So I've been preparing for ES:O by playing MMO's, WoW, Lotro, Star Trek Online, SWTOR. What I don't get is, games like Deus Ex HR, Oblivion, TF2, Minecraft, and other low end games run fine on my PC. WoW and Star Trek Online work fine, but Lotro and Swtor lag like crazy, my internet connection runs HD youtube vids, and online games all the time. Why is this?

System specs:
CPU: AMD Athlon 64 X2 Dual Core Processor 4200+ 2.20GHz
GPU: Nvidia GeForce 8400 GS
RAM: 1GB

Your small amount of RAM probably play a large part of it. 1GB doesn't really get you far these days, and Windows probably take up a large chunk of it for itself, so there isn't much left to use for the games.

The CPU is another factor, I believe. Guild Wars 2 for example is playable on most GPUs but it is VERY CPU hungry.

Depends on the optimization of those games, I guess (Since you mentioned you play WoW and Star Trek Online fine).

I haven't played too many MMO's, but I have played Lord of the Rings Online for a while.

It is pretty demanding on the graphics side, and that GPU is really not very powerful.

And as Freddo has said, 1GB of RAM is pretty low.

WoW was designed (atleast originally) to support almost any hardware configuration, so it's not too much of a surprise that it runs decently on that system.

The 8400GS is a very weak card, and as TOR is one of, if not the most demanding MMO on the market, that would explain the performance issues there. I'm not sure about the requirements for LOTRO and STO, but WoW is not demanding at all so you shouldn't have issues with it.

Yeah I know it's not much of a computer, but the graphics on those games just svcks so bad, I can't imagine they'd be that hard to run! I've given up on a gaming PC I just want to be able to RUN games. Thanks.