The advantage to running a quad port card is that all of the VRAM is available for the display. When you run 2x dual cards, the memory usage is unequally configured between the cards and restricts part of the VRAM's allocation. That may or may not have an operational impact.
Yes, many times. Had them in all of my machines at one time until I upgraded to NVS 310 and P620. Recalling from memory (too lazy to look it up )... I upgraded my video cards because the VRAM in the 295 is only 256MB. UHD monitors require more. The NVS 310 is available in 512MB and 1GB. The P620, a quad, has 2GB... which is probably the minimum amount of VRAM anyone running 4 hi res monitors should consider.
Correction... I didn't uninstall "many" times, only a few when troubleshooting. To say many times sounds like I might have been having ongoing problems needing uninstall/reinstall of the driver. Such is not the case. My 295s ran mostly trouble free (as do my 310s and P620s.)
2GB VRAM is plenty for a trading rig. Likely not for gaming or video file work... especially if "across all 4 monitors".
My old rig had NVS 285 vidcard. The Nvidia driver was buggy and it crashed from time to time even though I clean installed each new update. I went with AMD vidcard this time around and it has been rock solid.
The 285 is a waaaay old card. I used them too. Even the 295s are 10+ years old. At some point, old technology isn't compatible with new hardware/OS. Any new-ish video card from AMD or Nvida is going to be "rock solid". (I've got Nvidia cards in all of my desktop workstations and an AMD card in my mobile workstation. All work smooth as a gravy sandwich. )
I picked up 4 x LG QHD 32" monitors on sale from Costco but can't get my FirePro W4100 to work with them at max "native" resolution (2560 x 1440 @ 75hz). The max resolution tops out at only 1920 x 1080 @ 60hz in Win 7 control panel (the resolution of my old monitors). I clean reinstalled the latest vidcard driver but to no avail. Do I need very high quality cables for QHD? Right now I'm running some cheapo mini DP to HDMI adapters from eBay. Any thoughts? Thanks. https://www.costco.com/lg-32"-class-qhd-ips-monitor.product.100793227.html