The home NAS device launched by Gigabyte, and its inability to support HDDs of over 3 TB, shows that 4 TB models have yet to become a full part of the storage industry.
This is why it might come as a surprise to learn that drives with 5 TB capacities are already being prepared.
Western Digital itself has revealed this, albeit indirectly.
Leaked information from AlwaysMoreDigital and Hardware.info shows a 5 TB WD Red (model: WD50ERFX) and 5 TB WD Green (WD50EZRX) that will be released in the fourth quarter of 2013, after October most likely.
Prior to that timeframe, some 4 TB units will join the Red and Green series as well.
All units will have 64 MB of cache memory and support for SATA 6.0 Gbps transfer speeds (SATA III).