[jan-jaap]

I think upgrading the CPU and graphics is fine without a reinstall as both are from the same family (MGRAS for the graphics, both R10k for the CPUs). Now going from Extreme to IMPACT might involve a bit more work, but to my knowledge you can just upgrade different versions of IMPACT via a simple swap. Of course, I stand to be corrected here?

99.9% correct.

The very first Impact systems were Indigo2 High Impact, and came with "IRIX 5.3 for Indigo 2 Impact (09/95)". Three months later Solid and MaxImpact were introduced and with them "IRIX 5.3 for all Indigo 2 Impact". So if you were to swap a HighImpact for another Impact in this one version of IRIX, then it's not going to work. Guess who had that happen to him ...

Of course all of this information is 100% irrelevant for R10K systems because they run IRIX 6.2 or newer.