I just bought and installed the Nvidia Nvs 810 card. Manages 8 independent displays, lower power requirements and very performant. So far so good. . .
You don't need NVS. My GTX 960 for example has 4 ports, 2x DVI and 2x HDMI which means it runs 4 monitors provided they have the connectors (most monitors do). It has 2 fans which idle when not gaming (they're completely silent anyway). It's nice to have 3D capability should you want it... NVS cards are intended for heavy rendering, that's why they are pricey.
Agree if you only need 4 monitors today, no need to waste money. But if one wants to have expansion capabilities then I recommend the NVS 810 card. By the way this particular card is not intended for graphics rendering but geared towards advertisers or businesses which look to place multi panel screen walls. Its the new card of choice for most bank trading rooms I hear... What I very strongly discourage is to mix video card brands or use fairly old cards, even combining it with the internal GPU (if your motherboard has one). I have for years dealt with compromises and trade offs. Running AMD and NVidia alongside was never a perfect solution, nor running several older NVidia cards worked perfectly and also a combination of NVidia cards and internal Intel GPU was only a compromise. Think about all possible issues: Windows OS updates that often messed with drivers and Sleep/Wakeup and Hibernation issues. Think about shifted screens, messed up desktop positions. Also a problem you may encounter with your solution, @d08, the 4th outlet of your video card is most likely a Display Port (mine is on my GTX980 Ti). There is an issue (not sure only with my revision or in general) in that the video card powers one of the power pins (which it is not supposed to). For anyone who does not always want that screen on all the time (I have 9 screens and over the weekend turn most off when I only do development work), as soon as you switch off the display that is powered via that particular display port, Windows removes the whole display from its settings and it messes up all other desktop placements and app window positions. It has to do with the fact that the video card sends power to the display port connector. You can google it, it took me long time to figure out the culprit. Hope it saves someone else hours of headache. Given that many people spend thousands on trading education or data, I find 600 USD for a perfect graphics card solution a very cheap price to pay. The less cards, newer cards, same brand cards, the better.
Nvs was the traders choice as they were fanless. Later models added fans but the older models of the four way are $30 to $90 on eBay.
NVS are just dual, quad and octa 2D graphics cards. You want to do rendering on a 3D card which are much more expensive.
You're right in that the newer certain NVS cards were intended for simple 2D graphics. The Quadro NVS lineup in general is focused on CGI and CAD though - you wouldn't use a consumer class card for it (Radeon/GTX). You could just as well have 2 GTX1050 cards for a fraction of the cost and could still do 8 monitors - I don't really see a downside. NVS series is a moneymaker for Nvidia, it's not like you really get anything extra - the GPU is the same as in the GTX line as I understand. I have a different model and it's 2x HDMI, 2x DVI, I took a look today.
Quadro for rendering http://www.nvidia.co.uk/object/quadro-desktop-gpus-uk.html NVS the standard for multi display graphics http://www.nvidia.co.uk/object/nvs-graphics-cards-uk.html You are confusing two different product lines.
The NVS 420, NVS 440, NVS 450 are "Quadro NVS". It's Nvidia's naming convention which seems quite random to me.