As much as I like my Emu 1820m, their usb interfaces don't seem too hot for me. The biggest issue I've been reading about is their inability to use WDM and ASIO simultaneously, a deal killer if you've gotten used to their pci interfaces. One thing to check for would be your usb chipset. We've been encountering some chipset issues (as well as some other operating issues) over at the Unofficial Emu forums (productionforums.com) where I moderate as well.