QUOTE(sharkz07 @ Aug 26 2014, 09:56 AM)
can you explain more i dont understand
btw just bought my zen6 16gb last night at direct coz 32gb is out of stock

ASUS's management of internal and external SD is very basic, like those you get on Froyo/Gingerbread devices.
What happens is that you have a primary and slave, just like how it was in Linux PCs. (after all Android is a version of Linux)
If you look into other cases, such as Samsung, they have managed to make the internal and external storage combined as one, not separate as 2 drives, or in some cases, "exchange-able". Which means,
if I install anything in ASUS, I have to prioritize between what apps can be switched to ext.SD, and what has to remain in internal SD. (apps like FaceBook, WhatsApp, needs to be installed in internal SD only, or else will have issues [so they insist]). In this practice, my phone for example, is still 8GB & 32GB storage.
But if I install it in a Samsung, semua jalan. That's because the phone recognizes the storage as part of the storage, and therefore it doesn't bother to really make distinction. Therefore in theory your phone isn't a 8 + 32 / 8 & 32 GB anymore, its a whole 40GB (because that's how it reads itself as it is)
There are ways that other phones have enabled "swap external SD as internal SD" which is great, but I don't see it happening with ASUS phones, and I don't think Class 10 XXX (forgot the code name) SD cards will cut it to be a proper storage.
I'm not sure since I haven't bought a Class 10 ultra fast card yet, (i do have one but its in my BlackBerry Z10, and for very good reasons why since that's my primary phone, as a phone, not as a consumption device) but the other class 10 cards (i would not know if its a imitation, I have no means to find out) just won't cut it, for example every time the phone boots up, I have to wait up to 2 minutes for the "greyed out" apps to load (because its installed in the External SD. Maybe a class 10 ultra fast card will help make it look like "normal", as in no "grey out icons", but I'm not sure.
On top of all of that above, consider the fact that currently ART's install size will be bigger than the current Dalvik we have. If you look at FB, it has 23mb apk, install size of I think 70++mb, and it will be bigger when its fully converted into ART, come 4.4.4 (kit kat), and the card's format has to even change to fully utilize the speed (but then again, bigger installation size!) and people like us who are stuck with an 8GB sized internal ROM, are... f***ed up real bad by ASUS.