Which GPU shall I order? PULSE RADEON RX 570 / NITRO+ RADEON RX 580 4GB / NITRO+ RADEON RX 570 8GB

I tend to buy the NITRO+ RADEON RX 570 8GB but I need a recommendation before I spend thousands of $. Here comes the prices, hash-rate and power consumption = performance.

PULSE RADEON RX 570 (220$)

GPU/memo clock: 1130/2050
Ethereum: stock 24 Mh/s ; modded bios + oc 29-29.5Mh/s (Hynix)
Power Usage: N/A

NITRO+ RADEON RX 580 4GB (250$)

FOR THE 8 GB VERSION
GPU/memo clock: N/A
Ethereum: stock 24 Mh/s ; modded bios + oc 30.2 Mh/s
Power Usage: 142w / 77.5W

NITRO+ RADEON RX 570 8GB (280$)

DATA FOR 4 GB VERSION
GPU/memo clock: 1130/2050
Ethereum: stock 24 Mh/s ; modded bios + oc 29-29.5Mh/s (Hynix)
Power Usage: N/A

I think the hash-rate is not very different from 8 to 4 gb version so the data could be applied. Correct me if I am wrong.

Thanks for helping me!