I know that Xilinx do a range of RAD-hardened FPGAs which are designed for the rigorous challenge of space travel. Besides FPGAs there are a range of RAD hardened components which are designed to deal with the high levels of exposure.
There is some detail about the computing power of the device on the wikipedia page, the processor is a BAE systems RAD750 with 400MIPS! http://www.baesystems.com/article/BAES_077441/bae-systems-hardware-lands-on-mars-aboard-curiosity-rover
I know that the rover is powered by a 'nuclear battery' which is a plutonium isotope thermopile, this could also be used to heat the rover in the harsh Martian winters, unlike previous rovers this one is designed to operate during winter, which is the reason for the radioactive constant power source.
Sanjib, we are in touch with JPL to get more details on the FPGA design for Curiosity. Stay tuned.
Meanwhile, we see India is planning a Mars probe:
Thanks for sharing more information on the electronics of Curiosity. How is the electronics protected from the harsh environment on Mars. Are these electronic control cards kept inside a climate controlled chamber inside Curiosity? Any information on who the FPGA manufacturer is?