GPU power supply fail?

Question

My question is: Can my GPU return an unreliable (randomly wrong) response due to slightly insufficient power supply but still operate without reporting error? I use the GPUs for machine learning as a mathematical processing unit so by unreliable response I mean calculation mistake. Like 2 + 2 = 6.
My hardware specs:

• Two ASUS GeForce GTX 1080 Titan, Founders Edition Board: ASUS ROG STRIX Z270G GAMING
• CPU: INTEL Core i7-7700K
• SSD: SAMSUNG SSD 960 Evo M.2, 500GB
• RAM: CORSAIR Vengeance LPX Black, 32GB
• Case: THERMALTAKE Core V21
• CPU cooler:be quiet! Pure Rock (15.50cm)
• PSU: CORSAIR RM750i, 750 Watt

The reason for asking is that the GPUs are - I believe - are taking max 300W each and my CPU takes 140W max. That's already 740W and my PSU is only 750W 80 Gold.

Answer 1

To quickly answer your question: a GPU can produce errors that aren't fatal to the system. Causes could include unstable power supply, faulty video RAM, driver issues, programming errors, PCI-E bus issues, etc.

While your symptoms could be caused by a power supply that can't keep up it's much more likely that something else is at work, especially if the rest of your system is running fine. Remember that the maximum power consumption values are rarely reached unless you're putting unrealistic synthetic loads on the hardware (e.g. Furmark).

Do remember that performing calculations on GPUs is quite different and may cause different results when working with floating point computations. I'm no expert in this matter though.