I'm using Vista and playback every video format under the sun including HD-DVD and Blue-Ray and it is solid for everything. No issues.
Streaming Devices: Nvidia Shield TV, 2x Roku 3's, 1st and 2nd gen chromecast, Amazon Fire TV stick 2nd gen, Apple TV 4, xbox 360, xbox one
Displays: Vizio M602i-B3, LG OLED65B6, panasonic ax100u on a 145" S-I-L-V-E-R painted screen, 40" Samsung(don't recall model #)
Receivers: Denon X3300, Yamaha RX-V663. Bluray/UHD player: Oppo UDP-203
Retired - HTPC: Intel e6300 2.8ghz, Intel DG45ID, 2gb DDR2, Radeon 5570, MCE IR receiver