lentildude

I have a generic dm-134 4 ch dvr. I have a 320gb hdd in it and even if I select disable recording on all channels the hdd led is on I can hear hdd spinning. Does the hdd always have to run? Can it not powerdown and only spinup on motion detection. (I guess not for the prerecord function to work). Thinking it would be great if it could write to usb flash memory or perhaps better to buy a solid state drive to save power.