I have Dell Latitude E7250 laptop with integrated with CPU Intel HD 5500 GPU (CPU is Intel Core i5 5300U). When I had a single 8 GB memory stick, I had poor performance of Google Chrome and Firefox. Browsing of the web on Linux was laggy in comparison to Windows 10.

On this test on Google Chrome I had about 2900 points on Windows 10 and about 2000 points in Linux Mint XFCE and about 2400 points in Ubuntu or Kubuntu.
https://www.wirple.com/bmark/

I had also problem with watching 1080p60fps videos with Google Chrome and Firefox on Linux, my CPU usage was about 90% on Linux while on Windows 10 I watched 1080p60fps without problems. It is not related to lack of hardware decoding. On both Windows 10 and Linux I've tested this Youtube video with VP9 codec which is not supported by Intel HD 5500.
https://www.youtube.com/watch?v=1La4QzGeaaQ


When I added second RAM stick 8 GB and in effect my RAM started to work in dual channel mode, I got significant performance increasement. On Widnows 10 bmark result have raised from 2900 to about 3100-3300 but on Linux raised from 2000 to about 3100-3300. Furthermore, youtube 1080p60fps Youtube videos are played smoothy in both Firefox and Chrome on Linux. On Chrome I have cpu usage 40-60% per thread with above linked video.

It seems to me that Linux intel GPU drivers are significantly more sensitive to GPU memory bandwidth than Windows drivers. This problem was observed on every Linux distribution (different Linux kernel versions) and different desktop environments: XFCE, KDE, GNOME, MATE.

I've noticed that some people have similar problems with Intel HD GPUs on Linux.
https://forum.endeavouros.com/t/any-linux-distro-underperforms-with-intel-graphics-card-it-lags-when-using-web-browsers/3618

I've also reported this bug here.
https://gitlab.freedesktop.org/mesa/mesa/-/issues/6678