3DMark
3DMark is the latest version of this hugely-popular synthetic benchmark. Making use of DX11 features such as tessellation, compute shaders and multi-threading, it provides modern-day results and is available as a free download.
The chasm that exists between high-end and mid-range cards has done well to go unfilled 'til this point. Slotting in rather nicely, the R9 380X does a reasonable job of filling the void between GTX 960/R9 380 and GTX 970/R9 390.