Attention all SIS lowers!

[Nowhere]

I've just realized that I still don't know to be honest what to buy.
Asus A7S333, MSI 746F Ultra or the new ASRock

Probably I'll just buy ASRock. I guess it should be ok, since they have some experience with the previous model. And it's the most future proof.

[DentyCracker]

If I didn't already have one, I'd get the new one even though it only has 5 pci slots

[Seaspray]

Personal experience

MSI 746 working absolutely fine here, running an older Palomino XP1800+ no problems. I don't run it 24/7 but it is on a lot running XP Pro, various games etc no problems.

One crash to date (~2 months of running) caused by Rise of nations. (Swap file too small, be warned this game needs a LOT of memory). Problem seems to have been solved by buying extra RAM (At least it has not recurred). Actually the system didn't hang but it failed to shut down requiring a press of the reset button.

As others have said, definitely consider an upgrade to your power supply if you possibly can. I ran my first Athlon system (KT133, TBird 1 GHz) on an older P2 power supply (235W). I didn't realise what was wrong at first, although the system ran fine most of the time I didn't realise what had been causing all the crashes until I replaced the PSU (previously blamed on windows, sorry M$!!).

As I understand SiS 748 has support for 200MHz fsb but is otherwise the same so I would go for that if you are intending to upgrade your CPU in the future to 200fsb (but remember there will be no more new Athlon XPs as Athlon 64 will be out soon).

Does Asrock = Asus? Although I have never used one. A7S333 is SiS 745 isn't it? If so that doesn't support 333fsb so limiting your upgrade options even more.