TstRDTSC is the only safe tester of RDTSC instruction.
It must be executed under Windows 9x.
You can run it even if you have 386 CPU only.
Bit TSD of CR4 register is cleared (only if it was set before testing).

That's because there are three groups of CPUs (CR4.TSD=0) :
A) RDTSC works fine in V86 mode
B) RDTSC generates exception 13 in V86 mode (AMD, some (old?) Pentiums,..)
C) RDTSC is not supported (486-)

Messages:
>>>>> Instruction RDTSC is
-- supported                                    (your CPU belongs to group A)
-- supported, but disabled in V86 mode for ever (your CPU belongs to group B)
-- not supported                                (your CPU belongs to group C)



EliCZ (elicz@email.cz)  01/06/1999  (mm/dd/yyyy)