War based Free Roam?

Hello, ive been playing Oblivion and Fallout 3 for a while now. I LOVE the free roam and rpg elements, but I have a complaint. Their are some quest which have supposed "Large Battles" that consist of a max of 15 NPCs. Well this annoyed me, im really into the whole Epic Battle thing, and I was hoping for a huge skirmish of like 50 NPCs or even more. So, mr.smarty here (me) upgrades his computer, investing around 200-300 bucks, mainlly so I could, "Create", my own huge battles. So I moded Oblivion on my PC with a huge ass battle, got all exited then........... Im playing a slideshow. The lag was unbearable. Then I realized, after the 300$, that Oblivion's engine was not meant to support that many NPCs at once, so it was the game, not the computer. so what im asking is, Do you guys know of any War-based free roam games that have massive battles? Thanks for your time.

Thanks for the suggestion, love GTA, but still I onlly get like 10 peeps at max in it.

yeah, I would love to play WoW but unfortuneatlly am unwilling to pay 15$ a month. Sounds really fun though.

yeah I bought the game a while back, I didnt know how much it would cost, thanks for the suggestion, I guess ill reinstall, play private servers untill I get a ton of extra moeny then ill buy those card things and play on real servers. thanks again, cant wait to try this out. but with my luck something WILL go wrong.