ATI Radeon HD 4850 Preview: AMD Delivers Performance for the Masses

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.