Even if the camera doesn't specifically support UHS-I, it'll still make a difference. Here's a review for the SanDisk Extreme Pro 95MB/s SDXC 64GB card on B&H:
5GB Blackmagic file R/W test (limited by my Clevo laptop's card reader) 76MB/s read, 72MB/s write.
In my 60D:
Previous Sandisk card has 45MB/s read, 41MB/s write. This allowed a burst of 8x continuous shots @ 5.3 shots per second, then 1 shot per second thereafter capturing RAW+JPG each shot, ie 33MB per shot. (will also allow 50x shots continuous JPG only).
But, this new 90MB/s Write card has transformed my 18Mpix CANON 60D camera. Allows 8x RAW+JPG shot initial burst, then a just perceivable pause (eg 0.25sec), then another 6x RAW+JPG shot burst before slowing down. Effectively 14x RAW+JPG shot continuous bust now = 460MB captured to the camera's buffer just in 3.5 seconds ! This is a huge improvement. And the camera is ready for another shorter burst after another second pause. I had found the 8x shot burst limiting for kids sports.
18Mpix RAW only – now is 15x shot continuous burst (no pause) before slowing down.
VIDEO: The change here is the recovery time when banging of still shots during video. The cycle time is much shorter and little of the video is lost now (was typically 1sec of video lost – intrusive for sports).
From 8x shot burst (also CANON's specs) to 15x shot burst."
I have personally confirmed this fact when using my 60D with the card aforementioned in the review. On a slightly different note, I also have a Lexar Professional line SDXC card (LSD64GCRBNA133), and even though it's guaranteed to have a min. write speed of 20MB/s, my 60D stutters like crazy while recording video and randomly stops while recording. The number of RAWs it can burst is also quite inferior. I also have a Transcend photo SDHC card, and it too can't hold a candle to SanDisk (and they were all expensive cards, none of them were $30 cards from Walmart). From personal experience, the IMCs used in the Sandisk cards are most certainly better than IMCs used by other brands.