See if you RAM MEMORY is listed for the 2nd Generation Processors under your motherboard's QVL List: Support For B350 KRAIT GAMING | Motherboard - The world leader in motherboard design | MSI Global
RAM MEMORY may be compatible with the 1st generation Processors but not with the 2nd Generation Processors.
If the new AMD processor was incompatible with the Motherboard, It wouldn't even boot up.
Also update the BIOS/UEFI and CHIP Set versions to see if it makes any difference.
also check Task Manager and see if you have a program that might be causing the delay while surfing by keeping the Hard drive busy all the time.