Gigabyte 980Ti G1 Gaming SLI - Is a 850w PSU enough?

[machumachu]

Hi guys,

I have a single 980ti rig now and will get a second one soon.
Will my Corsair HX850i PSU be able to handle 980ti SLI (Gigabyte g1 gaming)?
I found various answers for reference cards, but i couldn't find anything about g1 gaming model.

I overclocked it a bit (core voltage unchanged, power limit 111%, core clock +150mhz, memory clock +450mhz) and monitored my system with GPU-Z and Corsair Link while running Firestrike.

GPU-Z highest reading: Power Consumption: 100.9% TDP
Corsair Link: Power Out max 420w (Power In max: 455.6w, efficiency 89.31%)

Here are my specs:

Motherboard: Maximus VII Hero
CPU: 4790k @4.6ghz with a Coolmaster Nepton 140XL
GPU: Gigabyte GTX 980ti g1 gaming (core voltage unchanged, power limit 111%, core clock +150mhz, memory clock +450mhz)
RAM: 8gb x 2 Trident X @2400mhz
SSD: Samsung SSD850EVO 512gb
PSU: Corsair HX850i

Do you think my Corsair HX850i will be enough, or should I upgrade it?

Thanks in advance!

 

[bennyd87708]

With both of them overclocked, it would work but you would be cutting it reasonably close. Personally I think that you would be fine.

 

[fzacek]

I agree with the answer above. You're not going to have much more room to play with, but 850W will be enough.

 

[WyomingKnott]

I found this in a review: "As you would expect, power is sourced from two 8-pin power connectors capable of delivering a total 375W to the card once the PCIe slot is factored in. The GTX 980 Ti ships with a default 250W so there's plenty of electrical headroom. "

At worst, the two cards will draw 750 watts. Best to check the upper limit on your 12V rail! EDIT: I just did, the limit on the 12V rail is 850W and there are six PCI-E power connectors. Go for it.

 

[beekermartin]

I am running 2x780 Classifieds. With them both boosting to 1202 core and stock voltage I am pulling @650-680 watts according to my APC UPS. With them both boosting to 1306mhz and 1250mv it jumped to 750-775 watts!

I was surprised how much more power it pulled by overclocking. The 980ti does use a lot of power especially when overclocked. I would say if you overclock them to the max you will still be under 850w but you will be cutting it damn close.

 

[beekermartin]

BTW, we have very similar hardware. I am running with all cores boosting to 4.4ghz at 1.10 volts. You are at 4.6 and I imagine higher voltage. I think you are going to be pushing it very close to 850 watts. If you have a Kill A Watt meter check out how much it is pulling from the outlet.

 

[machumachu]

Thank you for your replies.
I understand that 850W should be enough but won't let me much room to play with.
Since I would like to run my rig for a few years and possibly upgrade it a bit, I am considering upgrading my HX850i to a HX1000i to avoid being to close to the limit, what do you think?

 

[machumachu]

BTW, we have very similar hardware. I am running with all cores boosting to 4.4ghz at 1.10 volts. You are at 4.6 and I imagine higher voltage. I think you are going to be pushing it very close to 850 watts. If you have a Kill A Watt meter check out how much it is pulling from the outlet.

We have a very similar hardware indeed!
My 4790k boosts at 4.6ghz at 1.19 volts. I don't have a Kill A Watt meter, but I guess I'll be very close to 850 watts.

 

[beekermartin]

Thank you for your replies.
I understand that 850W should be enough but won't let me much room to play with.
Since I would like to run my rig for a few years and possibly upgrade it a bit, I am considering upgrading my HX850i to a HX1000i to avoid being to close to the limit, what do you think?

I think that is a great decision! It is always better to have too much power than not enough.

 

[machumachu]

Thank you guys! This is my first rig and I'm glad to get quick and useful advice!

 

[machumachu]

Hi again guys,

I ordered a Corsair HX1000i to replce my Corsair HX850i, is it ok to change the PSU unit ONLY and keep the cables that are already connected to my rig?

I assume it should be ok considering it is the same brand / series but I would like to be sure...

Thanks!

 

[beekermartin]

I would just match up the cables and if they appear identical then you should be good to go.

 

[rcald2000]

I agree with Linus' philosophy about wattage recommendations. Granted, I'm sure he gets them for free, but I certainly don't. I over purchase on supplies wattage because I don't want to ever wonder if I have enough power. Also, I like the units with fanless modes, not turning on the fans yet, because my card's TDP is well under where the fan triggers. Also the efficiency is usually better at the 25%-50% of the amperage max load then nearing 100%.

https://mayrsom.files.wordpress.com/2012/12/frabz-power-unlimited-power-42e9d8.jpg?w=600

 

[machumachu]

I did some more search, and it seems the cables are compatible.
Indeed, Corsair cable upgrade kits indicate these cables are compatible with Hxi series:
"HXi Series – 1000/850/750"

http://www.corsair.com/en-us/individually-sleeved-ax-i-1200i-860i-760i-atx-24pin-generation-2-black