I've been having a lot of stutters in TF2 and thought that something was up. I tried playing on low for a while and felt no apprecitable difference. After getting fed up, I started watching computer usage with MSI Afterburner. I noticed that when my performance was normal I'd be sitting at around 60-70% cpu utilization. Once things got choppy my cpu was often at 100%.
I moved on to task manager, and it was quickly made clear what the issue was. Steam Client Webhelper had 25%+ CPU utilization. I've known for a while that opening up steamprofiles in the overlay would tank my performance, especially if they had any animations. However, this has begun to happen even without anything open in steam interface.
I've tried deleting web browser history in the steam settings and that hasn't seemed to help. The only solution I've found that helps is to kill the task in task manager but it's only a bandaid fix for about an hour.
Specs:
i5-4440 (quad core base clock 3.1 ghz)
NVidia 980-TI (slightly underclocked)
24 gbs am (1600 mhz ddr3)
Windows 10
Game on an SSD and windows on a separate SSD