Xilinx recently announced the architectural details of its new FPGA family, the Virtex-4. As explained in the July 2004 edition of “Inside DSP,” the Virtex-4 family includes three “platforms” that feature different ratios of reconfigurable logic, multipliers, and other features. These platforms give Virtex-4 users freedom to choose a feature mix that is best for their applications. For example, all three platforms include a device with roughly 60,000 logic cells. The LX “logic” device contains 64 hard-wired 18-bit multipliers and 360 Kbytes of hard-wired memory. In contrast, the SX “signal-processing” device contains 512 multipliers and 720 Kbytes of memory. The FX “full-featured” device—which includes two hardwired PowerPC cores—falls between the LX and SX devices in terms of multipliers and memory.
The features of the Virtex-4 FX are similar to those of the older Virtex-II Pro FPGAs. However, the Virtex-4 FX operates at faster clock frequencies, and the new family includes parts with higher capacities than any Virtex-II Pro. Although Xilinx has not yet released pricing for the Virtex-4 FX, BDTI anticipates that Virtex-4 FX devices will also be significantly less expensive than Virtex-II Pro parts with similar capacities.
Interestingly, the Virtex-4 LX resembles the competing Altera Stratix II family in most respects. However, Virtex-4 LX parts have fewer multipliers than Stratix II parts with similar amounts of programmable logic. For example, the Stratix II family includes a device that offers the equivalent of 60,000 logic cells, 310 Kbytes of memory, and 144 multipliers. As described above, a similar Virtex LX device offers only 64 multipliers.
Although Xilinx has not announced pricing for the Virtex FX, it has released pricing for a few LX and SX parts. These prices suggest that the Virtex-4 LX will cost somewhat less than Stratix II parts with similar capacities. In contrast, it appears that Virtex-4 SX parts will offer greater capabilities and higher prices than Stratix II parts with similar amounts of programmable logic. In 2005, BDTI plans to perform in-depth analysis to more accurately determine how these competitors stack up in the context of signal-processing applications. For more information, contact Jeremy Giddings (giddings@BDTI.com).
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