I'd say your best bet is looking up the frequencies of the main processor/memory types (like Pentium) on Wikipedia, since they tend to give you some nice tables with an overview of their specs.
In the case of Pentium you get a very broad range (in time) of frequencies, which is probably what your after.
For memory, someone else will have to suggest a type or brand though you could look for things like DDR memory etc.
Downside: you'll have to create a graph like this yourself, though with Excel, that shouldn't be too hard. And in case you miss some years, just interpolate ;-) Moore's Law will keep you safe!