Bongo

Thermaltake W0117B 750W MSI B360M PRO VDH Intel Pentium Gold G5400 DDR4 2666Mhz 8GB RAM 1TB SSD Geforce 1050ti 4GB Asus Cerberus (new) Geforce GTX 260 BFG OC (old) Installed new graphics card today 1050ti, following which I am getting random pc shutdown restarts without warning. System completely stable with old card (GTX 260). New card is "unplugged" so only connects via PCI-e slot on the mobo. Is my power supply failing or just inadequate (it is over 10 years old)?