As also @quququbebe & @unman did post, 40GB RAM in Thinkpad T480s is not a problem at all.
The Lenovo PSREF are outdated and we have found this to be the case with other ThinkPads before (Like the T450s the last one with DDR3 RAM).
I bought a ThinkPad T480s with Intel i5 8350U CPU. At first a crappy T490s was delivered, crappy because RAM isn’t upgradable in a T490s. Now finally the correct T480s was delivered and I installed the 32GB RAM module & QUBES OS 4.1.0-RC3.
Installation of QUBES OS was easy. It took <20 minutes. That’s a huge improvement of >40 minutes compared the ThinkPad T460s that sports 20GB RAM.
I have chosen the i5 8350 CPU (4 cores 8 lanes) on the ThinPad T480s platform very consciously. The heat development under load in the i7 8550U and the i7 8650U on Linux is on the high side. This i5 8350U CPU also scores better in various benchmarks than the two 8th generation i7 CPU’s I mentioned before do (the i7 8650U I know of my ThinkPad X1). This is despite the lower 6GB CPU cache compared to the 8GB CPU cache in the i7 CPUs
Installation of Qubes OS was simple and done in >20 minutes. That is a huge improvement of >40 minutes compared to the installation time needed on ThinkPad T460s. On that T460s i7 6600U (2 cores 4 lanes) with 20GB RAM installation of QUBES OS took me more than an hour.
As written earlier here I am new to Qubes OS and need to study this OS and learn. The hardware platform of the ThinkPad T480s seems very suitable, partly due to the RAM upgrade.
I posted this just FYI.
Hope it’s useful information to the forum members.