Try to wait if you can but I have a vega 56 and it works great on 1080p 144Hz with a decent undervolt to keep temps and power usage in check.
Sticking with an Ubuntu-based distro would be best for you so that's a good choice
I've seen Vegas on ebay with the morpheus cooler installed, though it is rare.
There's 2.5 slot ones as well
My poor old 3570k is suffering from all these patches :(
I mean it won't hurt waiting a week for official news on NAVI
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