The GY-HM170 supports a better memory card type than most camcorders of this age and spec. This camcorder supports an SDXC memory card, whereas most big sensor size video cameras that have been on the market for a comparable time to it support an SDHC memory card. 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 video cameras of a comparable type and age to the GY-HM170.
An SD memory card is the worst supported memory card type amongst comparable types of camcorder.
SDHC cards are DS cards with a higher capacity of up to 32GB.