Leaderboard

Yes. But YMMV. Mostly, having the cache on a different drive means that you're separating out the I/O load, which can definitely improve performance. Though, this depends on the SSDs you're using. Things like AHCI vs NVMe, and the IOPS rating of the drive make more of a difference.

I'd take a wild stab and say probably negligible difference so long as windows is idle and behaving; checking task manager, my fileserver's boot SSD is currently averaging ~1% active time, ~450 KB/s transfer rate, ~1ms response time and <0.01 queue length over 60 seconds at idle, and it's a rather old SATA SSD. I think you're much more likely to run into other bottlenecks first. But YMMV as it depends how many simultaneous streams are you planning for, what other background programs you have running, etc. You could test it? Open task manager / resource monitor, set to show the drive's active time, transfer rate and queue length, then open some streams while you run an antivirus scan or create a restore point and so on?