GPU Issue, supposedly

[Frequent_Flyer 1]

Hello,

I have posted about a similar topic before, but this is a little different.  First and foremost, here are my specs:

Case: Cooler Master COSMOS II RC-1200-KKN1

Motherboard: ASRock Z270 SuperCarrier LGA 1151

Power Supply: ENERMAX ERV1000EWT-G 1000W

Memory: G.SKILL TridentZ Series 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 2800 (PC4 22400) (Quantity: 2)

Video Cards: EVGA GeForce GTX 1080 SC GAMING ACX 3.0 (Quantity: 4)

Processor: Intel Core i7-7700 Kaby Lake Quad-Core 3.6 GHz

Disk Drives: Samsung 850 PRO 2.5" 1 TB SATA III Vertical Internal SSD (Quantity: 2)

DVD Drive: Intel Black SATA Slim DVD drive

Other: ICY DOCK ToughArmor MB994IPO-3SB Hot Swap Mobile Rack Backplane Cage Module

Other: ICY DOCK MB994TK-B EZ Slide Mini Tray Drive Tray with Metal Lock for ToughArmor MB991/MB994 series

 

I was told by someone from Lockheed Martin to determine if my low FPS was due to my CPU or GPU.  Here is what he said:

"One quick test for CPU/GPU boundedness is to shrink windows down to smaller sizes.  This typically will improve FPS if you are GPU bound and won't affect it too much if you are CPU bound." I tested out the suggestion to determine CPU/GPU boundedness by shrinking window sizes and see how it affected performance.  My results showed that by shrinking 6 undocked views and placing them on the same display, the FPS was increased from 22 to 43.  My 7th view took up another display and was a Cockpit view.  How could it be a GPU problem with how many GPU's we have.  They are not SLI'd and each graphics card runs its own projector for a display.  Previously, I was told that the CPU wasn't able to handle everything, and that the GPU's were giving the CPU more work to do.  However, through the recommended test I am confused at how the GPU is the problem then.  Any thoughts or comments would be appreciated.

 

Thanks.

 

[BrettT 63]

You don't mention the resolution that your PC is driving (1080, 4k?).  It sounds like from your post that each card is driving two displays and the 7th display is driven by the 4th card?

One thought is the power supply may be your limiting factor and could possibly be limiting the performance of your video cards. When you are reducing it to 2 cards you back off the power quite a bit.  Yes it is 1000W but putting your specs into a power supply calculator and it has your setup needing almost 1100W to power the Video Cards at Boost Clock

[Bob Scott 7,716]

You might ask Pete Dowson how he does his...I think he runs a triple-GPU triple-projector setup on a single PC for his exterior displays.

Regards

 

 

[Frequent_Flyer 1]

23 hours ago, BrettT said:

You don't mention the resolution that your PC is driving (1080, 4k?).  It sounds like from your post that each card is driving two displays and the 7th display is driven by the 4th card?

One thought is the power supply may be your limiting factor and could possibly be limiting the performance of your video cards. When you are reducing it to 2 cards you back off the power quite a bit.  Yes it is 1000W but putting your specs into a power supply calculator and it has your setup needing almost 1100W to power the Video Cards at Boost Clock

Here is what each GTX 1080 is powering, sparing no detail (not 4k unless specified):

Graphics Card 1: 

1920x1200 Projector

1920x1080 Monitor

1080x1920 Monitor

Graphics Card 2:

1920x1080 4k TV

1920x1200 projector

1920x1080 monitor

Graphics Card 3:

TWO 1920x1200 projectors

1080x1920 monitor

Graphics Card 4:

1920x1080 monitor

1920x1080 Touchscreen Display for my HDD

[Frequent_Flyer 1]

Just now, Frequent_Flyer said:

Graphics Card 3:

TWO 1920x1200 projectors

1080x1920 monitor

*****

Graphics Card 3:

TWO 1920x1200 projectors

1080x1920 Projector

*****

[BrettT 63]

That is a decent amount of pixels you are pushing, depending upon the settings.   I am not an expert but I would say being GPU limited is probably a good place to start

1) Your Motherboard says it supports 4x 8 PCI configuration but the Z270 chipset  only has 24 PCI lanes....so you might be getting a situation where your GPUs are dividing up the PCI lanes as 8/8/4/4

2) You performance increases a good bit once everything is put on one screen

3) Possibly power limited too.  Might be worth using GPU-Z to see if your Video Cards are being throttled due to voltage or other GPU limitations

BTW....sounds like quite the system you have there!

 

Just curious....you invested in 4 1080 GTX cards and other high end components....why go with the locked version of the 7700 chip instead of the 7700K?

[lownslo 592]

Wow, Brett!!!  Great observations and great questions!  Good on ya!

Regards,

Greg

[Frequent_Flyer 1]

Hey Brett,

 

Thanks for the reply.  I will check into what you are saying.  I am confused what point you were trying to make with your second comment though, if you could clarify.  In regards to why the 7700 and not the 7700K.....it isn't my system unfortunately, so I didn't get to choose what goes into it.

 

Thanks for the help!

[BrettT 63]

No problem!

My second point was that the performance increased two fold when you put all the windows on the single monitor.  I believe this would take a large burden off of the GPU (basically driving 1 display instead of 3).  It would also take a burden off of the PCI lanes as you would basically only be using one GPU.  Likewise it would also take a burden off of the power supply as only one (possibly two) of the GPUs would be in a high performance mode and thus drawing a lot of power.  Just clarifying my thoughts.

 

Good luck!

[Frequent_Flyer 1]

Thanks for the clarification!