I can only think of scans of those magazines in the few places where scans of old computer magazines may be kept. I don't think there were standardised tests back then, i remember them too - charts comparing excel and 1-2-3 at some task and so on. The articles should also explain what the tests were doing. It all sounds a bit manual though, lots of looking through PDFs and so on

I guess one could re-construct them to have about the same effect, like updating 3000 spreadsheet cells or spellchecking a 200 page document in Word, but it would not be 100% comparable. My hope was that someone had or knew were to find a copy of the benchmarks files