Maximum (micro) SD card speed class for HTC EVO? What is the maximum class (e.g., 2,4,6,8,10) supported of microSD card supported by the HTC EVO?  

I noticed an improvement in performance when upgrading from the Class 2 to a faster card on my Hero.  I don't want to pay extra for performance that won't benefit my EVO.

HTC and Sprint have not included this information in their specs and I can't find it elsewhere.  Either I'm not understading something fundamental about SD classes or it's not published where I'm searching.
It looks like someone sent HTC an email back in July and got the following response:


  I understand you want to know which speed is the best for your device as far as SD card is concerned. We have tested the devices on a class 4 speed. I could not recommend anything higher than that. The phone may be capable of running a higher-class speed, but we have only tested it on a class 4.


You may also want to email HTC support and see what they officially say.  From I've been reading, people have been using Class 6 just fine.  Not sure about 8 or 10.