Hello Rupert,
Thank you for your contact
This effect is done because of the shared RAM memory. 8GB of RAM is being automatically distributed over the CPU and the graphics card.
Only if the information about 8GB of RAM is visible in the system - that's good - an indication that the newly installed RAM module is visible and working.
Windows handles the RAM memory distribution automatically and uses the "unavailable" memory to boost your graphical performance.
Best regards,
Fujitsu Support Forum