Dan you are correct is speed limits on USB 2.0. Limited by USB port all I did was simply installed USB drive inside over external. I also recommend the Time capsule over the extreme It is possible with the new Extreme to install a pair of USB drives and still be able to use the USB port for external devices From my box of parts. Only for advanced user Mods (1) One laptop power supply removed the plastic case $10.00 (2) One Buck unit to supply power to drives $3.50 12vx5v @ 5amp (3) One powered USB hub $4.50 4 port (4) Two WD USB portable drives 1T each used value $50.00 (5) Lift the two center pins on USB port on the Extreme hard wire the two center pins of Extreme USB to one of the USB ports of Hub not the primary (6) Primary pins from hub back to the motherboard of extreme two center pins only. Note the primary pins of hub normally be plugged into USB port now hard wired to Extreme motherboard where USB pins were lifted observe polarity of both center pins (7) When finished two hard drives 2.5 inside the...

Install a WD portable HD 1T wire to USB port works well for Time machine. or a NAS. Remember not to us the external USB if you install the HD internal.