Measured was the time it took the Z64 to load Perfect Dark into its RAM, from the moment the A Button was pressed until the bar in the OSD reached 100%.
Results:
4GB 2,5" laptop HDD: 47,4s ~0,67MB/s
1GB CF Sandisk Extreme III 20MB/s with Dealextreme CF to Ide adapter: 31s --> ~1MB/s
2GB SD Sandisk Ultra II 10MB/s with SD to Ide adapter from conrad.de: 31,3s --> ~1MB/s
2GB CF SanDisk Extreme III with CF to IDE adapter: 31s
512MB CF SanDisk with CF to IDE adapter: 31s
1GB Kingston MicroSD (Made in Japan) with SD to CF Adapter and CF to IDE adapter: 34s
As you can see, there are no benefits in using the highspeed flashcards(133x or even 300x) compared to normal ones.