re: To upgrade, or not to upgrade...... my video cards....

5400 chipset. Looks like they do have Dual Xeons, though, but dell lets you customize. I guess they are either E5430s or E5450s.

If it's using SATA 1.5Gbps, the SSDs might be bottlenecked by that limited throughput there, and that can contribute to some slowdowns, depending on the task (but still, they're going to be faster than a traditional HDD, especially one from that era).

Depending on the issues with the current systems, it could be time to do a larger overhaul, and I'd suggest a custom-built workstation (and I'm always up for the job!) for the long haul. More modularity with a bigger case, universal fit, room for additional drives, multiple pro GPUs if necessary, full bandwidth of the SSDs, higher quality PSUs, better cooling, etc.