I have answered this very question 3 times already today.
The MSI Twin Frozr 560's (and 570's) are factory overclocked cards (880Mhz on the 560's) sporting an improved cooler over the standard reference designs. What they do not have is the beefier VRM's on the PCB that other brands are offering. See this thread about fried 570's because of this issue:
The 560 Ti's have not suffered the sme fate due to damage as the 570's in the above reference.... However, due to the stock VRM's, you will generally be more limited on the amount of OC you can do on the card. The Frozr cards have a 6 phase VRM design as opposed to their Hawk and Lightning series which have higher OC's because of their beefier VRM's.
You might look at the Asus TOP model 560 To which is $5 more ... it has a 7 phase VRM, and comes factory OC'd to 900Mhz ..... and it's capable of going quite a bit higher (30+% over the reference speed)