AMD Radeon HD 4870

Review

posted 7/17/2008 by John Yan
other articles by John Yan
One Page Platforms: PC
AMD’s recent video card activity has been getting them back into the game as their recent cards have shown they are taking steps in the right direction. Well, if the next two cards coming out are any indication, AMD is back in a big way and giving NVIDIA a big run for their money. AMD’s launching the ATI Radeon HD 4800 series of cards and we have a look at their two initial offerings in the ATI Radeon HD 4850 and the ATI Radeon HD 4870.

 
Card
First let’s look at what makes the 4800 series tick. For starters the cards are built on a 55nm fabrication process. Until recently with NVIDIA’s 9800 GTX+ launch, the ATI Radeon HD 4800 series were the only video cards to do this. As you know, smaller die equals less power needed and heat generated as well as decreasing the cost of producing the cards. AMD is able launch these cards at a very affordable price partially due to this.

The GPU codenamed R770 has been in the works for over two and a half years. Efficiency was one of the key goals and the engineering team worked really hard to make sure this was achieved with the R770. Deficiencies in the R600 line were studied, redesigned, improved upon, and incorporated in the R770. 965 million transistors, 800 stream processors, 40 texture units, and 16 render back-ends are just some of the processing power the R770 features.

Memory comes in GDDR3 or GDDR5 flavors. Data rates on GDDR5 can be up to 5X that of GDDR3 and 4X that of GDDR4. GDDR5 isn’t just about speed as there are new error correction mechanisms to help increase accuracy in calculations. There aren’t any other video cards using GDDR5 out there currently so the 4870 series of cards is the first out of the gate with it onboard. The 4850s use the lower rated GDDR3 and it helps keep the costs of the video card lower using the lesser performing memory. While the new NVIDIA card is using a 512-bit memory bus, the 4800s use a 256-bit memory bus. What the 4870 lacks in width makes up for with speed though with the GDDR5 ram. The faster ram will help compete with the bandwidth of a 512-bit memory bus in the NVIDIA cards.

TeraScale is what they call their new graphics engine. The name comes from the fact that there’s at least a processing rate of one teraflop or more. Compared to the ATI Radeon HD 3870, that’s more than double what the previous generation’s card is capable of.

DirectX 10.1 is supported of courses so you’ll be ready for the latest games on a Vista operating system. As with previous cards, CrossfireX technology is also in play allowing for multiple cards to be linked together for improved performance. We’ll be looking at Crossfire performance in a future article but recent reports state that you can get performance close to or surpassing NVIDIA’s single configurations of the GeForce GTX 260 and GeForce GTX 280 at a lower price point. Up to four GPUs can be linked together if your motherboard and power supply supports it.
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