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.
It's clear the R7 265 plugs the performance gap that was only partially filled with the Radeon R9 270's arrival in November 2013. Though the card's frequencies are substantially lower than the R7 260X's, use of a better architecture (Pitcairn Pro) enables the R7 265 to run over 20 per cent faster.