Is it possible to use two power supplies in one gaming computer?

Toggle sidebar Toggle sidebar
E

Elf_Knight

Honorable
Nov 9, 2013
650
1
11,015
Hi folks!

I just found out that my graphics card is SLI ready (the Zotac GTX 970) thankfully so now all I have to do is upgrade my motherboard and power supply for overclocking and SLI. I just got a good cpu cooler for my i5 4690k but I need more power. I was thinking about how the Corsair 900D case has room for two power supplies cause it is freaking huge! My case is the Fractal Design Core 2300. I was thinking that with a little bit of modding I could remove the CD drive bays since I don't use one any way. I have an external CD Drive if I need one and Steam of course. Anyhow basically I have enough space for a top mounted PSU or a bottom mounted PSU. Right now I have a bottom mounted power supply (EVGA 500 watts 80 +Bronze certified, etc) for my single card. I was wondering if I get a new motherboard if it is possible to simply buy a second 500 watt psu instead of replacing it with a higher wattage psu. That way I would have 1000 watts in my system and it should power 3-way SLI and overclocking. I am going to start off with 2-way SLI and save up for a third card. The 980 and Titans are too expensive. :( So yeah, that is my question: Is it possible to add a second power supply? Or can you only use one? Is it too dangerous for all the components to use two PSU's?

Many thanks in advance!!! :)
 
Solution
DonkeyOatie
A two part answer.

1. The GPU's PCIe power could be provided by a second PSU.
2. There is a flaw in your plan.

Your existing PSU is too low performance for the high-end gaming system you are building, os it needs to be replaced anyway. If you plan to 3-SLI, then your second PSU need to be able to drive all three GPUs, (because your existing one certainly cannot) I would want a good 750W PSU for that alone.

allowing for all the time it will take to mod. your case and fit a better power feed, it would likely be cheaper to upgrade to a decent, budget 1000W-ish PSU.
(3-SLI is very unlikely and has issues, trade-in your old GPUs and get Pascal or whatever is good then))

The EVGA B2-0750-VR is available for under $50 at the moent...
Sort by date Sort by votes
L

little_me

Splendid
May 9, 2015
1,670
39
21,740
Possible? from what I've read on these forums, yes. Safe? not quite. Also they wouldn't simply total up together, making load balancing another part to worry about.
Your best course of action would be to save for single, bigger, good quality PSU. If you want dual power supplies, they are completely different from standard PSU's.
 
Upvote 0 Downvote
E

Elf_Knight

Honorable
Nov 9, 2013
650
1
11,015


Because buying a 500 watt PSU is considerably cheaper than a 750-800+ PSU. I was trying to cut the costs a bit but I have done some more research and found out that it is a bit risky.

Otherwise, what would you say is the recommended power for 3-way SLI of 970's? I am starting off with 2-way SLI and will get a third later on. I will overclock them as well. I might get 2 more monitors so I want to run each monitor off each card and eventually get some sort of safe watercooling. Or maybe just loads of fans. I have room for about 4 more fans in my PC.

I have read online that 750 watts is enough but a single 970 needs 500 according to Nvidia specs. However I have seen Linus Tech Tips on YouTube use as little as 500 watts on things like a GTX Titan and a GTX 980.

Would you know what power supply I should save up for? It is very confusing.

Many thanks in advance!
 
Upvote 0 Downvote
Archaic59

Archaic59

Polypheme
Jan 6, 2015
10,038
648
69,240
You have a cheap entry level PSU to begin with. You need to replace it with a proper model of higher quality that has the power to meet your needs.

EDIT: 2-way SLI you need 750 watts and 3-way is 850 watts minimum. A high quality 1KW PSU would be a good choice.
 
Upvote 0 Downvote
DonkeyOatie

DonkeyOatie

Champion
Sep 16, 2014
12,141
1
50,960
A two part answer.

1. The GPU's PCIe power could be provided by a second PSU.
2. There is a flaw in your plan.

Your existing PSU is too low performance for the high-end gaming system you are building, os it needs to be replaced anyway. If you plan to 3-SLI, then your second PSU need to be able to drive all three GPUs, (because your existing one certainly cannot) I would want a good 750W PSU for that alone.

allowing for all the time it will take to mod. your case and fit a better power feed, it would likely be cheaper to upgrade to a decent, budget 1000W-ish PSU.
(3-SLI is very unlikely and has issues, trade-in your old GPUs and get Pascal or whatever is good then))

The EVGA B2-0750-VR is available for under $50 at the moent and will SLI two 970s very well. That's what I would use.

 
Upvote 0 Downvote
Solution
E

Elf_Knight

Honorable
Nov 9, 2013
650
1
11,015


Thank you for the informative answer! I will upgrade to an 800 watt power supply to be safe and give me some head-room for overclocking and 2 or 3 way SLI. I will do more research into Pascal because I do not know too much about it at the moment.
 
Upvote 0 Downvote
L

little_me

Splendid
May 9, 2015
1,670
39
21,740
970 requires 145W according to geforce.com, they do recommend 500W power supply though since.. computer has other parts also.
So.. basically, 970 needs 12A, +12V making 3 way sli want up to 36A on 12V rail. (or each gpu in it's own separate 12V rail)
That said, 750 to 850W PSU, should, on paper be already capable of doing 3 way sli with 970's.
Overclocking makes it more tricky though and with that in mind, you should not count on min-maxing on PSU capability.
Also seemingly most sub-1000W PSU's don't have more than 4 pci-E connectors, making 3 way sli trickier and meaning that you might need to go for bit higher.
http://pcpartpicker.com/part/seasonic-power-supply-platinum1000

That said, I don't fancy overclocking too much so my experience on the matter is limited and USAFRet has likely replied better than I can already.
 
Upvote 0 Downvote
DonkeyOatie

DonkeyOatie

Champion
Sep 16, 2014
12,141
1
50,960
145 - 150W is the normal 'steady-state' maximum, BUT the GPU is capable of generating sudden demand spikes of well over 200W. This extra power is normally provided from the PSU's capacitors (which is why gaming systems need high-performance PSUs) I would not SLI 3 970s on less than 850W for this reason, or drive them 'solo' from their own PSU on less than 750W. (even though some power would be provided from the motherboard)

There are many areas where I might cut corners to get my build, PSU is not one of them.
 
Upvote 0 Downvote
E

Elf_Knight

Honorable
Nov 9, 2013
650
1
11,015


3-way SLI sounds more and more risky by the minute to me so I will stick with 2-way SLI and an 800 watt psu. That should be enough, no? I found a good board on Amazon for 65 British pounds (my currency) that has overclocking and 2-way SLI which is a pretty good deal to me. Then an 800 watt power supply is doable if I get a sub-100 quid motherboard replacement. I have to get an LGA 1150 board though since my cpu requires an LGA 1150 socket :( I wish I had gotten an i7. I might get one later.

P.S. I was kind of disappointed to find out that a single 970 cannot run the Witcher 3 on Ultra (it is graphically modded) at a constant 60 FPS. I get 30+ to 40+ FPS Constantly though and it never dips below 30 so that is pretty good. I would like more FPS though and I might get more monitors. I think 800 watts should suffice for my needs.
 
Upvote 0 Downvote
toyftw

toyftw

Dignified
Jul 29, 2012
4,370
0
16,960


Hi - Plz post the model)s) you are interested in here before you purchase, just to dbl check you've selected
good quality. If you are going beyond 750 you prob should go to 850. You will find most (not 100%) of the time
the suppliers better models are the one's that end in 50, ie 650,750,850, the 500,600,700 are usually lower
on the food chain in terms of quality.
 
Upvote 0 Downvote
E

Elf_Knight

Honorable
Nov 9, 2013
650
1
11,015


I will do some research ahead of time before I buy a new power supply and post here to double-check. I was thinking of the Corsair RM850 watt Gold power supply. It has good reviews on Amazon and would definitely suffice for 2-way SLI with overclocking.
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom