The 9500 has 4 pixel pipelines enabled on the core, but there are actually 8 on the core, 4 are just disabled. A softmod on the card means that the extra 4 pixel pipelines get enabled on the core when you flash the BIOS of the card via software, or some other software thing.
There is another way to enable to extra 4 pipelines on this card, by resoldering a resistor on the card. This is not a softmod, as its done without the use of software.
The chances of purchasing a card that you can do this to are very slim though. (Radeon 9500 non-pro with an L-shaped layout of the memory chips I believe)