[Blase Theodore]

I think you’re probably right, but I hate hardware mysteries.

Here are some numbers..

The 2k data is probably around 3Gb/s (think dual link HD-SDI). And stereo 2k should be about 6Gb/s. But a 4k stream should be around 4x that. Lets say 12Gb/s. And then stereo 4k would be 24Gb/s.

A single PCI 2.x16 slot should provide 16Gb/s upstream and 16Gb/s downstream. So the data flow might be..

2k RED:
system -> 0.1Gb/s -> Redrocket
RR decode – > 3Gb/s -> system
system – > 3gb/s -> Dual GPU’s
GPU’s -> 3Gb/s -> system

Total upsteam/s: 3 of 16Gb
Total downstream/s: 6 of 16Gb
fine

Stereo 2k RED:
system -> 0.1Gb/s -> Redrocket
RR decode – > 6Gb/s -> system
system – > 6gb/s -> Dual GPU’s
GPU’s -> 6Gb/s -> system

Total upsteam/s: 6 of 16Gb
Total downstream/s: 12 of 16Gb
fine

4k RED:in 2k timeline
system -> 0.1Gb/s -> Redrocket
RR decode – > 12Gb/s -> system
system – > 3gb/s -> Dual GPU’s
GPU’s -> 3Gb/s -> system

Total upsteam/s: 12 of 16Gb
Total downstream/s: 6 of 16Gb
fine

4k RED:
system -> 0.1Gb/s -> Redrocket
RR decode – > 12Gb/s -> system
system – > 12gb/s -> Dual GPU’s
GPU’s -> 12Gb/s -> system

Total upsteam/s: 12 of 16Gb
Total downstream/s: 24 of 16Gb
problem

stereo 4k RED:
system -> 0.1Gb/s -> Redrocket
RR decode – > 24Gb/s -> system
system – > 24gb/s -> Dual GPU’s
GPU’s -> 24Gb/s -> system

Total upsteam/s: 24 of 16Gb
Total downstream/s: 48 of 16Gb
problem

Again, I recognize that this is already being successfully used, but everyone seems to be happy to glaze over the details, which will be important as soon as we get into 4k. At which point I might regret not having bought dual cubix instead of one x4.

[Blase Theodore]

[Illya Laney] “Accelware and Octane Render are not render farms.”

Yes, they are. They are computational and physics-based render engines respecitvely.
https://www.refractivesoftware.com/

[Illya Laney] “Most of DaVinci’s load is on the GPU’s and like Eric Fiegehen from Cubix said “PCIe bus traffic is minimal.””

Eric was referring to Accelware and Octane Render in that statement, which again is the opposite of what we’re doing.

• With a render engine like Octane, the CPU is passing a few lines of code through the PCIe bus to the graphics card, which in turn does massive calcuations on a small volume of data.
• A ProTools rig takes a tiny audio sample, probably a few Kb, and runs it through powerful DSP’s.
• Resolve on the other hand has to deal with an uncompressed 4k image buffer cycling 24 times a second.

This is not an “apples for apples” comparison.

I’m not saying it won’t work, but I am saying its a legitimate question, and glazing over it does no one any good.

Robbie’s going to test it next week, which is as definitive an answer as I could ask for.
It will answer both the 4k and R3d concern at the same time.

[Blase Theodore]

Cool this is great to hear!

My concern would be that you won’t hit a bottleneck until you actually load an r3D job, and the RR card starts to compete with the other 2 cards. Have you tested that yet?

[Blase Theodore]

[Illya Laney] “Why would you add a RAID card and DeckLink when you could throw 3 GTX 285’s in there? Just keep the RAID and DeckLink in the suggested slots on the MacPro.”

Because that has never actually been tested by anyone to work. Thats my point.
Also because I ABSOLUTELY need a redrocket card working in the system. And for any 4k work, I’d need 2.

[Illya Laney] “From an old post by Eric Fiegehen
“While the argument regarding bus traffic is certainly valid for some applications, Cubix has found that other applications from vendors such as Acceleware and Refractive software (Octane Render) execute mainly on the GPUs, not on the CPUs. Therefore, PCIe bus traffic is minimal and does not impact performance in most cases.”

Again you are not understanding the problem. In a render farm like referenced above, the CUBIX is ideal. Because processing is heavy and data bandwidth is minimal. We are the EXACT OPPOSITE of render farms, or computers simulations, or ProTools rigs. We are processing light and bandwidth HEAVY!

Cubix x2 seems to work fine for 2k. But assuming cubix x2 would not bottleneck on 4k, or that cubix x4 would not bottleneck in 2k or 4k, is still an untested assumption.

[Blase Theodore]

I called Cubix today..

I voiced my concern, that the x4 unit would essentially be splitting up a single x16 bus 4 ways. They explained that basically each device would have the full x16 bandwidth, but would only have access to it for 1/4th of the time.
So while the device itself does NOT in anyway create a bottleneck, the x16 slot on the motherboard does.

Whether the bottleneck is significant or where returns becoming diminishing is yet to be tested.
Evidently they are shipping an x4 unit out to BM for testing right now, so the answers are coming.

THE PROBLEM:
As I understand it, the layout suggested in the BM config guide is using an x4, but to my knowledge, BM has only tested this with dual x2 units.

The issues I’m bringing up wouldn’t be a problem with the x2, but could be with the x4. And the layout I’d want could only be done with an x4 (or an x4 and x2).
it would be:
– GT120
– cubix ->
. GTX285
. GTX285
. Red rocket
. Red rocket (negotiable, but icing on cake)
– DL Extreme 3d
– RAID card

And ideally I’d want to know how it handles at 4k as well.

[Blase Theodore]

I’ll be honest, it still seems a bit vague.

You’re simply saying that the cards aren’t drawing a whole lot of bandwidth, so they can all coexist without saturating a single PCIe2x16 slot.

If this were a dynamics engine or something, that would make sense. The processing would be the biggest factor and the data bandwidth itself would be minimal. But we’re talking about 4k video processing. Its probably the most bandwidth intensive field there is.

Here’s a great explanation of my problem: Put a gtx285 in an x4 slot and try and run Resolve. It would run like crap. Conceptually that’s what you’re doing. Turning an x16 slot into 4 x4 slots with 4 graphics cards (or two x8 cards)?

If I’m missing something please help me see where.

Or rather if its too complicated to explain, please help me understand the consequences.
ie. –

• Will a cubix box help add more realtime nodes for 2k but hinder 4k?
• Will adding a redrocket to a cubix box (that already has dual gtx285’s) be slower than adding it to the main board?
• Would there be diminishing results using 3 or 4 gtx285 cards as opposed to just 2?

Thanks,
Blase

[Blase Theodore]

Thanks John,

On your advice, I newegg’d the ATTO R380 card to replace the RRaid, which I plan to beat with an aluminum bat.

Much appreciated!

-Blase

[Blase Theodore]

Happy New Years to you too Darin.

[Blase Theodore]

I’m in exact same situation.
I ignored the many warnings I was hearing about using this card, and bought it anyway. Mine died about a month in and has the same issues.

[Blase Theodore]

Please someone correct me if I’m wrong..

As I understand Prores444 exists as both a natively RGB codec and a natively YUV codec. Basically its a wrapper for 2 different sub-codecs in different color spaces wrapped in a mysterious black box.

I’m not really sure who thought that would be a good idea, but I refuse to work with the format for the time being. I’m not convinced that anything other than direct apple products understand the codec well enough to avoid treating it incorrectly as YUV or RGB.

If someone has a better way of understanding this than trial and error, I’d welcome the insight.