ATI Radeon HD 3870 & 3850: A Return to Competition
by Anand Lal Shimpi & Derek Wilson on November 15, 2007 12:00 AM EST- Posted in
- GPUs
Finally. We're finally getting somewhere interesting in the graphics industry. Although they're sure to return, the days of reviewing $600 graphics card after $600 graphics card are on hiatus, and instead we're reviewing a new class of mainstream cards with earth-shattering performance.
NVIDIA's GeForce 8800 GT kicked off the trend, in one fell swoop making almost all of NVIDIA's product line obsolete thanks to the high performance and low price tag (we'll talk about that last part shortly). But what we saw there wasn't a fluke, it was a preemptive strike against AMD, who have been hard at work on an affordable GPU of their own.
This new product, like the 8800 GT, would be aimed squarely at the $150 - $250 market segment, something both AMD and NVIDIA did a horrible job at with mainstream releases earlier this year (2600 and 8600 both sucked guys).
Introducing the RV670
AMD's two new graphics cards launching today are both based off a new GPU, referred to internally as the RV670. The basic architecture of the hardware is largely unchanged from R600; there has been some additional functionality added, and a great deal of internal bandwidth removed, but other than that this is very much an R600 based part.
The biggest news of this part is that it is fabbed on a 55nm TSMC process. This is a half-node process based on 65nm technology, giving AMD an advantage in die size (cost) and potentially clock speed and/or power.
Historically, AMD's RV series has been a cost cut version of their R series designed for lower end volume parts, and that's where RV670 started. Right of the bat, half the external and internal memory bandwidth of R600 was cut out. External bandwidth dropped from 512-bit to 256-bit, but AMD stuck with 8 memory channels (each dropped from 64bit to 32bit).
Internally, the ring bus dropped from 1024-bit to 512-bit. This cut in bandwidth contributed to a significant drop in transistor count from R600's ~720M. RV670 is made up of 666M transistors, and this includes the addition of UVD hardware, some power saving features, the necessary additions for DX 10.1 and the normal performance tuning we would expect from another iteration of the architecture.
Processing power remains unchanged from the R600; the RV670 features 320 stream processors, 16 texture units and 16 redner back-ends. Clock speeds have gone up slightly and memory speeds have increased tremendously to make up for the narrower memory bus.
The RV670 GPU is also fully PCI Express 2.0 compliant like NVIDIA's G92, the heart and soul of the GeForce 8800 GT.
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ChronoReverse - Friday, November 16, 2007 - link
I'll third that. The lines are great. Let's me know the resolution scaling quickly too.peldor - Thursday, November 15, 2007 - link
The line graphs are an improvement over the bar graphs. Good use of colors on these charts too.Anand Lal Shimpi - Thursday, November 15, 2007 - link
I think this is honestly one of the best ideas I've ever heard. If I were talented enough to make a good looking hand puppet...Take care,
Anand
xsilver - Thursday, November 15, 2007 - link
pfft. hand puppets,you need 3d virtual godzilla representing nvidia and 3d virtual king kong representing amd. BTW godzilla would win because it can shoot flames out of its mouth. :P
about the article - is it not feasible that when the price of the 8800gt drops to $220 or lower the 3870 just needs to drop to 85% of that mark? With the 3870 being on the smaller die process, they could afford it or at least try to?
Anand Lal Shimpi - Thursday, November 15, 2007 - link
ohhhhhk, I just said that I'm not talented enough to make a couple of hand puppets, you expect me to be able to create 3D models of reptiles and animate them? I picked text as a medium for my artistic expression for a reason - I'm not exactly artistic otherwise ;)The thought of a $220 8800 GT and a $187 3870 (and thus an even cheaper 3850) is just too much for my mind to handle at this point. I think it'll eventually happen, but not in the near term, these things are too new and both companies like making money.
Take care,
Anand
Anonymous Freak - Thursday, November 15, 2007 - link
Will you do a comparison on CrossFire performance, say, comparing two 3870s to two 8800GTs on X48 vs. 680i? Or even two 3870s on X48 vs. even ONE 8800 Ultra? If 3870 can really sell for $219, or 3850 for less than $200, two of them might well blow away an 8800 Ultra in $/fps terms, even worse than 8800 GT SLI does.Anand Lal Shimpi - Thursday, November 15, 2007 - link
Ask and you shall receive, I just added two new pages to the article - the new Page 10 tackles the CrossFire question.Take care,
Anand
wpapolis - Friday, November 16, 2007 - link
First off, great article! I still surf other web sites but when I read articles produced by Anandtech, they are usually more informative and better presented. Anand, you have a great sense of the relevant information to include in your articles and I do appreciate your effort.Just one small thing regarding CrossFire performance. I was a little disappointed when I read your comment ...
"Scaling looks pretty good from the Radeon HD 3850, however it's still not as good as what NVIDIA is able to achieve with the 8800 GT. NVIDIA consistently achieves about 11% better scaling from one to two GPUs than AMD."
You mentioned that scaling of the 3850's isn't as good as a 8800 GT. In this case, did you compared ...
2 x 3850's with 256MB per card
vs. 2 x 8800 GT's with 512MB per card?
If so, I would be interested in how well ...
2 x 3870's with 512MB per card compares.
I suspect that running a Crossfire configuration sucks up more RAM, so using a 256MB cards doesn't scale as well as using 512MB+ cards.
I know, I know, you didn't get 2 x 3870's, but maybe you can get one more now? Maybe one more page to this article?
Thanks again for your tremendous effort!
Bill
chrispyski - Thursday, November 15, 2007 - link
Nice crossfire chart. I know many people will be thinking about CF'ing the 3850's over a single high-end card (although I totally agree, it does not really work out well in the end)chucky2 - Thursday, November 15, 2007 - link
Those that could have waited for the 3850 and instead bought a 8600 or 2400/2600 are probably kicking themselves right now...Chuck