Transistors rx480-5,700 million vs 390x-6,200 million
Bus Width 256 bit vs 512 bit
so your 480 is approximately equal to the 280x and will never reach the level of 390
So what ?
Pitcairn have 256 bit bus too, but only 100-120 H/s
Fiji have 4096 bit bus, but it does even less than Havaii.