SATA III HDD On SATA II Motherboard

[yullbarez]

Hi i must get new hdd cuz my own hdd is dead. I'll buy WD Purple 2TB it running 140 MB/s read speed. I thought it would run at 70 MB/s read and write speed avarage on SATA II. if it would run at half speed it will be slower than my old hdd. Could it run 140 MB/s?
if it requied my PC Specs:
CPU: Intel Xeon X5450 3.44 GHz OC
Mobo: Asus ROG Commando P965 Chipset
GPU: AMD FirePro V5800 1 GB GDDR5 128 Bit
RAM: Kingston 8GB DDR2(4X2GB) 800MHz CL6 RAM
HDD: Samsung HD250HJ 250 GB (Dead)
PSU: SilverStone 500W 80+ Bronze

Sorry for my poor english.

 

[jojesa]

A SATA III disk will not run slower than a SATA II disk connected to a SATA II interface.

Where did you see that WD Purple 2TB could run at 140 MB/s?
That 5400RPM drive average speed is around 97 MB/s.

May I ask, why are you looking at a surveillance disk, instead of a desktop disk?
A surveillance disk may spin 24/7 on your system and it could have an early end.

 

[yullbarez]

İ've found it cheaper than other ones in my country. I know it's a surveillance hdd. I didn't know it would be spin 24/7.