but this games .dat in girigiri, it's necessary?

hi, I tried a lot of times playing radiant silvergun on girigiri and every time it crashes or freezes, actually I've played it for hundred hours but I never be able to see the end. (main crash after xiga..)
Then I try to erase the game data from games.dat and the results are that radiant seems to work perfecly and with less crashes.

but what's the purpose of games.dat? it's an optimization for low hardware pc's or the games running ok without it too?

thanks!!