I just received my Vega 56 a few days ago, done some testing over the weekend and wanted to share my thoughts with you.
overall its positive, performance is very good, but the main issues i have relate to the drivers that are still buggy, i had the white noise screen, blank screens, some random crashes, and there is bug with radeon relive that maintains 100% gpu load even after existing the game and the card should normally go back to idle, the work around for this is to manually turn relive off then on.
I tested the card at stock, turbo and undervolted with overclocked memory and increased power and fan speed.
difference between balanced and turbo was not much, however with undervolting and overclocking the memory along with power offset and custom fan profile it makes a big jump in performance.
the results were as follows:
1- CPU OC 3.7GHz and GPU balanced
Time spy: 6232
graphics 6042
CPU 7584
http://www.3dmark.com/spy/2357279
Avg clock 1325
peak Temp 64
2- CPU OC 3.7GHz and GPU turbo
Time spy: 6402
graphics 6240
CPU 7515
http://www.3dmark.com/spy/2357326
Avg clock 1400
peak Temp 70
3- CPU OC 3.7GHz and GPU undervolted 1075-1100, HBM 945, power +50%
Time spy: 7006
graphics 6908
CPU 7620
http://www.3dmark.com/spy/2357466
Avg clock 1540
peak Temp 64
4- CPU OC 3.7 and GPU balanced
Fire strike: 15218
graphics 19013
physics 18483
combined 5510
http://www.3dmark.com/fs/13581529
Avg clock 1310
peak Temp 71
5- CPU OC 3.7 and GPU turbo
Fire strike: 15581
graphics 19752
physics 18992
combined 5462
http://www.3dmark.com/fs/13581446
Avg clock 1350
peak Temp 71
6- CPU OC 3.7 and GPU undervolted 1075-1100, HBM 945, power +50%
Fire strike: 16794
graphics 22202
physics 19045
combined 5591
http://www.3dmark.com/fs/13581352
Avg clock 1535
peak Temp 68
Finally a video showing actual gaming performance:
https://youtu.be/bTyLEwnFca8