GTX 1080 Ti SLI possibly overwhelming PSU

[aL_eX]

System Specs:

-CPU: i7 6800K @ 4.2GHz

-GPU: 2 x GTX 1080 Ti

-PSU: EVGA Supernova 850W P2

-Motherboard: Asus X99 Strix

-Storage: 1 SSD and 1 HDD

-RAM: 2 x 16GB 3000Mhz

 

I just got two GTX 1080 Tis and I noticed that in 3DMark Time Spy (and all the other benchmarks and games I tested) the power usage and overall utilisation of each GPU was at about 50% - 65%. When testing the GPUs separately, they would both reach 98% - 99% utilisation as expected. I'm assuming that it's because the PSU can't supply enough power, as the PSU makes what sounds like a faint coil whine when both GPUs are under load.

 

Should I return my PSU and get a 1000W or 1200W one instead, or is it possible that the issue is caused by something other than the PSU?

 

P.S. I thought about getting a power monitor to measure how much power is being drawn from the wall and seeing if this value is close to 850W. Would this be a good idea? Thanks in advance

[STRMfrmXMN]

6 minutes ago, aL_eX said:

System Specs:

-CPU: i7 6800K @ 4.2GHz

-GPU: 2 x GTX 1080 Ti

-PSU: EVGA Supernova 850W P2

-Motherboard: Asus X99 Strix

-Storage: 1 SSD and 1 HDD

-RAM: 2 x 16GB 3000Mhz

 

I just got two GTX 1080 Tis and I noticed that in 3DMark Time Spy (and all the other benchmarks and games I tested) the power usage and overall utilisation of each GPU was at about 50% - 65%. When testing the GPUs separately, they would both reach 98% - 99% utilisation as expected. I'm assuming that it's because the PSU can't supply enough power, as the PSU makes what sounds like a faint coil whine when both GPUs are under load.

 

Should I return my PSU and get a 1000W or 1200W one instead, or is it possible that the issue is caused by something other than the PSU?

 

P.S. I thought about getting a power monitor to measure how much power is being drawn from the wall and seeing if this value is close to 850W. Would this be a good idea? Thanks in advance

Isn't Time Spy a CPU benchmark...?

 

Anyways, 850W should be enough but I'd personally buy a 1000W PSU for that setup. If the system isn't getting enough power, however, it'll shut off, not suddenly limit GPU ability.

 

You can use a Kill-O-Watt to measure power requirements from the wall but note that this number doesn't account for efficiency.

[WereCat]

I very much doubt that 850W isn't enough for that. Even with heavy OC.

[phongle123]

Video will start at power consumption part of the video. According to Linus' video, 1080 used 250/252W while 1080Ti used 329/330W. So 500/504W for 1080 SLI and 658/660W for 1080Ti SLI.

 

According to this picture: a 4.4Ghz 6800k uses 177.1W, your overclock is 4.2 but lets just use 4.4Ghz instead.

 

So you're looking at 837.1W for the 1080Ti SLI with just GPU and CPU, before any other components and before adding in PSU Efficiency.

1080 SLI + 6800k looks like 681.1W.

 

EDIT: I mistook the full computer wattage as the wattage of the GPU. It should be around or more than the 250W rated TDP.

[aL_eX]

Just now, WereCat said:

I very much doubt that 850W isn't enough for that. Even with heavy OC.

Honetly, that's what I thought. But the coil whine from the PSU seems like a telltale sign. Maybe the unit is just faulty. I'll try and return it and get a 1000W PSU just to be safe.

[WereCat]

Just now, aL_eX said:

Honetly, that's what I thought. But the coil whine from the PSU seems like a telltale sign. Maybe the unit is just faulty. I'll try and return it and get a 1000W PSU just to be safe.

 

Go ahead and try. Maybe there is really something wrong with that PSU, or maybe it just degraded a lot for some reason.

[STRMfrmXMN]

1 minute ago, aL_eX said:

Honetly, that's what I thought. But the coil whine from the PSU seems like a telltale sign. Maybe the unit is just faulty. I'll try and return it and get a 1000W PSU just to be safe.

Coil whine isn't a mechanical fault. It's a noise. It doesn't make the PSU less capable.

[RadiatingLight]

1 minute ago, aL_eX said:

Honetly, that's what I thought. But the coil whine from the PSU seems like a telltale sign. Maybe the unit is just faulty. I'll try and return it and get a 1000W PSU just to be safe.

coil whine might mean it's getting close to it's limit, but doesn't mean it's not enough.

[aL_eX]

Just now, phongle123 said:

Video will start at power consumption part of the video. According to Linus' video, 1080 used 250/252W while 1080Ti used 329/330W. So 500/504W for 1080 SLI and 658/660W for 1080Ti SLI.

 

According to this picture: a 4.4Ghz 6800k uses 177.1W, your overclock is 4.2 but lets just use 4.4Ghz instead.

 

So you're looking at 837.1W for the 1080Ti SLI with just GPU and CPU, before any other components and before adding in PSU Efficiency.

1080 SLI + 6800k looks like 681.1W.

Thanks for the analysis. It seems like I'm cutting it really close. After restaring the computer, I noticed that usage reaches about 80% in the Heaven benchmark, but the coil whine from the PSU is becomes very loud when this is running. Would you recommend returning the PSU (as it is possibly faulty) and getting a 1000W PSU?

[phongle123]

4 minutes ago, aL_eX said:

Thanks for the analysis. It seems like I'm cutting it really close. After restaring the computer, I noticed that usage reaches about 80% in the Heaven benchmark, but the coil whine from the PSU is becomes very loud when this is running. Would you recommend returning the PSU (as it is possibly faulty) and getting a 1000W PSU?

If you can possible return it for full price then do it and pay the extra 20$ or 30$ for a higher rated PSU. IMO, you always want to use a maximum of 80% of the PSU, meaning if your PSU is 1000W with 90% efficiency meaning 900W, you only want to use 80% of 900W which is 720W if you want to keep your PSU lifespan the rated amount or as long as possible.

 

But if it peaks past 80% that is fine but you don't want it to be using >80% all the time.

 

Not all PSU's will Coil Whine when they reach high usage, just like most GPUs won't coil whine when being used at 100%. There are exceptions to this however, and my GPU being one of it. It coil whines at high usage which sucks. But Coil Whine is not a returnable defect either. Some reps. will allow it because they are nice or unknowledgeable.

[aL_eX]

5 minutes ago, phongle123 said:

If you can possible return it for full price then do it and pay the extra 20$ or 30$ for a higher rated PSU. IMO, you always want to use a maximum of 80% of the PSU, meaning if your PSU is 1000W with 90% efficiency meaning 900W, you only want to use 80% of 900W which is 720W if you want to keep your PSU lifespan the rated amount or as long as possible.

 

But if it peaks past 80% that is fine but you don't want it to be using >80% all the time.

 

Not all PSU's will Coil Whine when they reach high usage. But Coil Whine is not a returnable defect either. Some reps. will allow it because they are nice or unknowledgeable.

Thanks for the suggestions. I just remembered that I'm using the power cables from a Corsair PSU I had before, instead of the Evga power cables. I noticed that the VGA connector that goes into the PSU has is missing a metal part on one of the pins on the Evga PSU cable, whereas the Corsair cable (currently in the system) does have a metal bit. In other words, the PSU cables look different. I'm going to try and use the correct cables, and see if this makes any difference (although it probably wont)

[quan289]

12 minutes ago, phongle123 said:

If you can possible return it for full price then do it and pay the extra 20$ or 30$ for a higher rated PSU. IMO, you always want to use a maximum of 80% of the PSU, meaning if your PSU is 1000W with 90% efficiency meaning 900W, you only want to use 80% of 900W which is 720W if you want to keep your PSU lifespan the rated amount or as long as possible.

 

But if it peaks past 80% that is fine but you don't want it to be using >80% all the time.

 

Not all PSU's will Coil Whine when they reach high usage, just like most GPUs won't coil whine when being used at 100%. There are exceptions to this however, and my GPU being one of it. It coil whines at high usage which sucks. But Coil Whine is not a returnable defect either. Some reps. will allow it because they are nice or unknowledgeable.

 

A quality 1000W PSU outputs 1000w regardless of efficiency, as well as they will be rated for continuous rated power - not peak.

17 minutes ago, phongle123 said:

Video will start at power consumption part of the video. According to Linus' video, 1080 used 250/252W while 1080Ti used 329/330W. So 500/504W for 1080 SLI and 658/660W for 1080Ti SLI.

No, it's not "658/660W for 1080Ti SLI". What you just did was doubling the AC power consumption from the wall for the ENTIRE system (meaning you are calculating two CPUs, two motherboards, two sets of RAMs, etc).

[phongle123]

9 minutes ago, quan289 said:

 

A quality 1000W PSU outputs 1000w regardless of efficiency, as well as they will be rated for continuous rated power - not peak.

Please Read again.

9 minutes ago, quan289 said:

No, it's not "658/660W for 1080Ti SLI". What you just did was doubling the AC power consumption from the wall for the ENTIRE system (meaning you are calculating two CPUs, two motherboards, two sets of RAMs, etc).

I see that is the whole system rather than just the GPU. Thanks for correction. I thought it was just GPU. Okay so, then let's just use 1080Ti's TDP of 250 as the total Wattage.

http://www.anandtech.com/show/11180/the-nvidia-geforce-gtx-1080-ti-review/16

[aL_eX]

3 minutes ago, phongle123 said:

Please Read again.

I see that is the whole system rather than just the GPU. Thanks for correction. I thought it was just GPU. Okay so, then let's just use 1080Ti's TDP of 250 as the total Wattage.

http://www.anandtech.com/show/11180/the-nvidia-geforce-gtx-1080-ti-review/16

OK, here's what I'm going to do: I'll order a power meter off Amazon (should arrive between the 14th and 16th of March) and report back with my findings.

[phongle123]

14 minutes ago, aL_eX said:

OK, here's what I'm going to do: I'll order a power meter off Amazon (should arrive between the 14th and 16th of March) and report back with my findings.

 

And here we go, found this website saying 1080 SLI is 364W so add the 177.1 = 541.1W for 1080SLI+4.4Ghz 6800k at peak usage.

http://www.guru3d.com/articles-pages/geforce-gtx-1080-2-way-sli-review,4.html

 

It only states that a 750W is recommended for 1080SLI.

 

If anything, try to get a replacement for your PSU. Since 750W is the recommended, your 850W PSU shouldn't whine.

 

Also, since the 1080 uses 184W from the website link. Going by Linus' Power consumption for 1080 @252W and 1080Ti @330W and since they are using the same components except for GPU. The GPU wattage difference between the 1080 and 1080Ti should be 78W. So 1080 Wattage of 184+78= 262W for 1080Ti.

So 262+262+177.1 = 701.1W hypothetically just for the 1080Ti Sli and 4.4Ghz 6800k.

[quan289]

 

29 minutes ago, phongle123 said:

Please Read again.

You said:

"IMO, you always want to use a maximum of 80% of the PSU, meaning if your PSU is 1000W with 90% efficiency meaning 900W, you only want to use 80% of 900W which is 720W if you want to keep your PSU lifespan the rated amount or as long as possible."

 

Basically, you are saying that if you got a 1000w, it's only a 900w PSU because of efficiency. And using your ideal 80% limit, you should keep it at 720w max.

 

Any proper power supply will be rated at DC output - not AC input. As such a quality 1000w will be able output 1000w continuously to your components within its warranty period, while drawing up to ~1111wAC at the wall if it's 90% efficient at that load.

 

29 minutes ago, phongle123 said:

I see that is the whole system rather than just the GPU. Thanks for correction. I thought it was just GPU. Okay so, then let's just use 1080Ti's TDP of 250 as the total Wattage.

It would be helpful if you source which benchmark you got this. Anandtech tested that 1080 FE with an "Intel Core i7-4960X @ 4.2GHz" as shown here. Since it is 403wAC at the wall, that's approximately 370wDC (give or take depending on the PSU's efficiency at that load). Typically, the second GPU would draw a little less in a SLI configuration, but such a setup would be using around 600wDC during gaming load. The EVGA Supernova 850W P2 is a quality high-end unit that shouldn't have any problem outputting 70% of it's rated continuous power

[PSUGuru]

according to PCPartpicker, which generally overstates the Wattage reqs, you need about 700-750 watts to power everything. However, If you want to expand, I suggest a 1000 watt system. That should be more than enough.

[PCMasterDebater]

The advice on this forum still amazes me. People with absolutely no experience interjecting their opinion cause they "think" they know enough to help.

 

850w PSU isn't enough for this setup. If you think it is, a simple google search and 1 hour of your time would be incredibly informative and would avoid any of this "its enough" nonsense.

 

If you are a real PCer, you would have a watt-meter handy, understand what PSU efficiency means and how to correctly identify what PSU is needed for your setup. Dually so when considering the hardware the OP is working with.

 

OP, how do you not know any of this already with that sorta hardware? Its mind boggling brother. Mind boggling.

[IceCold008]

I have a general rule if your going to SLI anything get a min 1200 watt PSU.  I myself have a 1250 watt PSU. Yes GPU's are getting low power consumption these days but you have to take anything else into consideration, thats includes all your hard drives, SSD, everything including your Monitor. And make sure you have enough headroom if you want to add more stuff to your pc in the future. Getting a PSU which only just manages it, Aint cutting it these days. More power the better. 

[quan289]

3 hours ago, PCMasterDebater said:

The advice on this forum still amazes me. People with absolutely no experience interjecting their opinion cause they "think" they know enough to help.

 

850w PSU isn't enough for this setup. If you think it is, a simple google search and 1 hour of your time would be incredibly informative and would avoid any of this "its enough" nonsense.

 

If you are a real PCer, you would have a watt-meter handy, understand what PSU efficiency means and how to correctly identify what PSU is needed for your setup. Dually so when considering the hardware the OP is working with.

 

OP, how do you not know any of this already with that sorta hardware? Its mind boggling brother. Mind boggling.

Considering how he is powering said setup shows that a quality 850w PSU is capable of powering it.

[Flavio hc 16]

 

850w is not enough for that setup under oc, this LTT video shows it, and also my experience ( i have a 5820k and 2 980ti, everithing with oc). I have burned 2 850 psu before getting a corsair rm1000i . From when i had upgraded the  psu i haven't  got any problem

[stealth80]

On ‎11‎/‎03‎/‎2017 at 9:15 PM, aL_eX said:

System Specs:

-CPU: i7 6800K @ 4.2GHz

-GPU: 2 x GTX 1080 Ti

-PSU: EVGA Supernova 850W P2

-Motherboard: Asus X99 Strix

-Storage: 1 SSD and 1 HDD

-RAM: 2 x 16GB 3000Mhz

 

I just got two GTX 1080 Tis and I noticed that in 3DMark Time Spy (and all the other benchmarks and games I tested) the power usage and overall utilisation of each GPU was at about 50% - 65%. When testing the GPUs separately, they would both reach 98% - 99% utilisation as expected. I'm assuming that it's because the PSU can't supply enough power, as the PSU makes what sounds like a faint coil whine when both GPUs are under load.

 

Should I return my PSU and get a 1000W or 1200W one instead, or is it possible that the issue is caused by something other than the PSU?

 

P.S. I thought about getting a power monitor to measure how much power is being drawn from the wall and seeing if this value is close to 850W. Would this be a good idea? Thanks in advance

PSU question aside, how is the CPU utilisation during your tests and at what resolution are you playing? 850w quality PSU is capable of running your rig, but its probably not in the realm of the PSU's efficiency bracket and therefore I wouldn't push any overclocks on it. You could try lowering the clocks on the CPU if the CPU utilisation isn't high in your tests - that should reduce the power draw a little - but as already said, probably best to return and get yourself a 1000w platinum.

 

I'm not fully convinced the PSU is causing your issue though

[aL_eX]

1 hour ago, stealth80 said:

PSU question aside, how is the CPU utilisation during your tests and at what resolution are you playing? 850w quality PSU is capable of running your rig, but its probably not in the realm of the PSU's efficiency bracket and therefore I wouldn't push any overclocks on it. You could try lowering the clocks on the CPU if the CPU utilisation isn't high in your tests - that should reduce the power draw a little - but as already said, probably best to return and get yourself a 1000w platinum.

 

I'm not fully convinced the PSU is causing your issue though

The CPU usage is about 30% - 40% and I'm playing at 1440p 165Hz. I'll try and bring the CPU back to stock frequency and see what difference it makes, but I'll probably do that tomorrow after my power meter arrives (which will definitely shed some light on the problem).

[aL_eX]

9 hours ago, PCMasterDebater said:

The advice on this forum still amazes me. People with absolutely no experience interjecting their opinion cause they "think" they know enough to help.

 

850w PSU isn't enough for this setup. If you think it is, a simple google search and 1 hour of your time would be incredibly informative and would avoid any of this "its enough" nonsense.

 

If you are a real PCer, you would have a watt-meter handy, understand what PSU efficiency means and how to correctly identify what PSU is needed for your setup. Dually so when considering the hardware the OP is working with.

 

OP, how do you not know any of this already with that sorta hardware? Its mind boggling brother. Mind boggling.

I've ordered a power meter that should arrive tomorrow (will report back with results). I actually never intended on getting an SLI setup, so that's why I went for a 850W PSU in the first place.

[quan289]

2 hours ago, aL_eX said:

I'll probably do that tomorrow after my power meter arrives (which will definitely shed some light on the problem).

TBH, even if you were to get the power readings from your meter, it wouldn't explain your issue (you could used it if you feel the need to replaced it - I don't think you do). There isn't any sort of data connection between the PSU and your system that make your GPUs detect what power supply you are using. The PSU is supplying power to your system on demand. If your GPUs demands a 600wDC power draw for that application / instance, it will draw 600wDC regardless if it's 750w or 1600w. If it exceeds what the PSU is design to be able to output, it is the PSU job to cut power to the system via the safety protections integrated in the PSU ( for example, Over Power Protection / OPP), which your system is still running and able to complete all of its tasks.

 

Of course, a low quality (which the 850 P2 isn't) or defective PSU can lead to stability issues such as your system crashing / locking up; however, it shouldn't be affecting your system performance in that sort of manner. There's a possibility of a driver issue, as well as your situation remind this thread on reddit where s/he saw both low CPU and GPU usage but fixed it with an CPU overclock : https://www.reddit.com/r/nvidia/comments/3pob04/are_my_980_tis_in_sli_only_supposed_to_be/