Solved: OS4 + Pegasos II + sil3112 problem

So, recently I've bought a nice cheap 500GB sata drive for my peg2. After looking what hardware OS4 and Morphos supports I ordered a sii 3112 based, 2-port sata pci controller to get my new HD running. And it works. The problem is that while under MOS I get a great 90mb/sec raw read, under OS4 I get a low 4mb/sec which is frankly less than 6,5mb/s my fastata on my A1200 does! And it's not like I rely just on a benchmark, it IS that slow in copying files and even reading big dirs - it's like I'm on a classic miggy all of a sudden! Also there are stutters when that particular drive is working hard, ie the mouse movement is not smooth, mp3 playing pauses regulary etc. What I'm thinking is that for some reason OS4 is reading the drive in PIO mode, but is that even possible for SATA??? I think not. But if that's the case, is there ANYTHING I can try to make it work at its proper speed? The hardware is fine as it works as intended under MOS.

Any ideas anyone here? Thx!

@Vulture

Of course it is reading the drive in PIO mode - this is the (secure) default behaviour, you could check this with c:idetool. You can turn on DMA modes by setting the right variables in nvram.txt - see IDE documentation.

@cha05e90

thx for the suggestion, I'll try it as soon as I get home and see what happens (fingers crossed)!

edit:

did it, it worked fine, many thx man! :)