Ah, okay.
My assumption is that it's a Corsair CX600 or CX600M: Not the greatest quality. Combine that statement with the fact that the Gigabyte Xtreme gaming has a peak gaming and maximum power consumption of 250 watts and 309 watts respectively, according to a TechPowerUp review (
https://www.techpowerup.com/reviews/Gigabyte/GTX_980_Ti_XtremeGaming/21.html ). Personally, I wouldn't upgrade to a 980 Ti, especially that high powered version of it, without upgrading the power supply. The purchase price of a quality power supply could very well exceed the price difference between the 980 Ti and GTX 1070.
Request: I'm aware that your initial question was a seemingly simple one, but would you mind stating your full specs?
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power supply tier (quality) list ***
http://www.tomshardware.com/forum/id-2547993/psu-tier-list.html
Corsair: CX / CXM Channel Well Technology
Tier Four
Built down to a low price. Not exactly the most stable units ever created. Very basic safety circuitry or even thin gauge wiring used. Not for gaming rigs or overclocking systems of any kind. Avoid unless your budget dictates your choice.
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power requirements for graphics cards ***
http://www.realhardtechx.com/index_archivos/Page362.htm