Test using a 640 by 480 window, bitmap & mask.

BltBitMapRastPort() took 565 uS

With a clear mask:
BltMaskBitMapRastPort() took 2868 uS (5 times slower than no mask)

With a set mask:
BltMaskBitMapRastPort() took 153361 uS (271 times slower than no mask)

With an alternating-line mask:
BltMaskBitMapRastPort() took 79492 uS (141 times slower than no mask)

With a chequered mask:
BltMaskBitMapRastPort() took 87351 uS (154 times slower than no mask)

With an alternating-thick-line mask:
BltMaskBitMapRastPort() took 79446 uS (140 times slower than no mask)


PowerMac MDD G4 @ 867MHz