I dont have many parts in my game but it lags
1) It might just be you. A problem with your PC and the Roblox Client. 2) A free model virus. I suggest downloading Ro-Defender (https://web.roblox.com/library/1162148124/Ro-Defender-2-1-5) and using it to scan for viruses. 3) Too many raw parts. It doesn't matter if you have a small amount of parts, but if you have 20 parts in the game, and they all are baseplates or super large, then it can lag. Also I suggest using unions and binding parts based off matching material and colors.
Sincerely, Spiral