I am evaluating the online version of ST8, which works fine along side my already installed V20, but the performance is slow. Can I install ST8 trial, and still keep using V20?
If you are trying to install the free trial, I presume you are out of maintenance on V20 and do not have access to ST8 product from the GTAC site. With regular installs, you will find instructions in the readme file to perform a multi-version install. The simplest might be to install ST8 trial on another machine.