Launch of nVIDIA’s GeForce GTX 280 brought a huge enthusiasm in last two months, but it already begun to fade. The main “culprit” is ATi which showed to all of us that even when hard times come they are continuing with good work as if competition isn't a problem and as confirmation of their efforts we got incredible new generation of graphics cards. The whole story started with great Radeon HD 4850 and continued with HD 4870 that had GDDR5 memory. After great critics for these two GPUs, ATi was aware that they shouldn’t stop there, if they want to overthrown nVIDIA from the top performance throne. And they did it…

You can bet that ATi learned lessons with Radeon HD 3870X2 and introduced Radeon HD 4870X2. ATi really did great job, so great that several former nVIDIA exclusive brands like Gainward start with production of graphics cards based on ATi GPUs, while many of them for the first time will take in consideration that possibility. These new actions show not only that ATi can compete with nVIDIA but also how much nVIDIA is threatened by ATi.


Same, but different

When I got HD 4870 X2 into hands, I must confess that it looked to me like I was holding 3870X2, because these two cards are almost identical. The main difference in their looks is color of circuit board. ATi wanted to represent 4870 X2 as really tough piece of hardware so they colored a circuit board in black and to be frankly it truly looks great in combination with black colored cooling solution. If you read our article about ATi Radeon HD 3870X2 you can see that design of cooling solution is identical, which means that cooling profile for HD 4870 X2 is made mostly from cooper that covers also memory modules.

On the back of circuit board is plastic plate that covers rest of memory chips and also makes card extremely firm, regardless on large dimensions and weight: 1120grams (GTX 280 weighs 880grams). Even though cooling solution has great design it can barely handle two hot GPUs, memory and PLX chip that are below it. Temperatures are pretty high and more than often they exceed 100°C under load in these hot August days. With air conditioner set on 25°C situation becomes bearable but temperatures are still high, those 100°C are still achievable even with air conditioner on. So, pay attention on size of your case, smaller the case higher will be temperatures and that could be a real problem.

2 x R770 = R700

Funny mathematics, but equation is simple, right? On one PCB are two Radeon HD4870 that use second generation of PLX chip for communication with bus twice faster than two R670 had on Radeon HD 3870X2, which means that new PLX chip is PCI-Express 2.0 compatible. One more improvement in communication between two GPUs is XSP (CrossFire Sideport) that enables additional communication between two GPUs on HD 4870X2. This technology isn’t enabled at the moment because ATi claims that possibility like this isn’t necessary for now. We only can conclude that if even in theory exist possibility for better performances there is no logical explanation for disabling that possibility completely, except if something isn’t quite right.

As far as characteristics of HD 4870X2 are concerned, if we just double the specifications of HD4870 we’ll get the following. Card has 1600 stream processors; you must admit that this is very impressive. Also card has 32 Raster Operators and 80 texture units effectively. Although there is 2GB of memory in physical sense reality is that you have two Radeon HD 4870 with 1GB memory but that memory is not cumulative. Main memory characteristics are: GDDR5 memory signed by Hynix, chips are declared as 4Gbps (up to 1000MHz) i.e. provided memory bandwidth is up to 115GB/s. These characteristics definitely can justify self-confident ATi’s statement that this is the fastest graphics card at the moment. From multimedia improvements there is new audio solution integrated inside GPUs and ATi chose Realtek 8-channel solution which means that all models from HD 48XX series have capability of reproduction 7.1 sound through HDMI.


Performances

We could sum them all in just one word – phenomenal. This graphics card sets new standards for performances achieving much more than GTX 280 can reach. Still, everything isn’t perfect, in some situations HD 4870 X2 turned out as slower and biggest stumbling block for this card is definitely “notorious” Crysis, the most demanding game of today. In Crysis Radeon HD 4870 X2 has lower score than GTX 280 but that wouldn't bother us that much if we didn't expect the biggest difference between ATi and nVIDIA in that exact game. This can be explained by the fact that Crysis is “nVIDIA: The Way It’s Meant To Be Played” game that favors “greens”, but that certainly is no excuse. Also World In Conflict game that stands as really demanding game, gives advantage to competitor too. These scores leave a feeling of incompleteness because card failed where it shouldn’t. Still, for all rest results GTX 280 can eat HD 4870 X2’s dust. Maybe HD 4870 X2 will have guaranteed success no matter on Crysis. Or maybe we should wait for next version of ATi drivers?