From a later page:
That's right, I still have my old PowerMac G5 Dual 2.5GHz (upgrade from my original 2.0 model). It's interesting to note that single threaded performance has only improved by 2.8x over that 2.5GHz dual G5 machine from around a decade ago.
And now a word from Amdahl:
The first thing I noticed while running this test is how much the workload can impact CPU core utilization. Even though I was dealing with a substantial 4K project, only portions could spawn enough work to keep all 12 cores/24 threads busy.
All that investment of billions and billions of dollars just to ... what? As the Red Queen said, "Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!" (Pulled from the wiki)