Re: PNY 260 overheating
Yes, it's normal. An open case won't net you all that much of a benefit.
Adjust the fan speed on your card with one of the software tools out there (like RivaTuner) for the heavy-hitting games. This should help.
i7-2700k @ 5.0 GHz
Nvidia GeForce 570 2.5GB Tri-SLI
Asus P67 WS Revolution (Tri-SLI)
OCZ Vertex SSD x 4 (Raid 5)
G.Skill 8GB DDR3 @ 1600MHz
PC Power & Cooling 950W PSU