Stack overflow machine dependent?

Hello, I compiled a Haskell 98 program using ghc 6.2 -O and ran the executable, using main +RTS -H256m -s, on two similar computers: PC 1: Athlon 1400, 512MB, Windows XP Prof SP2 (successful termination) PC 2: Athlon XP 1800+, 512MB, Windows XP Prof SP2 (stack overflow) The program runs successful within 1MB of stack on PC 1, but it exits with a stack overflow error on PC 2. Has anyone else observed such behaviour using the same binary, and similar computers? I'm curious of what might trigger the stack overflow. The program itself is partially generated and large, so I'll omit it for the time being. Cheers, Arjen