Specifications of ATI's upcoming RV870 have popped up at German websites and it's said that this DirectX 11 card may be released as soon as July 2009. Bright Side of News has all the details and claims the RV870 is a 40nm DirectX 11 tweak of the RV770 architecture, it seems this chip may actually have a quite large die. The RV870 is expected to have 1200 cores and a computing power of 2.16 teraFLOPS, while the higher clocked dual-GPU version will offer 4.56 teraFLOPS if these rumors are to be trusted.
The RV870 chip should feature 1200 cores, divided into 12 SIMD groups with 100 cores each [20 "5D" units], while RV770 was based on 10 SIMD group with 80 cores total [16 "5D" groups consisting out of one "fat" and four simpler ones]. Thus, it is logical to conclude that when it comes to execution cores, not much happened architecturally - ATI's engineers increased the number of registers and other demanding architectural tasks in order to comply with Shader Model 5.0 and DirectX 11 Compute Shaders. The core is surrounded with 48 texture memory units, meaning ATI is continuing to increase the ROP:Core:TMU. For the first time, ATI is shipping a part with 32 ROP [Rasterizing OPeration] units, meaning the chip is able to output 32 pixels in a single clock.
When it comes to products, ATI plans to launch four parts: Radeon HD 5850 and 5850X2 in more affordable pricing bracket and HD5870 and HD5870X2 for the high-end parts. While there were no clocks for the Radeon HD 5850/5850X2 parts, alleged clocks for HD5870 and HD5870X2 reveal that for the first time, an X2 part is clocked higher than a single-GPU part. Was this a requirement of SidePort memory interface, we are not aware atm.
HD 4870 X2
HD 5870 X2
2x 1.2 teraFLOPS
2x 2.28 teraFLOPS
Some details about NVIDIA's GT300 were leaked yesterday, that chip will reportedly feature a whole new architecture with 512 MIMD cores but it's expected to arrive several months later than ATI's RV870.