There is no easy answer because a lot depends on how you use 2020 Design. If you want to do a lot of Panoramic 360 renderings then the processor is the bottleneck (doing a panoramic render maxes out all the cores/threads on my i7 completely) but if you are only doing standard renderings then having a decent graphics card helps.
I’ve personally found the biggest difference in use to be linked to the processor speed – if you can overclock the existing i5 then do so but also upgrade the RAM to 8GB and put in a decent card such as the Nvidia GTX1050 (try and stay away from AMD COMPLETELY). A higher spec card than the 1050 only marginally improves rendering speed if at all.
However, you can buy a new computer for not much more than upgrading the old one so I would recommend upgrading the computer completely. The ideal scenario is an i7 or top end Xeon running at the fastest possible speed and coupled with a decent (don’t go overboard) graphics card such as the NVidia GTX1050. 8GB of RAM is a must and an SSD boot drive makes for a happy user.
