Your processor and RAM are both about double mine and mine has no problem at all so that's likely not your problem. There are a couple issues that you might have however:
1) You might have a bunch of programs running that you don't know are running that you could really do without.
Here's a thread by fidel where he goes into detail about such things and others, but the one I'd look into first is the startup programs via msconfig.
2) You might have
features enabled in OOTP that are slowing it down that you could easily do without. Yes, that thread is more about simming multiple seasons, but it still very well might be of some use for you.
Also, I know you said you've tried with disabling AVG and you've had no noticeable difference, but you might want to still go ahead and set exceptions for the OOTP folders. AVG probably only scans everything infrequently, but when it does it could really bog down your computer.
I explain how to set exceptions for avast here in point #3, but the process for AVG should be similar (and if it isn't, googling should bring up a tutorial for you).