Lagging in the game

Hello, I'm sorry this had to be there at least milion times, but I'm truly desperate. I bought ThinkPad E590 i7, 8th Gen, RX 550 2GB 16GB RAM. I dont know where is a problem, but when I start any game after couple of minutes it start lagging as hell. Even games like Dota 2 or Skyrim sometimes...

Hello, I have recently bought an ASUS laptopn- model X555DG AMD FX-8800P Raedon R7, 12 Compute Cores 4C+8G 2.1GHz 8Gb RAM AMD Radeon™ R7 Graphics + Radeon™ R8 M350DX Dual Graphics with 2GB DDR3 VRAM Built-in FX-8800P I tried to play GTAV and Batman on the laptop, but the game is lagging...