AMD Fire Stream - Hardware

Hardware

The Radeon series graphics processors are 32-bit single-precision floating point vector processors. Due to the highly parallel nature of vector processors, these processors have had a huge impact in specific data processing applications. The mass client project Folding@home has reported speed improvements of 20 to 40 times using an R580-based graphics card.

The Radeon R580 core includes a total of 48 pixel and vertex shaders, which become parallel processors in floating-point calculations. The ATI FireStream add-on card uses the PCI Express x16 interface to provide 8 GiB/s bandwidth. The card is equipped with 1 GB GDDR3 local memory while the GPU runs at 600 MHz core frequency and 1.3 GHz memory frequency. The core has the ability to execute 512 threads simultaneously (Simultaneous multithreading, SMT), at a rated thermal design power (TDP) of 165 W. The main difference between the AMD FireStream and ordinary Radeon series video cards is that the stream processor on the FireStream lacks video output connectors.

The stream processing hardware comes with a hardware interface called THIN (Thin Hardware INterface), or Close to Metal (CTM, previously named Data Parallel Virtual Machine), to open the GPU architecture in addition to native instruction sets to program developers. This allows to direct control of the stream processors/ALUs and the memory controllers, and permits bypassing of the 3D API layer.

The AMD Stream Processing lineup saw an update to the latest GPU architecture (the Radeon R600) with the release of the latest-generation FireGL video cards on August 7, 2007, which are also capable of stream processing. The architecture was manufactured on the same 80 nm fabrication process node as R580, with more parallel processors and stream processing units. In addition, the maximum GDDR4 memory was increased to 2 GB, providing a maximum of 128 GiB/s of memory bandwidth. The R600 XTX core-based FireGL products released (FireGL V8600 and FireGL V8650) consume more power than the first-generation ATI FireStream, with rated TDP of under 225 W and over 255 W respectively.

The second generation, the AMD FireStream 9170, is based on the RV670 core and is constructed using a 55 nm fabrication process. It features industry's first hardware-based support for double-precision floating-point numbers, asynchronous DMA (giving the stream processors and onboard memory the ability to exchange data without CPU intervention), memory export functionality, and reduced power consumption (less than 150 W with 2 GB GDDR3 memory onboard on a PCI-E 2.0 interface, providing 16 GiB/s device I/O bandwidth).

The latest generation of products in the AMD FireStream line is FireStream 9250 and 9270. The AMD FireStream 9250, announced on June 16, 2008, is based on the RV770 core and is manufactured using 55 nm fabrication process. It features 1 TFLOPS of raw floating-point power on single-precision operations, 1 GiB of GDDR3 memory and a single-slot cooler. While the other variant, the AMD FireStream 9270, announced on November 13, 2008, also features the RV770 core but with a higher floating point operation performance at 1.2 TFLOPS peak, 2 GB of GDDR5 memory and a dual-slot cooler.