Yes, this model with UEFI BIOS can support 3TB HDD. UEFI BIOS uses a GUID Partition Table (GPT) that can define hard drive larger than 2.2TB. As a bootable disk over 2.2TB partition, operation system like Windows 7 64-bit is required to support. For data only over 2.2TB, OS with GUID Partition Table (GPT) support is required.

Example, 
3TB HDD as data in GPT at Windows 7 :


System support UEFI BIOS GPT table:


3TB HDD as data in MBR at Windows 7 :



For more information about GPT&MBR partition, please refer to
http://www.uefi.org/learning_center/UEFI_MBR_Limits_v2.pdf
http://msdn.microsoft.com/en-us/windows/hardware/gg463525.aspx

This model can support EZ charger with gray color of front USB connector, F_USB1.



- For more information about EZ charger, 
http://www.ecs.com.tw/ECSWebSite/Support/Support_FAQ_Detail.aspx?MenuID=74&LanID=0&FAQID=94  
http://www.ecs.com.tw/extra/ezcharger/index.html
- User manual,
http://download.ecsusa.com/dlfileecs/manual/mb/H61H2-M3/H61H2-M3_MANUAL.pdf

This model may has concern on the S3 or S5 wake up by certain USB keyboard or mouse to the EZ Charger USB port. It means that you may have possibility not be able to wake up the system from S3 or S5 by the USB device. This is because the USB EZ Charger port provide 3 times current than general USB port for consumer products like iPhone, iPad and iPod touch that need large amount of current for faster recharging within less time. To avoid this kind of symptom, please attach the USB keyboard and mouse to the general USB port to obtain the expected behavior.



- More information for EZ Charger,
http://www.ecs.com.tw/extra/ezcharger/index.html

The model comes with 4 SATA ports, which supports SATA II 3Gb/s data transfer rate.