I've found that with Windows 10, Firefox + Youtube have dropped frames at 1080p60. It doesn't happen with Win7. This is VP9 video so it's entirely CPU decoded. CPU load is only like 20%. On a hunch, I installed LatencyMon to see what DPC Latency was looking like and yeah with Youtube playing a video in Win10, there are huge 2000-6000us spikes in DPC latencies. It doesn't happen in Win7. I'm not sure if anyone else has noticed this. Win10 seems to behave well otherwise, but now I'm suspicious of that and wonder if for example games stutter more there. I noticed a lot of people had NIC driver BSODs back when 10 was new but that doesn't happen anymore.