Yesterday I inserted a SanDisk 64 GB Micro SDXC Class 10 memory card in my Asus 700T and a second one (in adapter) in the keyboard dock. Both were recognized and useful without any formatting necessary. I am upgraded to Jelly Bean OS.
For those of you considering buying a 64gb MicroSD card with your tablet, beware of the latest crop of class10 SanDisk cards, which apparently only work with ex-fat, cannot be formatted to NTSF and only to Fat32 with a third party utility. SanDisk also reports their class 10 64gb MicroSd cards are not compatible with Android 4.0 or above, a known issue.
I can confirm that Class 6, 64gb MicroSd cards, can be easily formatted in a Windows7 computer. They work without a glitch:
Amazon.com: SanDisk 64GB Mobile Ultra MicroSDXC Class 6 Memory Card with SD Adapter - Retail Packaging: Electronics
I can confirm that the following:
SanDisk Ultra 64 GB microSDXC Class 10 UHS-1 Memory Card 30MB/s with Adapter SDSDQUA-064G-U46A:
Amazon.com: SanDisk Ultra 64 GB microSDXC Class 10 UHS-1 Memory Card 30MB/s with Adapter SDSDQUA-064G-U46A: Computers & Accessories
The above card cannot be formatted in a Windows7 computer. It is impossible to format the card to NTSF. SanDisk recommends using the following utility: HPUSBDISK.EXE, free, google it. I downloaded from Softpedia and it's quite the task to find the actual download link amidst all of the adware. I was able to successfully format the card to Fat32 for a friend who wants it for a Sandisk mp3 player, of course not compatible with ex-fat.
The Sandisk tech support guy said that their class 10 cards are not compatible with Android 4.0 or above.
This would seemingly include the following:
SanDisk 64GB Mobile Ultra MicroSDXC Class 10 UHS-1 30MB/s Memory Card with SD Adapter (NEW VERSION) - Retail Packaging with Komputerbay SDXC USB Reader
Amazon.com: SanDisk 64GB Mobile Ultra MicroSDXC Class 10 UHS-1 30MB/s Memory Card with SD Adapter (NEW VERSION) - Retail Packaging with Komputerbay SDXC USB Reader: Computers & Accessories
I ordered two but am returning both, unopened, on the advice of SanDisk and KomputerBay
The Sandisk tech support' party line is that MicroSD cards are only for phones. I don't know what they're thinking: tablets, cameras, mp3 players, mass storage... I can't understand why they would design these cards to be incompatible: ex-fat or the highway.
I'm glad it's working for you on your TF700! Exfat only doesn't work for me so I'm sticking with class 6 cards. Here's how I converted the class 10 card and the root of its problems:
Sucessfully converting a Class 10 64gb MicroSd to NTFS or Fat32
Again, glad it's working for you.
32gb Transformer 101 & 201 with dock
Samsung Galaxy S3
eee 1215 netbook
Nexus 7 32gb
Microsoft is doing everything in their power from using these larger cards without you paying them $$$. SD cards (ANY KIND) are just block devices. They can be formatted to any file system the formatting device supports. Microsoft has disabled fat32 format in their own software to force the issue, and has paid SanDisk to add a partition to so you can't mounting it normally, but you can always use non-Microsoft software to get around this. Follow thenrik's link, and there is a easy to use Windows program that will format any 2TB or smaller SD card (again and kind of SD flash card), to fat32 or NTFS. The only limit on fat32 is file size must be less than 4GB. (no Blu-Ray! ;-) ) Now if you want Linux formats, you'll need a different tool, I know there is one a windows one, but don't have a link.
BTW, I bought one of these new Class 10 cards, and after using MiniTool, my TF201 still would not read it. I put it in my Bionic, and it worked fine, and the "old" Class 6 (???) that was in my bionic works fine in my TF201.
I think ASUS needs to look at their microSD card code a bit, as something seems just a bit flaky there. (I also swapped them back after the "new card worked in my Bionic, and still no joy)
The class 10 would flash an icon that it was mounting the card, then nothing.
BTW, what happened to the "format SD" command that use to be there? My Bionic doesn't have it anymore, either.