Hi Parrothead,
Dear member of SanDisk Community, welcome .
Friend:
1- Transfer speeds, do not depend the format.
2- In Fat32 (it’s an old format, compatible with many devices), the “limit of 4 GB” refers to the “size of a single file”.
3- For your Sandisk microSDXC of 128GB , is recommended the format, exFAT (is the more modern).
4- If you think, that the speed is slow, try the following:
4.1- Put the card in a laptop, directly to the port-card (not a USB card-reader).
4.2- Then, you can measure the speed with (app portable, free): USB CrystalDisk Mark, http://filecloud.io/9hqxp6fc
4.3- If still bad: in Start / My Computer, on the card icon, click the right mouse button, and then click in Properties/Tools/Error Checking and Repair.
4.4- If still bad: try formatting with (free): USB Flash SD Formatter, http://filecloud.io/jqtu1byc
5.0- If still bad, you can try with these apps portable (free), _ if it’s fake: _
- USB Flash H2testw, http://filecloud.io/jl4fhn9b -It’s the classic utility, but for 64 Gb, it takes ~ 4 hours.
- USB Flash FakeTest, http://filecloud.io/n074g3x5 -It’s similar, but has a quick option, and takes minutes.
5.1- To obtain the internal data of the UFD, you can use (apps portable, free):
- USB Flash ChipGenius, http://filecloud.io/rqa7etmv
- USB Flash DriveLetter, http://filecloud.io/vgqzcdyh
- USB Flash Deview, http://filecloud.io/srp2hegw
Luck, and then you tell us, what happened, please.
Regards, Alfred. (Google translated)