Just a general question, which configuration makes the PSU pull more wattage out the wall, ie work harder. SLi 980Ti both at 1.112 core voltage + a 325W power target. SLi 980Ti both at ~1.18 core voltage + default power target (275-300ish). Asking this as my 850W PSU seems to be a bit on the edge for SLi 980Ti + 6700K@ 4.8GHz. At times when I experiment with custom vBIOS' and run Timespy, the fan of the PSU ramps up pretty high to cool the PSU down. Never happened with a single 980 Ti.
Power target is just the ceiling of how much power the GPU can draw before throttling its Boost clock. Raising voltage will hit cause the GPU to hit this ceiling faster so if you can, use as little voltage as possible and as high a power target to allow the best headroom for the Boost clock to keep its maximum. Programs like HWinfo64 or GPU-Z can give you an idea of how much power your GPU's are drawing on full load. Hopefully you didn't go hogwild on your video bios' voltage entries, but each GTX 980 Ti has a TDP of 250w by default and the default power target maximum is around 300w. So two of those at full load plus a 4.8ghz 6700k (which is an above average overclock so probably pulling 100w+ when its fully loaded as well) would put you around 650w - 700w depending on how well the application you are using takes advantage of your hardware. Obviously two cards draw more power than one so if you are worried you are going to overload your PSU, decrease the power target to where there is a balance of playable framerate, but lower power consumption.
On my build I've used near 1kw on witcher 3. Granted X99 uses more power but you are probably pulling 800watts at the wall, which means your PSU is near ~80% capacity. Normal for fans to run at that kind of usage.
Yah when I had 980Ti SLI setup & i7-6700K here I had to upgrade my power supply when I start messing with higher power limits in a custom BIOS. Not to mention pushing my CPU to higher overclocks higher too. Originally I had a 750W Corsair PSU and it was fine with my CPU at 4.4Ghz (stock voltage) and the 980Ti's with the stock BIOS with mild overclocks. I have a UPS which has an LCD to show power draw and it was usually in the 600-650W range when running a game or benchmark with both GPUs at 99% with that setup. When I eventually ramped my CPU up to 4.6Ghz@1.3v and used a Custom BIOS for 320W max on the 980Ti. Granted I never saw the cards hit the max power draw but I'd guess they were pushing very close to ~300W each. Anyway shortly after putting that BIOS on my cards I noticed occasionally my PC would just hard power off. I decided to run 3DMark Firestrike and looked at my UPS while it was running. Sure enough PC shut off right as it showed about ~760W power draw. Which considering it was a 750W PSU I'm not surprised it decided it had enough. lol I got a 1050W power supply that solved my issue and when I re-ran tests I showed the damn thing would max out at around 790-800W power draw if both the CPU & GPUs were both cranked at near ~95-99% load with the 4.6Ghz o/c and both 980ti with the custom BIOS pushing about ~1500Mhz on both. It's been awhile since I had those but I remember eventually I went back to a lower wattage BIOS I think 275W or 300W as they just got too hot in SLI with the high voltage. The thing you do need to remember with power supplies is a 80+ Gold certified PSU must hit 90% efficient in it's range normally at 50% load. So basically with a 850W PSU, operating below ~765W power draw is where it is most efficient. Above the 765W mark it will start making a lot of heat which will start ramping up your PSU fans to keep it cool. Based on my own experience you're likely pushing close to 780-800W so it's making that power supply run hot when you really push it.
Ok, thanks guys these cleared things up quite a bit. I've had a couple of shutdowns as well. If I run both cards on 1.18 volts and a 325 power target BIOS' the PC/PSU will shut itself down under heavy load (Timespy, TW3 etc.) PSU fan spins up, not just some 1400ish rpm, sounds more like a damn GT-R and then - instant shutdown. Other times, while playing, it would just shut down with no fan engagement. At the moment I'm using the stock BIOS' on both cards, except I raised the max boost clocks in the BIOS of the 2nd card (STRIX 980Ti) as on stock BIOS the boost clock is hard limited for some odd reason uke2: So right now both are at 1405/7800 on stock volts and default power target. Hasn't shut down a single time. My first card is under my GPU+CPU loop, second is running on air. I'd guess all my cooling components, pump etc. are adding some wattage to that 800W~ estimation as well. I must be really pushing the PSU at times haha.
I had a 1000W seasonic platinum that would get shutdowns in TW3 as well. I was drawing near 1kw at the wall which still leaves a little head room, but my shutdown issue was due to surge protection option in bios causing early trip. Turned it off and never had another shutdown, but bought a 1200w just to be safe.
Damn I really am not going to buy a new 1000W+ unit. I just experienced a shutdown mid-mission in The Division, guess it's back to tweaking the BIOS'.
Yah they get expensive above 800-850W.. probably better off just to lower your overclocks a bit. The difference in performance is likely hardly noticeable. Yah you might lose a few points in benchmarks but playing in games a few fps less would be hard to spot. Dunno what voltage your CPU is at.. but I know when I was testing my i7-6700K I had to really ramp up voltage a ton going beyond 4.6Ghz. I settled on 4.7Ghz @ 1.315v. It was 1.28v @ 4.6Ghz, I don't remember what was stable for me at 4.8Ghz or 4.9Ghz but I remember voltage was a ton higher and temps too. I even got it too boot at 5Ghz but it would BSOD or hard lock if I tried to benchmark it. Scaling back a few O/C will get you within that power envelope to avoid unexpected shutdowns.
Well if I run both GPUs at the absolute stock BIOS with no adjustments whatsoever, then the PC won't shut down randomly. At least it didn't at the time but the GPU setup was a bit different then (current second card was as my primary, heat issues with that STRIX card restricting boost clocks etc.) and the GPUs only boosted to 1190 As for the CPU, it's at 1.36 volts now. I'm seriously starting to think I should just pull out the second card and overclock the first card back to 1600~ as it used to be and leave it as so. This STRIX card has been a pain in the ass ever since I got it, Agent-A01 knows
Personally I wouldn't be running like that. A power surge from the PSU if it fails could be more expensive than buying a new PSU. So I agree, for now, take out the other one.
Yeah I'm going to see if I can tweak the cards to something like 1.11ish volts with a 275W power target and achieve a sub 1300MHz core clock. If not, I'm going to pull out the other card. EDIT: OK, I just made a BIOS for both cards. 1.112 core voltage, 275W PT and 1300/8000 clocks. Now the PSU fan doesn't kick in as aggressively as it used to and the BIOS/clocks seem to run fine. I'm going to test further for any issues. How much would an adjustment like this drop the wattage stress on the PSU? PS. Secondary card, Strix 980Ti, still hits approx 80c under load (TW3 4K) even though I've slapped 2 Corsair AF120s on it :3eyes:
Putting what your system is currently clocked at and all the components in your PC through this calculator (assuming you have your cpu 4.8ghz @ 1.36v and GPU's at the above) your load wattage would be around 853w and they recommend a 900w PSU. My system for comparison is around 450w load with a 500w recommended PSU. Of course, a watt meter will be more accurate but at least its a rough estimate.
Yeah but I've read many saying those PSU calculator sites aren't really accurate and don't even give a rough estimate, more like used-ish power +100W. Anyhow, I'm quite on the edge with this PSU, hopefully not too much though.
So, in conclusion I've now ordered an EVGA GeForce GTX 1080 SC Gaming ACX 3.0 which should arrive in a couple of days, it will go under custom my loop and get clocked straight away. Yes I know, depending on one's POV, it's a rather huge downgrade from SLI'd 980Ti's but it'll suffice well for my needs and there's no way I'm going to pay 900e for a Ti, just nope. I've also put my Strix 980Ti on sale. The Inno3D 980Ti I will either sell or exchange with my brother's Strix 970 which would then end up for sale as well. In the end I'm just gonna have to pay, depending on the case, approx nothing or about 180e for the 1080 - not so bad considering I'm going to have a great single card and I'm not going to have to put up with the heat and other issues two 980Ti's brought to the table.
