Radeon 4800 Final Thoughts

There's a lot to like about the new Radeon HD 4800 series of products. To begin with, 800 cores is nothing to scoff at; even if they aren't nearly as efficient as they sound. CrossFireX scales performance very well, and for the first time actually makes multi-card setups worth the money. The most likable part is pricing: As of April 2009 the Radeon HD 4850 currently sells for $99 after rebate, which forces NVIDIA to drop the price of their GeForce GTS 250 (re-labeled 9800 GTX+) to meet with the competition. When ATI launched the Radeon HD 4870 at $300, NVIDIA had to answer back by dropping the GTX 260 to a more affordable price. The Radeon HD 4870 now sells for as low as $134.99 after rebate, making it difficult for the GTX 285. But that's where everything becomes unclear, and the value of ATI's latest product comes into question.

Here's why clarifying how the value has become so tricky is difficult to define. The initial interest in a product like the Radeon HD 4850 lies in the fact that it competes head-on with the GeForce GTS 250 (9800 GTX). But now that they are both priced roughly the same, value takes on a new dimension. In each and every test I conducted, the Radeon HD 4850 kept up with the GeForce 9800 GTX but never outperformed it (until 4x AA was added to Crysis). This would be the main reason why I see value becoming more of an issue outside of video game performance. The GeForce 9800 GTX+ offers HDMI, and so does the Radeon HD 4850. Both offer essentially the same exact sub-features down the line, except for when it comes to multi-card configurations; which is where the CrossFireX configuration really comes to shine.

I am very much aware that NVIDIA offers SLI just like ATI offers CrossFireX, but what I'm talking about is multi-card compatibility with motherboards. AMD Didn't exactly impress the world with Phenom, and thus the world hasn't jumped onboard to use their processors. Instead, Intel scooped up a large share of the consumer base with their P35/X38/P45/X48 chipsets (all launched within about ten minutes from each other). But here's my point: ATI still wins. All of these Intel motherboards, along with all of the AMD motherboards, offer CrossFire support exclusively. NVIDIA is left holding their own hand, because only select few Intel X58-based motherboards are expected to combine AMD's CrossFire technology with NVIDIA's SLI.

I'm not entirely sold on everything that the chipmakers would like for us to believe. I think it's sometimes worth questioning the wisdom, and in this regard I find that AMD is trying to pull one over on consumers by describing their RV770 to have 800 scalar processors. The reality is that ATI's 800 stream processor cores do not compare 1:1 against the competition, especially since the GeForce 9800 GTX can outperform the Radeon HF 4850 with only 128 shader cores. So despite what ATI would like to market, scalar processors they are not as they function exactly like vector processors would. With 800 processor cores residing in five bank location, each series of 5 processor cores process only one vector unit at a time - even if that vector doesn't need to use all five processor cores. 800 Cores are there, but they are far from the efficiency level seen by the competition.

My final thoughts on the 4800-series is where the Radeon 4850 and 4870 come up short. They're both great products just so that we're clear, but for a 55 nm process there's a lot missing from the RV770's arsenal that really should be there. I consider efficiency at the very start of this list, and even though my first lesson on the relationship between die process size and energy efficiency came from Mr. Jen-Hsun Huang, President of NVIDIA, I later researched this through my own testing and discoved that he was correct: reduced die process does not equal increased energy efficiency. Obviously this phenomenon holds up very well against the power consumption results I've tested for this review.

ATI's memory bus architecture also has me questioning their efforts. NVIDIA can produce a 512-bit memory bus making a 1:1 ratio of memory to interface (512MB @ 512-bit), so it's just a little disappointing that ATI did not do the same for their Radeon HD 4870/4890 (which both use GDDR5). Perhaps if I lower my expectations on improvements towards technology, I could accept a 256-bit Radeon HD 4850, but if you're going to make GDDR5 your marketing headline then perhaps you should also do something to match the technical achievements found in competing products. Notwithstanding, memory bandwidth is far from being saturated by today's gaming software (and hardware interface limits), and so my complaint is really more of a moot point, but it still stands to reason that AMD missed an opportunity here.

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