It really bothers me that people are spreading false information, here is picture proof that dual wielding can have a huge impact on your DPS. I am not buffed in any way these are just my characters stats.

Take a look for yourself people.

As you can see from the first to last two frames, the dps dropped significantly having only one of the weapons equipped.

These is a formula in place and you have to take advantage of it, 15% attack speed is a HUGE buff when you have two equally powerful weapons. Do not take it lightly. I am not saying everyone should dual wield as a shield does offer more protection but saying it does not give you more DPS is fucking bullshit.

I posted the following in response to another comment also:

This is simply not true, I found an amazing weapon during the end of nightmare and it doubled my DPS when equipped, when I removed my crappy offhand weapon my dps dropped only by like 20 points so I equipped a shield I had with a ton of +dex. A little later I found a comparable weapon to my main hand and dualed it and received a significant dps boost. If you have two similarly powerful weapons then dual wielding will ALWAYS give you more dps then a shield. Especially if they both have gem slots for bonus damage. The shield is a better option only when you have one weapon that is significantly better then the other. As far as the numbers go at the point i was playing i think I had only about ~550 dps and when I found the first weapon I jumped to ~900 with the shield and when I found the second good weapon I again jumped to around ~1200. While there may not be a direct damage increase there sure as hell is a direct damage per SECOND increase as a result of the attack speed.

EDIT: I don't care about karma but I would appreciate if this could be upvoted so people can see.