Safari browser is running slowly
I have an iMac made in mid-2011 with High Sierra OS. My bank website advises me that my browser and or my OS is no longer compatible with their website software. I have had other websites also advise the same.
Is there a way for me to reload Safari that might correct some corruption in the software?
I have emptied the cache but that has not improved the speed of Safari.
Thank you
iMac 21.5″, macOS 10.13