> even differences between an Intel i5 and Intel i7 pile up

i5 and i7 are terms which lack precision. Are you seeing different results for the same operations on the same arguments in the same order across an i5 and an i7 with the same core architecture?

Regardless, it would be great if you have examples of operations that have different results on different processors; my expectation was that I could expect same width, same operation, same arguments to provide the same result across most x86 processors (early pentiums not dividing properly and maybe more variance in the socket 7 days where there were so many vendors). Most of the issues I've seen documented were not running the same sequence of operations especially around 80-bit floats on x87 if something spills to a 64-bit double in memory. All that said, I prefer to deal in integers whenever possible, I know the edges of floating point are sharp, and I'd rather not be cut.

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