Most of the leaks are running on 16.5.2 driver version. If you take Tonga, double the ROPS, add 256 cores, clock it about 25% higher, and add a small boost due to a faster cache, the leaks basically reflect that.
What it does not reflect is literally any of the new logic hardware in Polaris. That discard accelerator doesn't run itself. It is operated by driver code which does not exist at all in current AMD drivers.
The launch drivers in reviewers hands right now, 16.6.2, are just the first draft of support for the new features of the architecture, and I don't think it would be that surprising if performance in some areas improved in excess of 10%.
A 10% higher FSU score based on arch improvements. Plus a 20% OC from 1266 -> ~1500 on the GPU and the known 12.5% OC on the VRAM. This alone puts the card at Fury X.
Why would production drivers out in public have beta driver code for an unreleased product? It just doesn't go in the build. There is no optimization or hardware support for Polaris right now in the leaks, since the reviews just that missing code in the new press drivers less than 24 hours ago.
I just don't see an AMD developer leaking it. And since all the leaks are right around the same level, differing in 1080 base vs 1266 boost clocks it seems, it is even more unlikely that one guy leaked it to multiple people with different builds. Occam's Razor, 480 drivers didn't leak.