Problems with 760a and marvell 6111 on msi neo2 fr

i can’t burn faster than 12x. if 12x is reached the buffer is underunning all the time (not the mainbuffer only the drive buffer). i tried differen cables and different settings (master/slave, single master) all didn’t work.

my 2nd burner (samsung 203) works fine (via sata connected to marvell).

is there anything i can do? (other firmware?)

thx in advance