PC with Multiple Video cards for Video Display and Rendering (Cycles)

I’ve been a single video card user pretty much all my computing life, but recent issues with rendering in Blender (Cycles) has me looking at buying a second cheap and small video card for display-only purposes, and have the current one do all the rendering (if this is possible). Here are the main components in my PC as of now:

Intel i7 2600k @ 3.4 GHz
16 GB DDR3 1600MHz Ram
GTX 580 Classified 3 GB GDDR5

I recently created a small scene in Blender which often stops rendering midway through. I peeked into the console and it shows the Cuda error listed below (as described on this page): http://wiki.blender.org/index.php/Doc:2.6/Manual/Render/Cycles/GPU_Rendering

CUDA error: Unknown error in cuCtxSynchronize()

An unknown error can have many causes, but one possibility is that it’s a timeout. See the above answer for solutions.

Which then points to this:

The NVIDIA OpenGL driver lost connection with the display driver

due to exceeding the Windows Time-Out limit and is unable to continue.

If a GPU is used for both display and rendering, Windows has a limit on the time the GPU can do render computations. If you have a particularly heavy scene, Cycles can take up too much GPU time. Reducing Tile Size in the Performance panel may alleviate the issue, but the only real solution is to use separate graphics cards for display and rendering.

I’ve tried some of the things the page talked about, but nothing really works for me. I’ve tweaked it to render in smaller tile sizes, reduced the sampling, even dropped the light paths from Full Global Illumination to Limited, including using both the default settings and tweaked settings, I still get the issues.

On this page it talks about separating the graphics card for display and rendering (which seems to make sense to me), and it’s something I am willing to do. However I never dealt with multiple video cards before and I have some requirements of my own before I jump into this.

Question 1

I currently have 2 monitors connected to my GTX 580 and I actually wanted to connect a 3rd one, so would anyone know a good small and low cost video card just for this purpose (with 3 DVI outputs)? And would it matter if the card is another Nvidia or an ATI or anything else?

Question 2

If I had a smaller low powered card for displaying video only, would this effect the use of the GTX 580 for other applications such gaming, as in will the game only use the Display Card and not the more powerful 580?

Question 3

I am looking at this card here ( http://www.frys.com/product/7314594?site=sr:SEARCH:MAIN_RSLT_PG ) and I like that it has 2 DVI and 1 HDMI output for three total outputs, and I believe I can use a HDMI -> DVI convertor for my third monitor, though I am not sure if all 3 ports would actually display video at once.

The question I have for doing something like this, would there be a color issue with using the HDMI port for my third monitor when the other two are using direct DVI connections? All three monitors are exactly the same models from the same manufacturer. I am worried that maybe using the HDMI would result in different colors, contrast and brightness.

To add, all three monitors have both DVI and HDMI inputs.