I think your system specs refer to some other computer right? As for slow boot, its possible you have a large no. of programs autostarting at boot. Click on Start orb, type msconfig, hit Enter. Click on Startup tab and uncheck stuff you can manage without, reboot. As an indicator, my computer boots only with the antivirus, touchpad manager and password manager checked.
You can run the app called Soluto, it'll tell you whats hogging boot times in a simple, graphical way. www.soluto.com
As for video lagging, it could be due to low video ram. If its adjustable, try cranking it up. Its not clear how much total RAM you have, max it out for the best bang for the buck. Also, try cutting down on fancy visual stuff, that'll free up more RAM. Again if you're working on a lot of memory hogging apps simultaneously, it could create problems.
Also try updating the video drivers
If you're seeing a lot of hard disk thrashing, it could be due to indexing. Click on Start orb, type services.msc, locate "Windows search" and stop it plus disable its startup. Also run defrag, run a malware cleaner (like malwarebytes antimalware) and empty out temp files with CCleaner.