Maybe the perl hackers (as apposed to the Perl hackers) can correct me: your typical integer (x86 arch) is going to be 32bits. time returns an integer, and 1000 is an integer, so perl's going to return the results as an integer too. But the largest number a signed integer can express is roughly 2 billion. Time just spilled over into the 1 billions fairly recently. So the result is overflowing, giving you the "inaccurate" answer.

See how Math::BigInt works out for you.

-Ducky