You definitely have the specs for ps2 emulation.
What id suggest is making sure your drivers are all up to date (especially your video card), and also all your windows updates are up to date.
You could try getting a newer or different version of pcsx2 http://pcsx2.net/download/development/svn.html
What graphic settings are you using? try changing it to the default values, and try changing between dx9 and dx11, and also try hardware and software for both. See if any fixes the problem you are having. As its quite common for one backend or rendering option will cause problems and other work. Like it could very likely be that that game doesnt do well with hardware rendering.
Dont bump up the internal resolution until you have fixed your problem. also it will very for different games at what you can put it at, before slow downs.
If using software rendering, set rendering threads to 1 or 2.
Under emulation settings > speed hacks. leave these at the default setting. Moving the sliders to the right give speed ups in emulation, but can cause major audio and graphical glitches. So always leave them to the far left unless you need the speed, and then just move it 1 spot at a time.
Since your cpu has 4 threads, you can enable MTVU for a moderate speed up, as its able to take advantage of the extra cpu threads for better performance. (a few games may have problems with that, but i think most are fine)
if after all this nothing solves your problem, maybe try going to the pcsx2 forum, as you may get more specialized help on your problem(s).
http://forums.pcsx2.net/