You’ve not said what release, I believe it’s 22.04 as per this question but it’s best if you’re specific.
I’ve already stated being specific with details matter, as 22.04 media is available that used the 5.15 GA kernel stack (ie. older which can perform better on older devices) and HWE which currently is using the 6.2 kernel, which will perform better on newer hardware.
The mention of windows 7 implies to me older hardware, but I don’t know your device. You also mention RAM is moer than 3GB but not saying what it is; in recent years anything less than 6GB is considered minimal RAM for web browsing, thus using sufficient swap is pretty essential which is what i’ve already alluded to.
You can use uname -r to get details of what kernel you’re using; on my system that responds “6.5.0-10-generic” where the only detail I’m interested in is the first two numbers, ie. 6.5 being my current kernel. For Ubuntu 22.04 LTS the numbers should be 5.15 if using the GA kernel stack, or 6.2 if using the newer HWE kernel stack (your install media will determine what yours is).
Unless you’re using propriety (closed-source) kernel modules you can have both GA & HWE installed, selecting which you use at boot (at grub), though it’ll use slightly more disk space if you keep both installed, plus both will get updated meaning slightly more bandwidth used during upgrades… but that is one option.
An alternative that is even easier is to not install anything, but boot live media using different kernel stack, and just using the try mode provided with Ubuntu media; see if it makes a different. Ubuntu 22.04 LTS media is available with the 5.15 (22.04 & 22.04.1) , 5.19 (22.04.2) & 6.2 (22.04.3) kernels currently.
If it’s mouse settings; configuration settings for Lubuntu can be found in the manual on the page Chapter 3.2.8 Keyboard and Mouse — Lubuntu Manual 22.04 documentation in a manual page I’ve already provided; but as already stated I’d try increasing swap first if your RAM is less than 6GB, with details in this link already provided.
As I don’t know your hardware, I don’t know which approach is best; I can only give my 2c (being what I’d consider).
- try other kernel stacks via live media and see if it makes a difference; this doesn’t require any change to your system thus has no negative consequences; except it requires multiple ISO downloads/writes to media & testing via USB-thumb-drive media; ie. time being the cost. I’m offering this as it’s easy to do (I consider it easy anyway), as drivers are kernel modules, thus changing kernel stack causes modules (aka drivers) to change, however if you’re missing a synaptics or other driver this won’t help, as I’ve never used hardware that benefits from those modules
- try different stacks on your machine; may make no difference though (esp. if your issue is a missing synaptics module), but this is often very helpful on older hardware (when using the HWE kernel stack) or newer hardware (and using GA or older stack)
- if your swap is 512MB only; that is where I’d go first (
free -h), by increasing it… An example I’ve written about a number of times was my stealing half (4GB of 8GB) from a box so I could test another box with some RAM, not expecting to notice any difference (on box which lost half its RAM) — boy was I wrong; a 8GB system was great to use, but with only 4GB the box was annoying until I increased swap from the defaults - checking settings as per manual page I provided; it may or may not help
ps: If I use/say Ubuntu rather than Lubuntu; read it as Lubuntu if you’d prefer; I’m using Lubuntu/LXQt currently, but I do see my system as a Ubuntu system; I’m using Lubuntu/LXQt as GNOME (Ubuntu’s Desktop) just isn’t my cup-of-tea, but I do like the Ubuntu base all flavors of Ubuntu use.