Still having the problem on old hardware. 70-110 FPS until 5 minutes or so, after which it starts floating from 25-50 FPS.
CPU - AMD A6-5400K 3.6 GHz, OC'd to 4.5 GHz - Also happens with my AMD Athlon x4 750k in the same system, though I'm not currently using that CPU.
GPU - Nvidia GT 710 2gb
GPU Driver Version - 27.21.14.5671
Reproduction rate - Every single game for a couple months now
Zero Overlays, DX9 Legacy mode doesn't make a difference, CPU usage doesn't change noticeably during the frame drop time, and the GPU is never fully utilized.
I honestly assumed it was just my potato PC, considering my dated parts... But it runs great for the first few minutes, and I saw this post, so thought I might as well chime in and see about finding an improvement. I tried using the other (the better x4 750k) CPU for a bit to see if that made a difference since my CPU is...