3DMark, Doom
In the first two synthetic tests the amount of GPU memory is unimportant. Frequencies alone should dictate where the RX 460 cards benchmark amongst one another, and that is largely the case. The Gigabyte duo are off the pace because they are the only cards not to maintain their peak speed of 1,212MHz. Our logs show they average 1,140-1,160MHz, and this lack of consistentcy is down to insufficient power more than poor cooling.
However, opting for a 2GB card, which is cheaper to the tune of £30, may not always be the bargain that it appears to be on first glance. Doom, set to Ultra, shows that having half the usual framebuffer is painful from a performance perspective.