Cross-loads are harder for a PSU to deal with because voltage is being concurrently applied to different rails at one time. Think of it as loading up your CPU, graphics and peripherals all in one go - a worst-case scenario.
Cross-load 1 puts almost all of the capacity down the throat of the minor lines while stressing the 12V line(s) with a couple of amps. The reverse is true of cross-load 2.
If you don't see <4.90V then we deem it to be a very good supply; SilverStone's is.