ATI Radeon HD 5800 Family
Twice the Horsepower
The new ATI Radeon HD series has valid claims to the number 5 in the generation number but of course, like every modern GPU, the RV870 has inherited a lot of traits of its predecessors RV770 and RV790. Thus, the new generation of ATI top-performance graphics cards has got the name of Radeon HD 5800. At the time of the announcement there are two products in it: the flagship Radeon HD 5870 that enables all of the RV870’s resources and the less advanced Radeon HD 5850 that seems to be based on those graphics processors that did not pass the frequency check and/or have a few defective subunits. The recommended price of the new products is $399 and $299, respectively. Let’s compare their specs with those of the best solution from the previous generation.
First off, the new GPU developed by ATI is mind-bogglingly complex incorporating over 2 billion transistors. At this scale, even Nvidia’s G200 looks like an example of simplicity. What is even more incredible, the senior model’s core is clocked at 850MHz. These miracles have been made possible by the 40nm tech process without making the core too large. The RV870 is even smaller than the G200b!
The memory subsystem specs are also impressive due to chip memory subsystem optimization and improving of the GDDR5 frequency specifications. ATI Radeon HD 5850/5870 has lower peak memory bus bandwidth than the GeForce GTX 285 because of the relatively narrow 256 bit bus. Perhaps the single Radeon HD 5870 will be inferior to dual-GPU solutions of the previous generation in highly demanding games and at extremely high display resolutions but this supposition is yet to be confirmed in practical tests. As for the previous-generation single-chip flagship solution, the improved internal structure of the newcomer has every chance to leave it far behind.
Then, the Radeon HD 5870 is the same as the Radeon HD 4870 X2 in terms of potential computing power as well as texture and raster processors, but its GPU works at a higher frequency. Theoretically, the new flagship’s performance is going to match that of the Radeon HD 4870 X2 or be slightly higher because of internal chip optimizations.
Besides the obvious architectural improvements, the new ATI Cypress graphics chip has some principal differences from the predecessors: this is the world’s first graphic core to support DirectX 11. Considering the upcoming Windows 7 release, this API is likely to become a de facto industry standard, so AMD has ensured an advantage over Nvidia that does not yet offer any DirectX 11 compatibles. Besides a few obvious innovations in the 3D part, such as tessellation and more advanced pixel or vertex shaders, DX11 has a number of other new features:
- Multi-threaded rendering: should allow using multi-core processors more effectively for 3D imaging.
- Unified GPGPU support: unified GPU programming standards – DirectCompute and OpenGL – encourage a lot of developers to use graphics chips for physical, AI or any other calculations. We see a lot of software applications today that work exclusively with GeForce/CUDA.
- Enhanced full-screen antialiasing algorithms support providing a performance boost.
- A number of other innovations increasing the general performance and efficiency of the graphics subsystem.
Although Nvidia suggests that DirectX 11 support will not be a decisive factor in favor of a new graphics card (see this story for details), but it really looks like a poor excuse to us.
Summing it up, the new ATI Radeon HD 5000 graphics card family boasts huge potential indeed. But before we proceed to measure its extent, we will scrutinize the RV870 architecture for any changes over the RV770/790.