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There are possible problems with SLI and CF
http://forums.nvidia.com/index.php?showforum=207
But don't let that put you off as that does not mean that you will be one of the unlucky ones.
A lot of issues regard heat, so simply having good airflow could help a fair few of those problems.
I'm not going into specifics at all the fact is they both have possible issues and the same could be said for CF.
Out of curiosity, what sort of issues?
Off the top of my head, microstutter is the only one that comes to mind.
Out of curiosity, what sort of issues?
Off the top of my head, microstutter is the only one that comes to mind.
If that's all you know of then you must have been looking at different NV forums to me.

I Don't go on Nvidia forums
But what sort of problems are the main ones?
And even then its minimal...
Microstutter will be minimal on your [email protected] if there is any at all, but on a PII 1090T if it's@stock???
You would be looking at pushing the 1090T as fast as possible to minimise microstutter on 570sli.
SLI/CrossFire can be trouble free, but it can also be a huge pita to some.
There are some folks here that think to jump in blindly when they aren't confident enough with 1 gpu never mind 2, which then turns into 'it's garbage/rubbish/too much hassle',(***delete as appropriate***) which leaves dual gpu's with a tarnished image most of the time.
I realise dual gpu's are anything but install and forget, but I don't believe they are as bad as some make out either, you should do your homework first and match up the right components.