T3610 video card upgrade?

Hi, you don't mention what graphics card is currently in your T3610.

The T3610 has a 300w combined maximum for the PCIe slots and either a 685w or 425w PSU, hopefully yours has the higher watt PSU.  This is sufficient to be able to install some very good graphic cards.  . lists all the original equipment video cards that could be ordered with a new T3610.  In addition, you can also use certain modern consumer video cards, just choose types that are lower power and that are the correct size to fit the case.

 I had a 95w Nvidia GTX 1060 in a Precision T3500 that worked great.

Here is a link to the Owner Manual:  https://downloads.dell.com/manuals/all-products/esuprt_desktop/esuprt_dell_precision_workstation/precision-t3610-workstation_owner%27s%20manual_en-us.pdf

 I have the 685W power supply and I have dual firepro 5000 cards.  CPU is Xeon quad core E5-1607 v2. 16 GB RAM. Planning on RAM, CPU,  and GPU upgrades.  Alternatively, am I just better off building a new machine? . Using for 4K editing, effects and light use of MAYA.  Thanks!

Well, the first problem you might try to solve is finding a suitable video card that will actually fit in the T3610.  When I installed the Nvidia GTX 1060 6GB in my T3500 it was necessary to measure the PCI slot area for length and height, some video cards are simply too big in one dimension or another.  Your PSU can handle a very good video card as long as you stay in the wattage range that your entire setup uses, minus 10-20% for overhead.  Then there is the heat aspect to be aware of but if you are running dual Firepro 5000's already...

Is it cheaper to just build a new computer?  It might be, but I bought a used T7610 with dual 8-core @ 3.4 GHz, 128GB RAM and installed a GTX 1080Ti, is it a powerhouse and cost considerably less than building a new equally equipped computer from scratch.  Even in that big case I still had to find a video card that wasn't too tall (width?), otherwise the side cover would not close.

Remember, these are just my opinions and you know what those are worth.

This is what I had in the T3500 - EVGA GTX 1060 6GB, no cooling problems under hard use:

I have a 685 PSU and a Nvidia k2000 GPU any good upgrades

Good luck finding a video card.   I have a Nvidia 1080 GTX in mine works great.   You need to buy a new dell 8 pin to 8 pin or 8 pin to 8/6 pin to hook up to a GTX 1080.   Don't use the dual 6 pin cable.