some games slow down with triple buffer on

[Josef1975]

on my cab I'm using a P4 2,5hgz (socket 478), 1gb ram ddr400 and vga radeon 9250+soft15khz. using mameuifx 0.155 (but also with older versions) if I turn on triple buffer option on some games (expecially vertical shooter like raiden) music slow down during game. no problem with other games like GNG, Golden Axe etc.. of course without triple buffer I get on video some tearing effects during game, enabling it the audio is slow than normal (non really distorted but the song go slower... the fx effects seems to be ok).
I'm using directdraw (not direct3d because of I'm using an original arcade monitor), no hw stretch an all games have custom res (made with avres)
any ideas?

[SailorSat]

Are you running the vertical games in horizontal mode? If so, that is normal, as the higher resolutions has a lower refresh rate.

[Josef1975]

yes! having an horizontal cab  ( http://digilander.libero.it/venturi1975/cabinet2/ladercab1.jpg ) I run vertical games in that way.
so I simply have to disable triple buffer for vertical shooter an keep it enabled for native horizontal games?
thanks for the reply.. and for soft15hkz!!!