N2U400-A v1.x maximum CPU and HDD supported information as below,
HDD:400G
CPU: AMD Duron 200Mhz FSB CPU - 950 AMD Duron 266Mhz FSB CPU - 1800
          AMD Morgan 200Mhz FSB CPU - 1.4G
          AMD Athlon 200Mhz FSB CPU - 1.4G AMD Athlon 266Mhz FSB CPU - 1.4G
          AMD Palomino 266Mhz FSB CPU - 2100+
          AMD Athlon XP (0.18u) 266Mhz FSB CPU - 2100+ AMD Athlon XP (0.13u) 266Mhz FSB CPU - 2600+ 
          AMD Athlon XP (0.13u) 333Mhz FSB CPU - 3000+ AMD Athlon XP (0.13u) 400Mhz FSB CPU - 3200+
          AMD Sempron 333Mhz FSB CPU - 2800+