Hardware advice for 8 x SDI out

I’m sure there may have been a similar question in the old forums but just wanted to check for thoughts regarding a new hardware build.

I’m looking at a system to support 8 x SDI out, simply outputting channel backup slates so it would be either still images with a looped audio bed or looped ~1 minute video segments.

The hardware I’m looking at is:

  • 2 x Blackmagic Duo2 Cards configured as 4 out on each at 1080i50
  • Quadro K2200 Graphics card
  • Windows 10 Pro (have only used 7 up until now…)
  • i7-7700 3.6GHz processor
  • 8 GB RAM
  • 500Gb SSD

Would appreciate any thoughts people might have on whether this will work out?

I have no experiance with 8 channels, But I had built a system with 4 channels with similar system specs and it was not able to handle all 4 channels at the same time. So I would use a stonger system, probably a Xeon processor, a lot more RAM and at least a RAID 0 of SSD’s. Or go with multiple weaker systems with 2 to 4 channels each. But as I said, not really experianced…

Hi I have an system with these specs:

  • Decklink Quad 2
  • Intel Core i7 5390K
  • Nvidia Quadro P2000
  • Raid 0 with 6x Samsung 850 Pro 256GB (Media)
  • 1x Samsung M.2 128GB (System)
  • 4x 16GB DDR4-2400 RAM

Playing out all 8 Ch results in an still bored machine :wink:
Your config looks good so far, but I also would suggest more RAM and an Raid 0 of two SSDs.

Thanks both, slightly conflicting opinions :slight_smile:

@didikunz I’m guessing, only based on seeing you mention some of the things you do with Caspar on the old forums, that the system you are talking about was doing multiple layers and/or keying for graphics work?

@TheYouth Many thanks, will bump the RAM and add a second SSD, may I ask what sort of thing you are playing out (graphics or video etc) and what sort of RAM utilisation you have on that machine.

I’ve only gone with the Duo’s so there are regular BNC’s, the price is much the same and I wasn’t sure about the support for the Quad2 as an 8 channel output with Caspar but may change that.

Depends on the job. :wink: For me it´s an universal tool. Some days it just plays video, other days it plays only graphics. Some days it does both on different channels… so very hard to tell you the RAM utilisation cause it depends on the Codecs used in the video files and how sophisticated your graphics are.

… and an other days it fires of two 12 projectors with it´s three P2000 cards in it :wink:

Hi Duncan, the system is used also for recording and a single channel of recording in 1080i50 makes a lot of noise :smile: but it has harddiscs and not SSDs (because it need to record and play for hours). So that can be the problem. As I said, I am not an expert on these use cases.

By the way, I would also prefer 2x Duo 2 over Quad 2 just because of the connectors beeing standard BNC versus the small connectors on the Quad 2. They work ok, it‘s just not so elegant.

With the quad2, you can just use a Din to BNC snake to get to the patch panel or other devices. If you don’t have a patch panel, it can be a pain to have different connectors. I like the quad 2 because it is more compact, and with the patch panel it just requires a different snake.

Here is what I am running:
Threadripper 1950x (excessive for CasparCG, not for ffmpeg encoding)
32GB Ram
1TB 960 Pro NVME SSD
Quadro k2200 (caryover from last machine, will upgrade when needed)
Quadro K4000 (donated card)
Decklink Quad 2

If you want to use screen consumers, I would recommend a better graphics card. Running 1 1080i channel and 1 SD channel both with screen consumers for testing results in 40-50% using just the k2200 graphics card. Without screen consumers it is very light on the gpu with that configuration. If you are planning on using it for playout, make sure you have the storage bandwidth. Even NVME ssd’s experience reduced throughput under multiple sequential reads. That said, I have mainly hit that limit during multi file ffmpeg encodes, not using casparcg.

You really need to look at the hardware requirements of each producer or consumer you plan on running on each channel. Specifically storage bandwidth if you are playing/saving high bandwidth video, graphics card requirements for complex renders, and cpu if you plan on running multiple encodes. I would be happy to run some benchmarks to evaluate various setups if you need an evaluation of the k2200. A pascal based card would most likely be preferable. Both of the cards in my system are most likely for sale if I can get my hands on a pascal based card.

Great, many thanks all!

It’s just going to be disk producer and decklink consumer, no screen work and quite basic content. I’m looking at the Pascal cards as well but does require a more costly processor to handle the number of PCIe lanes, based on the usage and seeing yours @zcybercomputing I’m thinking I’ll get away with K2200…

On the connector topic its mostly just preference. We have boxes of every type of connector in the office so it’s not obtaining or crimping the DIN types that’s the problem, just easier to fault find kit on standard BNC connectors if possible. If it has to be a mini connector then prefer HD-BNC as a more robust connection (and cheaper as we buy more boxes of them) but Blackmagic doesn’t use those.

You probably will be OK with the k2200, but keep in mind GPU copy bandwidth is still required when outputting to decklink. What codecs and filet yes do you plan on using? I am in the process of evaluating performance bottlenecks so I would be happy to run some tests. Don’t forget to consider cpu core count…

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