FPS drops every 2 mins on csgo

Aug 9, 2018
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Hi so I have a laptop that isn’t very good but used to be able to run csgo on around 50-65 FPS all the time but I reinstalled it and started playing again yesterday and it was going good for around 5 mins and then the FPS just dropped to like 4-18fps for around a minute and a half. I’ve literally tried everything. Help would be appreciated. Thank you.