Lagging how? There isn't much know with just that. System specs? When is it lagging? How?
This is just a very run-off-the-mill RPGM game, so either you're running it on a potato or you have some issue with your setup for it to lag. In the first case we can't help and in the second we need a lot more details to even begin. I'd try checking dependencies and locale to start with as the general advice that tends to work pretty often.
For the record, I haven't seen an ounce of lag in this one.