont know and dont care.
These are PERFORMANCE forums to all of the people that dont get that. Maybe even the editors need to be reminded.
If I want to see an obsession with "bang for the buck" Ill go to Consumer Reports.
I mean seriously. How much of a loser are you when you're taking a shot like "your PARENTS money"? LOL...
Personally, I treat the PC hobby as an expensive distraction. Ive been a technology pro for 15 years now and this is my vice. As an adult earning my own money, I can decide how I spend it and the difference between $500 and a grand isnt a big deal.
The rehtoric on forums is really funny. People throw the "kid/parents" insult around alot, but I think its more likely that the people who take prices beyond what they can afford as some kind of personal insult are more likely the kids here.
formulav8 - Thursday, June 26, 2008 - link
"Nvidia may have the fastest thing out there. But only the richest, most brain dead idiots who have not a care in the world about how they spend their (or their parents) money will buy it with cards like the 4850 and 4870 available."Yuk Yuk Yuk :)
Jason
drpepper128 - Wednesday, June 25, 2008 - link
To be honest, while I was reading the article I felt as if the article seemed a little ATI biased, but I guess that goes to show you that two different people can get drastically different opinions from the same article.The real reason I’m posting this is I want to thank you guys for writing some of the best articles that Anandtech has ever written. I read every page and enjoyed the whole thing. Keep up the great work guys and I look forward to reading more (especially about Nehalem and anything relating to AMD’s future architecture).
Also, is GDDR5 coming to the 4850 ever? If so, maybe it would be a drastically better buy.
Thank you,
drpepper128
Clauzii - Wednesday, June 25, 2008 - link
Damn, You R pissed!! :OOK, get some sleep and wake up smiling tomorrow, knowing that It's ATI needing to raise prices - - - and go get that 4870 :))
Clauzii - Wednesday, June 25, 2008 - link
OH, " ... that It's NOT ATI needing to ... "BTW: I actually read the review as pretty neutral, making a hint here and there that the further potential of the HD4870 is quite big :)