[LAU] USB has power even when PC is shut down?

I upgraded my home PC to AMD64 dual core and the motherboard is ASUS
M2N-E Socket AM2 NVIDIA nForce 570 Ultra:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131022

I've an M-Audio Midisport 4x4 MIDI box connected to the PC via USB.

On my old system (AthlonXP 2000, I forgot what kind of motherboard),
when the system was turned off, everything went dark.
But on the new system, the Midisport stays powered up even after the PC
is turned off. I can tell it's up because the green LED is still
blinking. The PC really is off, the disks are stopped, no moving parts
move, everything is cold.

Well, I guess this is more of a hardware question, but still, what's the
deal with USB on these new motherboards? Is the bus still powered even
after the system is turned off?

-- 
Florin Andrei
http://florin.myip.org/
_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-user