The reason I have not gone up to SP3 is because the last time I tried going up to SP3, something went really wrong and I wasn't able to boot to windows. It was a never ending boot loop. I had to start all over again from scratch. I said at that point, I'll stay at SP2 until I upgrade to windows Vista or now windows 7.
The game should play fine on my system. So yes it's really frustration. I've checked all over the web and a lot in the Mass Effects community and there are many with the same issues. No resolve. It seems the devs are no help either. They are always pointing fingers at the end user.
The reason I decided to pick up Mass Effects was because I'm getting excited to get Dragon Age Origins. A new game from Bioware/EA. But, after this little experience, I might be having second thoughts about spending $50+ USD on something that could potentially not run when it's supposed to.
Just for giggles, I ran that website, "Will my system play it". And the results passed across the board for Mass Effects as well as Crysis, Far Cry 2, etc.. etc....