Need replacement vid card recommendation

I have a 2010 Mac Pro; it came with an ATI Radeon HD 5770 video card. I am currently using it with three monitors.

I believe the video card is on its way out; every now and then, one of the monitors will go blank (as if receiving no signal). Rebooting usual fixes this. I know it is the video card and not the monitors that is causing the problem (by swapping out the monitors).

Anyway, I cannot afford a new 5770 or 5780 video card. I like having multiple monitors, but I do not need a "high end" graphics card. I never do any gaming; this computer is for work only.

So my question is: what should I look for in a replacement video card? The current video card uses a "double wide PCI Express". So is that what I should look for in a replacement video card? Even better, does anyone here have specific video card recommendations?

I thank you all in advance for advice or insights.