iMax slow, I try PRAM reset, new sdd.

[matirials]

Hi, everyone and thanks in advance.
Please help me to figure out what is happening with my iMac, It is really slow, when starting up white screen for like 5-10 minutes, and then the os start up and the computer is back to normal. I try the PRAM reset, and I also put a new ssd but the slow remain. Any help ??. Also the Bluetooth key board stop working I have a usb keyboard now

 

[Just_Me_D]

Do you have a virus scanner running at startup?