Dell Inspiron 5448 Core i5 5200u 8GB Ram, 250GB SSD, laptop graphics performance under Windows 10 is about half what it used to be on Windows 8.1. I haven't tried many titles but the only few ones were clearly lacking in performance, so much the integrated Intel HD Graphics would often perform better.
Games such as Skyrim, Fallout New Vegas, Plants vs Zombies Garden Warfare, The Secret World, Dragon Age: Inquisition would run below 20 FPS mark under Windows 10 using both Dell's outdated driver and the latest AMD Crimson software. The R7 m265 was in use all the time during the tests, I could confirm the % usage through MSI Afterburner, Intel HD Graphics would sit idle during the gaming seassion while the dedicated R7 would stay around 100% all the time, hitting 70ºc easily but wouldn't get past it.
Same games, same machine and depending on the game I can squeeze 40~60 average FPS on Windows 8.1 with drivers provided from Dell with it's own OEM profile, haven't tried to update them outside it.
So what's holding me back from upgrading to Windows 10 has been the graphics card, even the Intel HD 5500 graphics does perform better, especially in the older games. Can't to my little gaming on Windows 10, I first noticed it because it clearly affected the gameplay. So restored the computer with the factory settings, also did a clean Windows 10 install for testing purposes.
Tried to install the Windows 8.1 drivers on Windows 10 but it wont let me, gives all sort of errors.