4 seagate hdd, which disk should have the OS?

[ranjan2001]

NEED URGENT REPLY
I am about to format my system,
I have 4 seagate hdd having different specs ranging 2mb buffer to 32mb buffer.

Detailed spec can be checked here *www.seagate.com/www/en-us/

ST3160211AS-160gb /2mb buffer (4yrs old)
ST3250624AS-250gb /16mb buffer (3yrs old)
ST3320620SV-320gb /16mb buffer (1.5 yrs old) this hdd has faster read/write
ST31500341AS-1.5TB /32mb buffer 120 MB/s sustained data rate


Should I load the OS on the latest HDD having 32mb buffer & use the 16mb & 2mb buffer hdd just for storage?

Need help in planning my dual boot XP/vista x64 system.

 

[ThinkFree]

Install OS on that disk which has fastest read/write speed.

 

[prathamtawde]

ST3320620SV-320gb /16mb buffer (1.5 yrs old) this hdd has faster read/write

 

[ranjan2001]

That has to be the latest 1.5TB disk then, actually I have got that disk for data storage but if its required then I will create 3 40GB each partition on it & use the rest for storage.

ST3320620SV-320gb /16mb buffer (1.5 yrs old) this hdd has faster read/write

Where did you find that its faster than 120mb/s
On the seagate site the data transfer speed is not mentioned for ST3320620SV, but I do remember that this disk was specially made for video encoding which required faster read/write operations.
EDIT
I downloaded the spec sheet & in that its mentioned as 72mb/s sustained data transfer speed for the 320gb disk.
So the fastest is 1.5tb hdd with 32mb buffer.