I had a customer report that on his XP machine with i7 CPU (sic), the SSE3 check fails. I'm using SystemStats::hasSSE3().
Microsoft docs indicate that PF_SSE3_INSTRUCTIONS_AVAILABLE is not supported on XP.
It looks like on XP you can get the SSE3 availability directly from the CPU ID. There is a discussion here:
http://stackoverflow.com/questions/6121792/how-to-check-if-a-cpu-supports-the-sse3-instruction-set