It`s been a while since last comparing the performance of the Windows and Linux Intel Haswell OpenGL graphics drivers. Last year when we looked at the Intel Haswell HD Graphics 4600 performance the driver speeds under Ubuntu Linux and Windows 8.1 were almost neck-and-neck, but since then it seems the rate of performance optimizations and improvements within the Intel Windows driver has outpaced the open-source Intel Linux graphics driver."
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips