I have a 8750m 2gb ddrs with an i5-4200m
-Watch Dogs +25 FPS medium.
-BF4 +25 High (directX)
-AC4 +20 (High - no anti aliasing).
-GTA 5 there's news about enhancing the PC version so don't know yet the final requirements
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-And as for Mantle it's now supported for mobile GPUs (GCNs) like the 8750m, tried it with Thief (21.3 Avg fps at high) and BFH (but it is not optimized yet as it's still a beta :X)
Goodluck
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