PSU for GTX 980 Ti SLI
PSU for GTX 980 Ti SLI
I am working with an i7 6700k (overclocked to 4.8Ghz), an ASUS STRIX GTX 980 Ti (single card overclocked to 1250Mhz) and a Corsair RMx 850w PSU. Everything else is standard.
I understand this topic has been discussed before, but I need to be sure about something.
The suggested wattage varies between 800 and 1000w. Using the extreme power supply calculator for my 980 Ti SLI configuration, the result shifts from about 700w to more than 900w when I adjust the core clock frequency from the default 1000Mhz to my current 1250Mhz setting.
Is it the overclocking that is mainly responsible for such a big difference in wattage estimates?
I’d like to keep my Corsair RMx 850w for now. Would it restrict my ability to further overclock the GPU in SLI? Also, do I have any way to check if my PSU is supplying enough power to the GPUs? Are there visible signs if the PSU isn’t delivering enough?
We utilize 850 watters for stock configurations and 1050 watters for water-cooled, highly overclocked setups. Yes, overclocking significantly increases the PSU demand. As observed, the power limiter operates at 20%, meaning it can now supply power at 20% above its rated capacity.
http://www.guru3d.com/articles_pages/msi...ew,35.html
You may also check this resource where the 980 Ti draws up to 359 watts at peak (293 in gaming). This spike is manageable as an average, with capacitors handling the surges.
http://www.techpowerup.com/reviews/Gigab...ng/28.html
And indeed, you can track GPU power usage...
The Watt's provided is merely an estimate, your actual usage might differ. Particularly when overclocking, you might need to boost the power going to the GPU. The extra wattage you're experiencing is likely due to the overclocking process itself. Still, it remains a prediction; for extreme overclocking, consider buying a PSU that can handle more watts.
In terms of stability, the situation depends on the level of overclocking you aim for. I believe the Corsair RMx850 will suffice, being quite reliable.
I'm currently running my 3-way SLI on an 850 Evga without any issues, but I haven't overclocked the GPUs.
Why would you wish to overclock multiple units? Don't worry about it, two at a time.
It's hard to picture why you'd need to overclock a 980 ti sli setup, but to address your question I don't believe it will require significantly more power, especially if you keep the voltage settings unchanged.
We rely on 850 watters for stock builds and 1050 watters for water-cooled, highly overclocked systems. Yes, overclocking significantly increases the PSU needs. As observed, the power limiter operates at 20%, meaning it can now supply power at 20% above its rated capacity.
You can find more details here: http://www.guru3d.com/articles_pages/msi...ew,35.html
Additionally, check this link showing the 980 Ti drawing reaching up to 359 watts peak (293 watts in gaming). This spike is manageable as an average, with capacitors handling the surges.
You can track GPU power using afterburner and measure wall power draw with a kilo-watt meter.
As for why you might want to overclock the 980 Ti, the most obvious reason is "because you can."
Techpowerup reported these FPS gains for the 980 Ti:
Gigabyte G1: 131.4%
Palit Jetstream: 129.7%
Asus Strix: 128.4%
MSI Gaming: 127.2%
Zotac Amp: 127.1%
EVGA SC: 123.6%
If you're gaming at 4K resolution, the numbers are still insufficient—currently, two GPUs can't reliably maintain 60 fps at 4K. For 144/165 Hz displays at 1440p, the average 25-30% overclock is advisable.