Sultan: no, there is no internal tube in this reservoir. So the top inlet port directs the water tangentially, greatly encouraging the rotation of the water. I would guess an internal inlet tube could eliminate the vortex. There's not really a place to install one though.
Veii: LOL, I never thought about that vortex being a visual treat! My only reason for concern about it is that yes, it directly introduces whatever air is in the reservoir above the water into the output port, from where it goes directly into the pump. I'm pretty sure this hurts the pump efficiency and may ultimately cause wear or damage to the impeller.
But I'm posting this to learn; if such vortices are common in watercooled systems, and if the train of air bubbles is not hurting the pump, then I guess I wouldn't be concerned with them. When I ordered the PrimoChill reservoir I saw that they offered the Vortex Killer for their direct-mounted-pump versions, so I assumed vortices must only be a concern when the pump is so close by.
I do plan to run at reduced pump speed once the mobo is connected and I can control the PWM input. Actually, now that I think about it, I also have an Aquaero 6LT in the system, which I haven't wired up yet. I think I should be able to give that juice from the PS and connect USB to another computer and use that to control the pumps.
I suppose this discussion leads to my next question about how to you decide on the appropriate flow rate when you have PWM pump(s)?
If noise level doesn't drive this, would there be reasons not to simply run full tilt? Like, IDK, velocity erosion in the blocks or fittings?