Is there any 'tech savvy way' to confirm whether or not these cards are strictly incompatible together? (like via the specs or something) When I install the p620 drivers those 4 monitors work, but when I try to install the 300 drivers they don't (or actually one of them was still working for some reason which is even weirder). They are both Nvidia cards so I figured there wouldn't be a compatibility issue, but the 300 card is quite a bit older so maybe Nvidia will only allow you to have one of the driver sets functioning at any given time?
The NVS 300 went end-of-life with the Release 340 drivers. i.e. it won't work in any version above this. https://nvidia.custhelp.com/app/ans...ol-windows-driver-support-for-legacy-products The P620 is only supported in release 384 and above (released March 2018). You can't use two different releases of NVIDIA drivers together. A while back I upgraded to large monitors and single RTX 3080 card with 4 outputs, and I can run various intense GPU-accelerated machine learning systems using it as a bonus, and retired my old workstation cards. My motherboard has multiple PCIe x16 slots, so I can always add another card if I want to, for more outputs. For non-ML use, you'd probably be fine with a RTX 3050, which would be a about 4 times quicker than the P620 anyway.
Probably not technically correct.... I doubt you can even install 2 different drivers at the same time these days. For quite a while Nvidia has produce a "universal driver". It's like 450MB now. It's to run most/all Nvidia cards for when the driver is current. When you install the driver, it picks out the "parts it needs" for your card(s) and installs that onto your storage drive. So... if you're going to run different model cards at the same time, search the compatibility ("also supported" list) to see where both cards are listed for any version of driver. In general... if you're running 2 or more cards together, best they be of the same model... though all Nvidia NVS and Quadro cards are backwards compatible "up to a point where one is too old". (On one machine years back, I ran 4 video cards... all the same model, of course.)
If you need more than 4 monitors (and you don't need an additional 4 monitors in your rig), suggest you check out the NVS 310 instead of the 300... get the 1GB version. For being newer, they will/should be "more" compatible with the P620. 310s go for ~$15 on eBay. I've used them a lot and they work just fine even on UHD monitors.
Awesome, really appreciate the suggestion. I think for now I might just stick with the 5 I have running (4 on the 620 + 1 onboard), I'm down 2 from what I am used to but it could potentially be more beneficial to have less information in front of me in terms of the mental fatigue aspect etc.. worth trying out for a little bit at least, could be a blessing in disguise. Today is day #1 with my new system up and running after starting to this process over a month ago, thankfully it's running a million times better than my old system (no lag anymore) - thanks for all the help.