having reboot issue when rendering

[aeolian001]

I have three GTX 780 TI's and a 1400 watt PSU. I can render with any two of my GPU'S, but as soon as I set octane to render with all 3 GPU'S, computer immediately restarts "which rules out heat related issues". does this sound like a PSU issue or can anyone suggest some tests I can run?

thanks

[mib2berlin]

Hi, 1400 Watt should be enough for 3 780Ti and immediately restart meant it can´t be overheating of the cards.
Hm, you could try Priority Settings in Preferences > Devices.
Check Priority for all cards and set to Low Render Priority in the GUI.
You loose 10-15 % performance but cards also need less power and your PS does not deliver 1400 Watt.
If this work you can downclock your cards to save some power.
I read in another forum user had problems with Cuda render engine Cycles and latest Nvidia driver.

http://blenderartists.org/forum/showthr ... uch-Cycles

Cheers, mib

[smicha]

If this is not a blue screen restart but a regular restart - power goes off - then it might power supply issue (not wattage - 1400W is enough for 4x 780). Check all your cables connections, try to swap PSU cables for 3rd gpu. BTW what are your 780s? Reference ones?

[aeolian001]

I have tested all GPUs in all slots, they all run just fine while rendering. its is only when I have all three rendering at the same time that my computer will just reboot. there is no blue screen, no freeze, just like it was powered off and restarts. I get the message, windows did not shut down correctly and an option to choose safe mode or start windows normal mode. This was not an issue until recently, all GPU's would render just fine before, this just started.. I guess i'm trying determine what to replace first. PSU will be a pain but may be necessary. Is it possible this could be processor, ram, motherboard? or more than likely the PSU? I am using computer now, just using internet with no problems, if i render with only 2 GPUS, doesnt matter which two, no issues. soon as i set octane to render with all 3, within seconds i get a restart.

thank you btw for the feed back, as for the priority option, I will try that, maybe will be a temp fix. I haven't installed any new video drivers, so that would not be an issue.
I will check my cables and make sure they are all secure. my cards, two are MSI OC 780 TI, one is an ASUS OC 780 TI
but I do need to resolve this problem as I have an unstable computer and is not good for business.
I ordered a new PSU:
Seasonic SS-1250XM X-Series ATX PC Power Supply
http://www.amazon.com/gp/product/B00607JLWU

hoping this will fix the problem, just worried as I have projects with deadlines and i'm trying to cover all my bases,

[smicha]

Have you tried to switch cables between gpus? Are you using any cable extensions? What is your motherboard?

[aeolian001]

not using cable extensions, mother board is p8p67 WS Revolution, processor I7-2600k

[smicha]

Do you have a molex connected to mobo? I have exactly same setup look at my footer. Do you have your CPU oc at constant voltage?

[aeolian001]

I'm not sure about a molex connected to board, need to check.. that is the white connector with 4 holes i am assuming. I do think its possible it could be an overclock issue, i bought this board with the processor and ram already setup with an overclock. i am just not that experianced inn over clocking. i know how to get into bios and click on advanced. then i see the AI tweaker. there are the options for the OC settings. how do I check to see or what part of bios to confirm if it is constant voltage? I am pretty sure i set most everything to auto.

also, i noticed by unchecking "use priority settings" for GPUS in octane. it does not crash while rendering all 3. at least so far that is

[aeolian001]

also, i noticed by having "priority settings unchecked" for GPUs seems to render a second or 2 faster.. is that normal?

[aeolian001]

seems setting bios to higher power settings, and unchecking priority settings for each GPU in octane solved my issues.. thank for the help!