Should I run my regression testing programs on both AMD and Intel chips?

Question

Right now I plan to test on 32-bit, 64-bit, Windows XP Home, Windows XP Pro, Windows Vista Home Basic, Windows Vista Ultimate, Windows 7 Home Basic, and Windows 7 Ultimate ... all with the latest service pack.

However, now I'm wondering if it's worthwhile to test on both AMD and Intel for all the listed scenarios above or would it be a waste of time?

Note: this is a security application for everyday average users.

Answer 1

My feeling is that this would only be worthwhile if you had lots of on-the-edge hand-coded assembly language or some kind of incredibly tight timings (which you're not going to meet with that selection of OS anyway).

If you're using off-the-shelf commercial compilers, then you can be reasonably sure they're going to generate code which runs on all the normal processors.

Of course, nobody could ever prove they didn't need to test on a particular platform, but I would think there are bigger causes of platform difference to worry about than CPU brand (all the various multi-core/hyperthreading permutations, for example, which might expose all your multithreaded code bugs in different ways)

Answer 2

Only if you're programming in assembly and use extended, vender specific instruction sets. But since AMD and Intel have cross-licensing agreements in place, this is more of an historic issue than a current one.

In every other case (e.g. using a high level language) it's the job of the compiler writers to ensure the code is x86 compliant and runs on every CPU.

Oh, and except the FDIV Bug Processor vendors usually don't do mistakes.