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

Yes , this board can support Intel Pentium G620(65W) CPU. Please refer to below CPU suport table for reference.



- CPU support table