Weird GPU behavior

sylak2_09896ed591

Hi Guys

I have been rendering using IRAY for almost 2 years.

For my earlier projects I was only rendering to 1280 x 720. 

I have a 980Ti, 780TI and a 750 GPU in my system.

With all of my earlier renders they tend to reder fairly fast and consistant.

Recently I have been starting to render in 1920x 1080.

For the most part it was working well obviously taking longer to do a render but it would render well.

Recently when I do a render the render would be going great for a while then wihtout even getting to 1% it would grind to a hal.

I thought maybe VRAM, Then RAM etc, etc.

I could not work it out.

So I got a new monitoring program to see what was actually going on and here is where I hit a very strange thing.

When I start the render all 3 cards are working great the 980TI was only using 1.2gb of it's 6GB VRAM, the 780ti is only using 1.6 of its Vram, The 750 was using 1.3 of its Vram.

They are all using most of their Core clock and Memory clocks.

So rendering well and working as they should.

But then the Render grinds to a halt and I notice the 980Ti and the 750 are not using any of their Core Clocks or Memory clocks. So they decide to stop offering their power.

Meanwhile the 780TI is still going at full speed.

Does anyone know why this is happening?

It has turned my usually good render rig into a render pig.

This has been incredibly Frustrating.

I don't get it.

Thanks For you help in advanced.

Cheers

Sy

 

 

JamesJAB

You could try checking your log file and see if there is anything in there around the itteration where the 2 cards drop off of the render.

ricswika

I have a similar problem running 3 GTX 580s. I was able to get my renders to complete by devoting one GPU for display and the other 2 for rendering. As a test, maybe turn off one of the GPUs and see if that helps.With my system, it seems to need one GPU for display so you can't use all three for rendering, even though I did that with version 4.8.

sylak2_09896ed591

Thanks for the response guys.

Yeah I tried that as well

I had the 750 just working as disaply and not rendering but it did not change the outcome.

I also tried dropping the display from the 980 so it was not plugged in to any monitor but same result.

I also stated getting regualr crashes.

I found that once I pulled the 750 out they started to work better I still get the occasion where the 980 drops but the 780 seems to keep working no matter what.

Usually the solution to that now is to shutdown Daz clear it out of task manager then restart then it will run for a few renders again for a ahile but eventually the 980 will stop working again.

It is strange and annoying but I think the reason for the improvement was the PSU I have. I think it just was not powerful enough to run 3 cards.

It may still be the problem but it is an 800W PSU which should be enough to run two cards fine.

Any other thoughts.

Thanks guys

Cheers

Sy

 

JamesJAB

If it worked fine for a while, and just started acting up.... It might be that your PSU is wearing out.
The 780ti and 980ti are each rated to use 250W.  Under full load while rendering they may be using a little more.
Your 750 depending on which one it is.. (normal or ti) is rated to use either 55 or 60W
Depending on what CPU yoou are running, that could be rated anywhere from 60 - 140W
Without even adding any other hardware (Motherboard, RAM, HDD, DVD, Cooling Fans, Wifi, Keyboard/Mouse, LED lighting)...
Your big 4 devices (3x GPU, 1X CPU) are drawing somewhere in the range of 615 - 700W
Power Supplies are not rated to operate at their peak output for extended periods (like what is demanded of them while rendering).

You should probably think about investing in a new "Name Brand" PSU that is at least 1000W

sylak2_09896ed591

JamesJAB said:

If it worked fine for a while, and just started acting up.... It might be that your PSU is wearing out.
The 780ti and 980ti are each rated to use 250W.  Under full load while rendering they may be using a little more.
Your 750 depending on which one it is.. (normal or ti) is rated to use either 55 or 60W
Depending on what CPU yoou are running, that could be rated anywhere from 60 - 140W
Without even adding any other hardware (Motherboard, RAM, HDD, DVD, Cooling Fans, Wifi, Keyboard/Mouse, LED lighting)...
Your big 4 devices (3x GPU, 1X CPU) are drawing somewhere in the range of 615 - 700W
Power Supplies are not rated to operate at their peak output for extended periods (like what is demanded of them while rendering).

You should probably think about investing in a new "Name Brand" PSU that is at least 1000W

I will look into it but the PSU is a Namebrand and a very good supply.

It is an Antec 850 Continuous Power PSU.

So it is not a cheapy.

Cheers

Sy