I bought a 2015 MacBook about a month ago. Macbook pro 2015 Core i7 16 ram 512 ssd I was very happy, as it is my first experience with a Mac system, especially since the device has very high specifications. Little did I know that I would spend all that time researching how to solve the slow and freeze issues in this system. 70 second startup 60 second after enter password 30 scond to open safari or another any app If i enable switch graphic Every thing lags mouse ,typing. I tried ==Instailed catalina same Problem. ==Update to big sur again same Problem ==Instail big sur from usb same Problem I make every thing ==Shift+ctrl+Optian+R ==Option+d +power ==Alt +ctr+p+r +power ==D+power ==Option+d+power ..... .... ... ==A+b+c ==X+y+z Safty mode,recovery mode,EarseF,First Aid After many attempts, I found the best solution is to install Windows on the device. The Windows system on the device works great I think I missed something in my attempt to enter the world of Mac. Sorry microsoft come back to you