Poor performance out of a kick ass system

[Peter Berg]

Hi Rob,

Do you know anything about the PCI-E slot configuration on the Asus P9X79-WS board? In the manual they are not clear if some of the lanes are shared or not. I have the 2 Nvidia cards (both need 16x (I think)), a RED Rocket (needs 8x), and a decklink (needs 1x)card to fit in there and just curious how the PCI-E lanes are distributed.

I had put them in based on my own logic but performance was not good. I went back to the config guide (at least as close as I could get it since the board is slightly different) and performance improved. Just wanted to know for myself how the lanes are distributed and what the best install might be for the WS board.

thanks,
Peter

[Pepijn Klijs]

From what I read on the asus site, you cannot fit all those cards and have them running at their max bandwidth. It says: 4 x PCIe 3.0/2.0 x16 (dual x16 or x16/x8/x8 or quad x8, black+blue)

So I guess that means that when you plug more then 2 cards, only one card will get the 16 lanes and the other two 8.

Editor/Colorist, Amsterdam, The Netherlands
http://www.pepijnklijs.nl

[Robert Houllahan]

Weird, CUDA driver on Win7 issue? Maybe run a 9800GT as GUI instead of the Quadro?

I have not yet run Resolve on Windows but I am building another Asus P6T7WS system with GTX-480’s for GPU and a 9800GT for GUI which I intend to dual boot Win7 and Lion.

Oh Windoze…

-Rob-

Robert Houllahan
Director / Colorist
Cinelab Inc.
http://www.cinelab.com

MAHC-PRO 6-Core 3X GTX285 20Tb SAS Wave Panel Panny 11UK SDI Plasma. Light-Space CMS + Hubble

[Peter Berg]

Thanks Pepijn,

I am still a bit confused about the PCIe lane configuration. I contacted Asus but they were not nearly as knowledgeable as I thought they should be.

I agree that the spec for the P9X79-WS says:
4 x PCIe 3.0/2.0 x16 (dual x16 or x16/x8/x8 or quad x8, black+blue)

So reading that it does seem that one of the graphics cards will only be running at x8 (hopefully the GUI card and not the GPU card).

But looking at the specs for the P9X79-PRO it says this:
3 x PCIe 3.0/2.0 x16 (dual x16 or x16, x8, x8)
1 x PCIe 3.0/2.0 x16 (x8 mode)

Does this mean that on the PRO board I can run my 2 Nvidia cards at x16 in the first set of PCIe slots and I could still run the RED Rocket at full x8 speed in the other PCIe slot? It almost seems like the PRO board has more independent lanes (32 lanes and 8 lanes) vs the WS which has more shared lanes (32 lanes and 2 additional x4 slots).

Can anyone clarify here?

thanks!
-Peter

[Pepijn Klijs]

Hi Peter,

I think your understanding is right, at least, that’s how I would interprete it as well. But Asus should be able to give you a real answer.

What is also a good question is how big the performance change is when using 8 lanes instead of 16. I think I once read that it wasn’t such a big deal, but I’m definitely not shure.

Editor/Colorist, Amsterdam, The Netherlands
http://www.pepijnklijs.nl

[Peter Berg]

Hi,

I wish I could say how much this might be hurting my performance overall. It seems that I can get the GUI card to run at x8 and the performance is much better than when the GPU card is running at x8 (obvious I guess).

So I also tested my thory. And with the Rocket out of the system, both Nvidia cards run at x16. With it back in (in either of the remaining x8 slots) one of the Nvidia cards drops down to x8.

Dissapointing. Asus is not able to give me a clear awnswer. I don’t even think some of their support people know what PCIe means.

I’m not sure if I can return this WS board and try to the PRO board. I wish I could though so I can see if it gives me better performance. Even the ‘regular’ P9X79 looks like it might have better PCIe performance than the WS (at least in my specfic case).

So I would warn users to possibly not buy the WS version. Even though you have all x16 physical slots, you will be limited by the way the board shares the lanes among the cards.

Suddenly the Mac Pro doesn’t look as bad performance wise as I thought it was.

-Peter

[Rohit Gupta]

With the Pro, you should be able to run what you want. I think it’s listed in our configuration guide.

Also V9 has support to get better performance with a single GUI/CUDA card so that might free up a full speed slot as well.

[Sascha Haber]

The Mac Pro is a kickass system, period.
None of that Winblows hassle, great people doing modified cards for it and if you really need power, you get a proper Cubix 8X and put 3 GTX 580s in.
The time I wasted on fiddling that GlobalStor I could have spent on working and buying a proper Mac.

By the way…that whole lane talk made me think that maybe the raid cards could slow it down.

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

[Peter Berg]

Thanks Rohit,

So I bought a P9X79 PRO board and did more testing. So I can confirm that all the PCIe cards run at their full speed. The 2 Nvidia cards run at 16x and the RED Rocket is running at X8.

The reason I went with the WS is that some of the COW members had theorized that the WS board would be a better choice since it had more PCIe x16 slots. But I can confirm that the WS board has less independent PCIe lanes than the PRO (or maybe even the regular P9X79). I think this is strange and not at all what I would expect.

So at this point I do not see any reason to choose the WS board and in fact the WS does not run as well as the PRO board.

I don’t really see much performance difference between the two boards, but since the WS board costs more and runs the PCIe cards at a slower speed, I think it would be a mistake to choose the WS board (hopefully I can save someone else from making this same mistake).

Maybe someone can point out some other advantage to the WS board but I’m not seeing it at this point. Now I have to find a way to sell the WS.

And just a heads up.. Windows machines are a major pain to setup. Make sure you have a few weeks of free time to work your way through all the issues. (if you are building your own system)

-Peter

[Jonathon Lee]

Actually, I’ve had great experience with an HP Z400…. 3.06gHz 4-core, 24GB, Q600 GUI, GTX285 GPU, LSI-SAS RAID PCI-e, DeckLink Pro HD, Win7 64…. also run Media Composer and some DCP apps on it. Good performance for HD res and SUPER easy to setup. Worked right out of the gate. Seriously, just as easy to setup as my Mac system… and I have a Dell 24in multi-touch monitor that’s pretty cool.. direct support in Win7. The system was less expensive then going DIY. The HP “Z” systems are the way to go IMO, if you need Win.

– Jonathon