Does Wotlk with LOD models affect pc performance?

As it says in the title... does WoD models in WotLK affect my pc performance?
I don't know if this question was asked before, but i can't find anything about it.

What are LOD models?

If you're talking about WoD Models then yes it is more graphics intensive.

Yes, I am sorry... I mean WoD models. So if my pc isn't that great, I should get the old version of WotLK?

Ideally yes.