The 760 GTX on one of my machines has seen a precipitous drop in framerate. It is now running < 50 FPS compared to the 1050 (~80 FPS) and the 1060 (90-120 FPS).
Is this due to a recent update? Could the card have been corrupted?
Previously, the 760 card was running at ~70-80 FPS.
760 should be around 5-15% slower than 1050. So the numbers you expect do add up. Are we talking about an empty scene? I can imagine certain visual elements be more taxing for older architectures.
You did not mention the specifications of the cards, the resolution, complexity or composition of the scene in question. For example: both 760 & 1050 come with 2GB video RAM as standard. However, there are 4GB 1050s as well. Perhaps you own the beefier one.
In a basic scene 760 & 1050 shouldn’t really outperform one another by much; in a complex scene, on the other hand, a 4GB version of 1050 will outperform the 760 by quite a margin providing the vRAM requirement is greater than 2GB.
Running out of vRam will have a dramatic effect on the way video card handle data.
The 760 GTX on one of my machines
Do you have more than machine with 760? Perhaps the issue is elsewhere, an overheating CPU can throttle and bottleneck what the video card can do.