Firefox bug?

I was working on my presentation when I realised the PC was loading a lot slower than usual. I thought it was some virus attack,but I didn’t download any risky files lately as in .exe and etc. It was so slow that even mp3 player on my pc was stuttering,as if the singers are choking in water while singing.The best COA next is to bring up the Ctr + Al + Del Task Manager.Then I saw something very unusual.No wonder my pc is so slow

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WTH?175k mem usage?No wonder my pc slowed down.Apparently as my friend told me it is a bug in the widely used browser.Maybe someone can enlighten me on this.