ATI Radeon HD 4850 Preview: AMD Delivers Performance for the Masses
by Anand Lal Shimpi & Derek Wilson on June 19, 2008 5:00 PM EST- Posted in
- GPUs
It's been one of those long nights, the type where you don't really sleep but rather nap here and there. Normally such nights are brought on by things like Nehalem, or NVIDIA's GT200 launch, but last night was its own unique flavor of all-nighter.
On Monday, AMD had a big press event to talk about its next-generation graphics architecture. We knew that a launch was impending but we had no hardware nor did we have an embargo date when reviews would lift, we were at AMD's mercy.
You may already know about one of AMD's new cards: the Radeon HD 4850. It briefly appeared for sale on Amazon, complete with specs, before eventually getting pulled off the site. It turns out that other retailers in Europe not only listed the card early but started selling them early. In an effort to make its performance embargoes meaningful, AMD moved some dates around.
Here's the deal: AMD is launching its new RV770 GPU next week, and just as the RV670 that came before it, it will be available in two versions. The first version we can talk about today: that's the Radeon HD 4850. The second version, well, just forget that I even mentioned that - you'll have to wait until the embargo lifts for more information there.
But we can't really talk about the Radeon HD 4850, we can only tell you how it performs and we can only tell you things you would know from actually having the card. The RV770 architectural details remain under NDA until next week as well. What we can tell you is how fast AMD's new $199 part is, but we can't tell you why it performs the way it does.
We've got no complaints as we'd much rather stay up all night benchmarking then try to put together another GT200 piece in a handful of hours. It simply wouldn't be possible and we wouldn't be able to do AMD's new chips justice.
What we've got here is the polar opposite of what NVIDIA just launched on Monday. While the GT200 is a 1.4 billion transistor chip found in $400 and $650 graphics cards, AMD's Radeon HD 4850 is...oh wait, I can't tell you the transistor count quite yet. Let's just say it's high, but not as high as GT200 :)
Again, we're not allowed to go into the architectural details of the RV770, the basis for the Radeon HD 4800 series including today's 4850, but we are allowed to share whatever data one could obtain from having access to the card itself, so let's get started.
Running GPU-Z we see that the Radeon HD 4850 shows up as having 800 stream processors, up from 320 in the Radeon HD 3800 series. Remember that the Radeon HD 3800 was built on TSMC's 55nm process and there simply isn't a smaller process available for AMD to use, so the 4800 most likely uses the same manufacturing process. With 2.5x the stream processor count, the RV770 isn't going to be a small chip, while we can't reveal transistor count quite yet you can make a reasonable guess.
Clock speeds are also fair game as they are reported within GPU-Z and AMD's Catalyst control panel:
That's a 625MHz core clock and 993MHz GDDR3 memory clock (1986MHz data rate). We've got more stream processors than the Radeon HD 3870, but they are clocked a bit lower to make up for the fact that there are 2.5x as many on the same manufacturing process.
| ATI Radeon HD 4850 | ATI Radeon HD 3870 | |
| Stream Processors | 800 | 320 |
| Texture Units | I can't tell you | 16 |
| ROPs | 16 | 16 |
| Core Clock | 625MHz | 775MHz+ |
| Memory Clock | 993MHz (1986MHz data rate) | 1125MHz (2250MHz data rate) |
| Memory Bus Width | 256-bit | 256-bit |
| Frame Buffer | 512MB | 512MB |
| Transistor Count | it's a secret | 666 million |
| Manufacturing Process | TSMC 55nm | TSMC 55nm |
| Price Point | $199 | $199 |
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docmilo - Thursday, June 19, 2008 - link
I browsed on over to the Egg and did a search on 4850. A whole bunch of cards popped up at $199.99 and one even has a rebate! I wonder how long until it stops saying "Buy Now" and goes to "Autonotify".chizow - Thursday, June 19, 2008 - link
You guys did a nice job of covering both the pros and cons of the 4850 and CF, showing some of the pitfalls of relying on multi-GPU solutions for performance. You also made mention that similar performance gains were seen long ago with the 8800GT.That said the 4850 is certainly a good part from AMD and there's definitely some very interesting things they've done with this card. You hinted at a lot of them with the architectural changes but there's a few other sites that hinted at some of the changes. Its clear ATI has drastically improved their memory controllers and cache design along with their render back ends for AA performance.
I think the real thing to keep an eye on though is how AMD managed to get near 100% scaling with CF. Extremetech hinted at improved memory controllers and a gpu communications "Hub" here http://www.extremetech.com/article2/0,2845,2320865...">http://www.extremetech.com/article2/0,2845,2320865... for improved performance between GPUs. I'm sure you guys will cover these improvements in detail in your complete review, but it looks like that hyper transport mechanism you alluded to.
MadBoris - Thursday, June 19, 2008 - link
Nice to see AMD staying competitive, plus keeping prices down.I think the days of me spending $400+ on a video card are behind me, atleast for the foreseeable future. You have to provide alot more than 10% performance increases for an extra $250 NVIDIA.
I'm rather surprised NVIDIA has not really capitalized on taking a huge performance lead and crown with all the AMD post merger dust settling.
I'm pleasantly surprised that AMD is continuing to excel with HW. If only they would bring back an AIW card, I'd buy one, but my current 8800GTS is not so outmatched that it is worth upgrading to anything this generation.
Good article Anand.
fungmak - Thursday, June 19, 2008 - link
Looking at the CF perfomance of other sites who used cat 8.6, IIRC were a lot better than the current AT results.Just wondering if there is an intention to update using cat 8.6?
derek85 - Friday, June 20, 2008 - link
I second this, I'm sure 8.6 came with some nice optimizations on 770s.DerekWilson - Friday, June 20, 2008 - link
we did not use catalyst 8.5 drivers.we used the very latest beta drivers ATI could get us.
Wirmish - Friday, June 20, 2008 - link
And did you use the Radeon HD 4800 Series Hotfix (6/20/2008) ?http://support.ati.com/ics/support/default.asp?dep...">http://support.ati.com/ics/support/default.asp?dep...
;)
Nighteye2 - Thursday, June 19, 2008 - link
The big question for the comparison between this card in CF and the GT200 will not be the classic framerates here - but the performance of games that use the GPU for part of the physics processing. The GT200 has lots of compute power to spare for physics, can 2 4850's in CF match that?FITCamaro - Friday, June 20, 2008 - link
With 800 shaders it wouldn't surprise me.Wirmish - Friday, June 20, 2008 - link
He talk about CF...So it's 1600 shaders !