The HDR-CX900 supports an SDXC memory card which is better than the SDHC memory card supported by most video cameras of this type and age. This video camera also support MS PRO Duo, MS Pro-HG Duo and MS XC-HG Duo and SD memory cards. SDXC cards are SD cards but with a much higher capacity and faster processing speeds. They have a maximum capacity of 2TB (Terabytes).
An SDXC memory card is in fact the best supported memory card type across all camcorders of this age and spec.
The worst supported memory card type across similar types of camcorder is MicroSD (Transflash).
SDHC cards are DS cards with a higher capacity of up to 32GB.