None. You'll see a performance drop almost straight across the board.
The R7000/VE is an entry level office/multi-monitor graphics chip.
It's not much of a gaming solution at all, your looking at performance between that of the GF2 MX200 and GF2 MX400.
For a true performance upgrade you'd best look towards a Radeon 7500/GF2 Pro/Ti at minimum.
The R7000 is a damn nice card, with some solid capabilities at a great price point.... but it's extremely poor at best as a gaming board.