Real time playback issue (2xQ4000+GT120+MacPro4,1)

DaVinci Resolve

Real time playback issue (2xQ4000+GT120+MacPro4,1)

Posted by John Pilgrim on May 30, 2012 at 10:23 pm

Hi all,

I have a playback speed issue.

The only way I can get 24fps playback is to switch the video monitoring to 8-bit on the Config page.
(Thanks Rohit for brining this up over at https://forums.creativecow.net/thread/277/15755)

If I set the video monitoring to 10-bit, even with no grades, I never get realtime 24fps playback, usually around 19-23fps.

I’d really like to monitor at 10-bit.

What gives?
Is the GT120 not up to snuff?
Does the GT120 dislike being in x4 speed slot #4 rather than x16 speed slots #1 and #2?

Thoughts?

Thanks,
John

All the details:

Much of my media is 1080P24 ProResHQ (≈200mbit/sec), XDCAM EX (35mbit/sec) or XDCAM HD (220mbit/sec)
During playback, my CPU stays around 80% idle.
My RAM remains 75% free (9.35GB free of 12GB).
My media drives clock in around 200-250MB/sec according to BMD Disk Speed Test.

Resolve 8.2 full version
Mac OS X 10.6.8
MacPro4,1 8-core 2.26GHz, 12GB RAM
Slot 1: Quadro 4000 Mac headless
Slot 2: Quadro 4000 Mac headless
Slot 3: Decklink Extreme 3D
Slot 4: GT120 for GUI
Internal 1TB Boot drive
Internal 2TB 2-drive RAID-0 (BMD Disk Speed Test says 212MB/s write and 205MB/s read)
Internal 120GB Corsair Vertex3 SSD (BMD Disk Speed Test says 204MB/s write and 265MB/s read)

Standard Candle 8.2 results using 10-bit monitoring:
V1 2 nodes : 23.0-24.0 fps (fluctuates)
V2 4 nodes : 22.5 fps
V3 6 nodes : 22.0-24.0 fps (fluctuates)
V4 12 nodes : 13.0 fps
V5 NR 4 : 24.0 fps
V6 NR 3 : 21.5 fps
V7 NR 2 : 11.0 fps
V8 NR 1 : 3.0 fps

Standard Candle 8.2 results using 8-bit monitoring:
V1 2 nodes : 24.0 fps
V2 4 nodes : 24.0 fps
V3 6 nodes : 23.0-24.0 fps (fluctuates)
V4 12 nodes : 13.0 fps
V5 NR 4 : 24.0 fps
V6 NR 3 : 21.5 fps
V7 NR 2 : 11.0 fps
V8 NR 1 : 3.0 fps

FWIW, if I replace the original 00003802.mov with an upresed 1920×1080 10butUnc MOV of the same file, using 10-bit monitoring, I get:
V1 2 nodes : 19 fps
V2 4 nodes : 19 fps
V3 6 nodes : 18 fps
V4 12 nodes : 13 fps
V5 NR 4 : 21 fps
V6 NR 3 : 19 fps
V7 NR 2 : 11 fps
V8 NR 1 : 3 fps

(Sidenote: If I’d get a performance boost, I’d consider ditching the GT120 and one of the Quadro4000’s and putting in a GTX580 and using the remaining Q4000 for GUI, but I don’t think my power supply would like me. TDP would increase by another 50 watts.)

John Pilgrim replied 14 years, 2 months ago 5 Members · 10 Replies
10 Replies

Dwaine Maggart
May 30, 2012 at 11:00 pm

It’s very important that the GPU AND GUI cards are in x16 PCIe slots. Your problem is likely because you have the GUI card in Slot 4, which is a x4 slot.

To answer the next question, no, you can’t put multiple GPU cards in the Mac chassis. You must use a PCIe expansion chassis if you wish to have multiple GPU cards.

Dwaine Maggart
Blackmagic Design DaVinci Support
John Pilgrim
May 30, 2012 at 11:33 pm

Well then I’m really glad 2xQ4000+GT120 works as well as it does!!
Dwaine Maggart
May 30, 2012 at 11:35 pm

I suspect that if you remove one of the 4000 cards and move the GT120 into that slot, you will have better performance.

Dwaine Maggart
Blackmagic Design DaVinci Support
John Pilgrim
May 31, 2012 at 1:13 am

GT120 + Q4000 cuts my GPU power in half in order to regain in-spec GUI. An interesting trade off.

If I went Slot1 Q4000 GUI and Slot2 Q4000 GPU, will Resolve use any of the GUI Q4000 for GPU processing (in addition to the dedicated GPU Q4000) or will it only use the dedicated GPU Q4000?
Juan Salvo
May 31, 2012 at 2:46 am

Get the 580. A single 580 will out perform two q4000s!

Online Editor | Colorist | Post Super | VFX Artist | BD Author

https://JuanSalvo.com
Sascha Haber
May 31, 2012 at 7:03 am

Keep one Q4000 as you main card and get a GTX 470 which runs perfectly fine alongside and is almost three times as fast as one single Q4000

A slice of color…

DaVinci 8.2.1 OSX 10.7.2
MacPro 5.1 2×2,4 24GB
RAID0 8TB
GTX 470 / Quadro 4000
Extreme 3D+

ICA Instructor
https://www.icolorist.com/Sascha.html
Dwaine Maggart
May 31, 2012 at 6:23 pm

If you use 2 Q4000 cards, the one used as the GUI card will not provide any GPU processing.

Dwaine Maggart
Blackmagic Design DaVinci Support
Sascha Haber
May 31, 2012 at 6:32 pm

It will make the computer usable.
Which its not really with a GT120.
I have more needs than just Resolve (Smoke, Scratch,Diablo3 😉 ..and as primary card the Q4000 is excellent..as GPU card a joke.

A slice of color…

DaVinci 8.2.1 OSX 10.7.2
MacPro 5.1 2×2,4 24GB
RAID0 8TB
GTX 470 / Quadro 4000
Extreme 3D+

ICA Instructor
https://www.icolorist.com/Sascha.html
Colin Travers
June 1, 2012 at 11:34 pm

I am actually now curious if i could replace my 120 with a 4000 or would the power drain be too much on the system based on my specs listed below?

DaVinci 8.2.1
OSX 10.7.4 (SSD in optical bay)
MacPro 12-core 5,1 2.66 32GB
RAID0 8TB
GT120/GTX580 (CUDA 4.2.7)
Extreme3D
FSI LM-2461W / Panny VT25
Tangent Wave / Wacom
John Pilgrim
June 2, 2012 at 12:14 am

[Colin Travers] “I am actually now curious if i could replace my 120 with a 4000 or would the power drain be too much on the system based on my specs listed below?”

GT120 50 watts TDP Quadro 4000 142 watts TDP GTX580 244 watts TDP
So going to a Q4000 you’d be increasing your max power consumption by 92 watts.

FWIW, the MacPro power supply (661-5449) is rated at 980 watts.

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