Can't give specifics but can imagine they'd run very well. The Mini i5 can run some newer games pretty decently (was playing some Portal 2 just earlier) so older games such as the older GTAs should work with very good framerates.
and note, the one on the Mini uses GDDR5 memory so it's a bit faster too. And all the games listed with high FPS on medium to high settings still have better graphics than the GTAs. I think even GTA IV should run fine on medium settings.