We recently had to support a customer who was unable to run XJTAG 3.1 on an older PC. It turned out that the processor in the PC in question did not support SSE2 instructions. During the development of v3.1 we upgraded the compiler we use to build XJTAG and it now uses these instructions to speed up execution. SSE2 instructions were introduced with the Pentium 4 in 2001 and were supported in AMD processors with their Opteron and Athlon 64 processors from 2003 onwards.
The following are examples of processors that do not support SSE2 and will not work with XJTAG:
- Intel Pentium III and earlier
- Intel Celeron processors based on Pentium III or earlier
- AMD Athlon XP and MP
- AMD Duron
- AMD Sempron
Note that any Intel or AMD processor released after 2003 will work fine with XJTAG and many released before that (e.g. Pentium 4) will too, so the number of machines this affects should be very small.