Couldn't help it. 5Gh/s is not 5000 Mh/s. Rather it is 5120Mh/s. Basic computer science:

1 Bit = Binary Digit
8 Bits = 1 Byte
1024 Bytes = 1 Kilobyte
1024 Kilobytes = 1 Megabyte
1024 Megabytes = 1 Gigabyte
1024 Gigabytes = 1 Terabyte