This may be just coincidence, but I tried increasing the swap file size in Windows 10, and I ran several quick races without seeing the stutter. I'd like someone else to test that to see if it has any palliative effect. I started out the evening with the swapfile at 4G and got stuttering on the second lap of a quick race at Bahrain. I then changed swap to a minimum of 6G (with a max of 9G), rebooted and ran several five lappers. On none of them did I see any stuttering. The swap (aka Pagefile) can be found at Control Panel | System | Advanced system settings | Advanced | Performance Settings | Advanced | Virtual Memory Change | Custom Size. Set some Initial and Maximum size and Ok out. I used Initial at 6G and Max at 9G. My totally unfounded theory has to do with F1 writing the replay file. I think it chunks everything into RAM/swap and then has to do a disk write and that's what's bogging it down. I know, writing to swap should be the same as writing to disk since they are the same operation. As I said, it's an unfounded theory. Just to be sure everyone understands, I made these changes AFTER today's (8/30/16) patch was applied. I saw the stutter after the patch.
UPDATE. Well, I didn't get any stutters in any of the quick races I ran. Then I went into practice from the quick race menu and got the stuttering back. But it only happened once a session instead of every few laps. So I don't know. But I guess that was obvious, wasn't it?