Simple insert statements are taking so long
The performance problem it's because of your clustered index. When you use clustered, and you add a new record, it needs to physically rearrange all records in the table to make space for it. 

Drop the clustered index and create an unique non-clustered index instead. That should fix your performance problem.

As a general rule, I'd also recommend having a clustered index, but with only a numerical autoincremental id.