Why is My Roblox Studio Place Randomly Lagging?

Has anyone had an issue with one of their places starting to lag just randomly. My Roblox place I'm building has 9000 parts, It just spiked an hour ago and started lagging heavily. I'm not sure what could of triggered it, but I even restored to a previous version and the previous version was lagging. When I click the play button it seems fine and all the lag goes away. My other studio games seem to be working fine. I should also mention I've tried reinstalling Studio and clearing the cache. My PC is also fairly new with some higher end specs.

Is there anything I can do about this, such as seeing where the lag is coming from?

Well if it kept lagging during playtesting I would've checked out performance stats but sadly that won't show anything here.

I'd try checking out task manager for any high usage, let me know if either CPU/Memory or GPU goes up high and I'll look further

also this isn't really script help