Unit placement lag

I have a really good computer. Below are specs:
2.5ghz P4 Processor
512mb RAM
160gb Hard-drive
52x DVD
52x CD-RW/R
512mb graphics card

I can run Warcraft 3 with best graphics options and highest resolution fine. My problem is, when I try to place a unit in WE, the tranlucent unit model attached to the mouse moves very slowly and clumsily. It makes it hell to place units. I tried running WE with lowest graphics options and it still happens. I also removed the Unit List (the list underneath the model preview window, and I closed every other non-essential program, but still I get lag.

Please could someone help me. If you want more details, then just say so and I'll give them.

Sounds kinda bad. Do you have 50 other programs running when you make maps? :bgrun:

That actually started happening to me recently too. The only thing I can link up with it is turning off brush swatches. (I think that is what it is called). Also if you put a start locationg so it clips with another unit it will drastically slow the WE down for some reason.