Nvidia has beaten AMD to the punch with a full WHQL certified Windows 10 GPU driver, version 352.84, supporting their last three generations of desktop and four generations of mobile GPUs. This is a fairly major milestone for previewing Windows 10 on modern desktops, as solid video driver support is key to a good experience, and video driver issues have been known to plague Windows Insiders before. If you have one of the supported GPUs on the list in your system, and you are running Windows 10 Technical Preview, you should head either here for the 64bit version or here for the 32bit version depending on your architecture. This should improve your Windows 10 experience, although without a proper changelog it is hard to say what, if anything, has actually been fixed.