Can two identical Windows computers produce different calculations?

Can you explain better what kind of calculation  are you doing on the computers? Thanks

Why Calculations Differ

Floating-Point Arithmetic: Computers handle decimals using approximations defined by the IEEE 754 standard. Small rounding errors happen and can add up over long calculations.

Order of Operations: Multi-threaded or parallel programs can process math tasks in a different order on each machine. Changing the order changes how rounding errors accumulate.

Hidden Hardware or Library Differences: Even "identical" PCs might have different CPU microcode revisions, BIOS versions, or math library versions (like BLAS or LAPACK) that handle instructions differently.

Uninitialized Data: Software that reads random memory left by other programs can behave unpredictably or calculate different values if memory states differ

Should You Trust One Over the Other?

For Standard Tasks: Both results are equally correct and reliable for everyday apps, gaming, or office work. The tiny differences do not affect normal use.

For Scientific or Financial Modeling: Minor variations are normal. You should rely on numerical stability algorithms rather than trusting one physical machine over another.

Yes, two computers with the same hardware and software can sometimes produce different results, although this should not normally happen for a deterministic calculation.

The difference may come from several things, such as different CPU behavior, compiler settings, floating-point calculations, different drivers, system updates, or even hardware problems. If the calculation uses multiple CPU cores or threads, the order of operations can also affect the final result, especially with floating-point numbers.

I use Linux, but the same general idea applies here. I would first make sure both machines are running exactly the same version of the software, using the same input data and settings. Then I would run the calculation several times on both computers and compare the results.

If one computer consistently gives a different result, I would check the RAM, CPU stability, temperatures, and storage, and also look for any software or configuration differences.