RAID Background Init Process : How To Disable It? How to Stop It?

Background Initialization occurs the first time you set up your raid configuration and then later if you require a rebuild on a failed disk.  You can alter the Rebuild/Initialization rate with Array Manager by right clicking on the controller and selecting the rebuild rate option.  50% is usually a good option for servers in production environment.  Background initialization will slow down your IO performance but not dramatically unless you commit your rebuild rate to 80-100%. 

Rebuild Rate option affects Consistency Checks/Background Initialization and Virtual Disk/Container rebuilds in the event of a failed disk.

Is there a way to disable it?

Not that I know of.

Is there a way to stop ?

Yes, if in windows right click on the controller in Array Manager and select "Stop Consistency Check"  At this time Consistency Check and Background Initialization are one in the same.

I thought, it is all right to use a RAID drive without having to initialize it.

It is "all right" but it is not by any means recommended.  Without a full Init/Consistency check the controller has less to work with in determining irregularities.

This I believe interferes in benchmarking: our results are inconsistent, and far below expected.

Yes, it will affect a benchmark.

I also do not how long this background initialization process takes to complete (if at all completes) for a 700-GB Logical Drive.

I would estimate about 24 hours for a 700gb logical drive unless you ramp up the rebuild rate in Array Manager which will lessen that time dramatically.