ATI Radeon HD 4850/4870 Performance Preview

Today is a pretty exciting time if you’re in the business of following 3D graphics. Not only are we seeing DirectX 10 games that are capable of dishing out graphics that put the latest consoles to shame, we are also reaching a point where graphics cards are being tasked to handle duties beyond conventional graphics such as video encoding in the consumer space, and financial analysis for businesses. But as positive as all this is, there’s something even more exciting that’s got us absolutely giddy right now -- the competition between ATI and NVIDIA is hotter now than it has been in well over a year.

If you’re skeptical of this last statement, just look at what happened last week as proof. As a result of the Radeon HD 4850’s tremendous price/performance ratio, NVIDIA was forced to slash prices on their entire family of GeForce 8/9 graphics cards. The GeForce 9800 GTX went from being a $300 card on Thursday, to selling for $199.99 on Friday! NVIDIA also cooked up a brand new GeForce 9800 GTX+ SKU to take on the new Radeons that will arrive in July. This is all wonderful news if you’re a gamer who is in the market looking to upgrade: building a powerful rig for gaming just got much cheaper as a result.

So how did we get here? Let’s rewind a bit shall we?

After experiencing repeated delays with each next-generation architecture (first R520, then R600) ATI began to realize that designing these massive, cutting-edge GPUs that were needed to service the high-end market was becoming less practical. They came to the conclusion that they were reaching a point of diminishing returns where the resources that were being thrown into these high-end GPUs weren’t being fully realized: by the time software came out that really exploited the capabilities of the hardware, the GPU was outdated. In addition, there were cases where functional units inside these pricey GPUs had to be disabled and/or clock speeds reduced in order to bring lower-priced SKUs to market at specific price points. Examples of this include the Radeon X1800 XL and ATI’s Radeon 2900 Pro/GT, which were based on ATI’s R520 and R600 GPUs respectively.

Rather than devote the hundreds of millions in R&D required to bring another large GPU to market, they decided to take the opposite approach for RV770; they would start with a much smaller, more cost effective midrange GPU design, and scale it up and down to meet the needs of different markets. Their belief was that a less complicated GPU design could be brought to market faster than a large GPU, and at price points that a wider group of people actually want. ATI’s engineers were given very specific transistor and die size budgets to shoot for, while at the same time they were still tasked to achieve certain levels of performance: at least double the performance of R600 was the goal.


But did they accomplish this goal? If you saw the Radeon HD 4850 benchmarks last week, you already know the answer is a resounding YES! In this article, we’re going to take a quick look at the new architecture, and then a deep dive into some benchmarks. We’re not only going to examine 4xAA performance (one of R600’s weak points), but also 8xMSAA and ATI’s custom filter AA modes as well.