Random Short Freezes

[Laenaya]

You can try playing with the commands "/mineffect" and "/aura" on, they should slightly help you about hardware lag. I personally play with both on, plus "/fog" off. Closing unnecessary programs/processes and keeping your HD not too full also helps, like Ptah already told you.

Now if your heRO window doesn't literally stop responding (like when your mouse pointer freezes and stuff) but you just can't move, it's most likely a connection issue. This can be bettered sometimes disabling the "Nagle Algorithm", but it's not something guaranteed.