So guys i was thinking about getting myself a usb block erupters and mine, any idea what the hashrate of a single erupter is in comparison with r290 graphics card?
You are looking at the wrong coin to use a block erupter.
http://www.quarkcoins.com/mining-quarkcoin.htmlBy all means, mine quark on your CPU while mining some other sha256 coin on the block erupter.