You are not likely to notice any difference between the H310 in non-RAID and the onboard SATA controller.  The H310 will likely unload some resources on the system, but you won't see any performance increase that might come from it.  The only really good reason to get an H310 (in non-RAID mode) is if you plan to use a single SAS drive(s) instead of SATA. Installation of the card is easy; installation of the OS isn't much different from using and onboard controller, except that you will likely need to load the RAID controller driver during installation.   To use the H310 in non-RAID mode, you simply leave it unconfigured (in the CTRL-R BIOS utility for the card).
I am about to buy T320 Server, having some question, It's just very small office use (2-3 user) ,  1. Is it OK if it has no Controller/Raid configuration?   I can save 128.97 (hot plugged - chassis) + 160.57 (H310 PERC)  = 289.54 $  2. If  I buy both items above (Chassis + H310) but  use only 1 HDD (config H310 PERC to No RAID), Does it has any differnces compared to NO Raid/No controller  3. For the installation , Can it be done by normal user with basic computer knowledge?   the installation cost so much  354 $   ouch!
T320 Server with no RAID/Controller, will it work?