This benchmark test,between Win8.1 vs Win10, might clear up some questions that members have.

Quote:

So I have just installed Windows 10, well upgraded the system from Windows 8.1. I figured the lot of you would like to see if there are perf improvements for graphics cards going towards Windows 10.

Now this is merely a quick news-item, but I have ran some quick benchmarks for you guys to compare a little to understand if at you may expect your graphics performance to improve. All test have been run on our primary graphics card test setup. This is based on a Core i7 5960X (8-core) X99 (MSI XPower) based PC with 16 GB of 2133 MHz (G.Skill) quad channel memory. This system has been overclocked toward 4.4 GHz on all eight cores.

The overall upgrade process was smooth, aside from a gfx driver crash this system has been running stable ever since the upgrade a few hours ago. Windows 10 does feel responsive and feels much bettter opposed to Windows 8.1.

The graphics card used was a GeForce GTX 980 Ti (reference running driver revision 353.62) to make sure we are not GPU limited. I am still running benchmarks and will add them as they come. The settings used are GPU stringent in terms of quality, they are the same settings per game or application as used in all our reviews.

Here are the initial results, the difference in graphics card performance in-between Windows 8.1 and Windows 10 is currently NIL. The one improvement we see is Battlefield Hardline, but I would bet money on it that this is due to a driver improvement. Obviously future games will support DirectX 12, that will make a big difference.

http://www.guru3d.com/news-story/windows-10-vga-graphics-card-performance-benchmarks.html