The primes were independently verified in 13 days and 5 days respectively by Tom Duell (Burlington, MA, USA) and Rob Giltrap (Wellington, New Zealand), both of Sun Microsystems , using the Mlucas program by Ernst Mayer of Cupertino California USA. The verification ran on 8 dual-core SPARC64 VI 2.15Ghz CPUs of a Sun SPARC Enterprise M5000 Server and 4 quad-core SPARC64 VII 2.52GHz CPUs of a Sun SPARC Enterprise M8000 Server in Menlo Park, CA, USA.

Source: Gimps