Figure 1 – Die photo of CELL processor with block diagram overlay
Figure 1 shows the die photo of the first CELL processor implementation with 8 SPE’s. The sample processor tested was able to operate at a frequency of 4 GHz with Vdd of 1.1V. The power consumption characteristics of the processor were not disclosed by IBM. However, estimates in the range of 50 to 80 Watts @ 4 GHz and 1.1 V were given. One unconfirmed report claims that at the extreme end of the frequency/voltage/power spectrum, one sample CELL processor was observed to operate at 5.6 GHz with 1.4 V Vdd and consumed 180 W of power.
As described previously, the CELL processor with 8 SPE’s operating at 4 GHz has a peak throughput rate of over 256 GFlops. To provide the proper balance between processing power and data bandwidth, an enormously capable system interconnects and memory system interface is required for the CELL processor. For that task, the CELL processor was designed as a Rambus Sandwich, with Redwood Rambus Asic Cell (RRAC) acting as the system interface on one end of the CELL processor, and the XDR (formerly Yellowstone) high bandwidth DRAM memory system interface on the other end of the CELL processor. Finally, the CELL processor has 2954 C4 contacts to the 3-2-3 organic package, and the BGA package is 42.5 mm by 42.5 mm in size. The BGA package contains 1236 contacts, 506 of which are signal interconnects and the remainder are devoted to power and ground interconnects.
Discuss (6 comments)