It is just a fancy pants name as far as i can work out... most likely just a turd upgraded controller thats all... compatible device, as in a lot of cases refer to idiots who try to stick a square object into a round hole and then sue them for it not working.
i got samsung class 10, does 12mb/s write 17mb/s read, works a charm on psp with a rip-off adapter, though i will get a genuine photofast somewhere down the road. just on psp it gives me 7mb/s write... read stays at 16mb/s... from what i read photofast adapter is capable of speeds above class 10, as even my rubbish rip-off adapter can pull off 16mb/s read speeds...
it will work fine, though probably at normal speeds...
UHS Speed Class
The Ultra-High Speed (UHS) interface is available on some SDHC and SDXC cards.[41] The following ultra-high speeds are specified:
UHS-I cards, specified in SD Version 3.01,[37] support a clock frequency of 100 MHz (a quadrupling of the original Default Speed), which in four-bit transfer mode could transfer 50 MB/s. UHS-I cards declared as UHS104 also support a clock frequency of 208 MHz, which could transfer 104 MB/s. UHS-I is the only class for which products are currently available.[39]
Double data rate operation at 50 MHz (DDR50) is also specified in Version 3.01, and is mandatory for microSDHC and microSDXC cards labeled as UHS-I. In this mode, four bits are transferred when the clock signal rises and another four bits when it falls, transferring an entire byte on each full clock cycle.
UHS-II cards, to be defined in Version 4.0, further raise the data transfer rate to a theoretical maximum of 312 MB/s.[42][43]
UHS memory cards work best with UHS host devices. The combination lets the user record HD resolution videos to tapeless camcorders while performing other functions. It is also suitable for real-time broadcasts and capturing large HD videos.
Cards that comply with UHS show UHS-I or UHS-II on the label, and report this capability to the host device. Use of UHS requires that the host device command the card to drop from 3.3-volt to 1.8-volt operation and select the 4-bit transfer mode.
now i cannot find which version of SD cr5400 supports, but i assume it is 2.0, in which case it should work at normal class10 speeds, though again, i got no idea... it does say it support speeds of 10mb/s which implies it would support UHS... shoot them an email or something and ask...
the cards will work quickly anyways and at that price can you really complain...