Blackmagic Forum

Hi!

Wanted to know if anyone tried this specific setup (or have some knowledge if it would work). Let's say I have a laptop with thunderbolt (not neceserilly MAC), and I have Thunderbolt PCIe extender device (one that allow you to extend your laptop with external PCIe cards).

I connect my 2 x DeckLink Quad card to PCIe extender. I connect 8 HD-SDI inputs, working in 720p resolution. Additionaly I connect my FireWire PCIe card, to which I put my Audio Interface, with 8 audio inputs (48kHz/24bit bitrate).

I will not be capturing the video sources to the disk! All I need is to view them in Resolume software (program for VJing), and route them on some external display.

So now the question - is Thunderbolt capable to flawlessly deal with that many data? And of course, is the good, powerful CPU (like i7-4700HQ 2.4/3.4) capable to manage it?

Hi,

In pure mathematics, 1.5Gbps x 8 = 12Gbps, which is past the 10Gbps nominal capacity of 1st generation Thunderbolt.

Some of the latest models of Sonnet Echo Express expansion chassis will support 2nd generation Thunderbolt (20Gbps). Currently they're obviously designed for the new (and soon-to-be-released) cylinder Mac Pro, which seems to be the only known computer to support Thunderbolt-2 (correct me if I'm wrong). Also, it appears to be much more portable than its tower-type predecessors, so perhaps a viable option (no idea about the pricing though).

Martin

Thanks for reply!

Why 1.5 Gbps? 1.5 Gbps = 187.5 MB/s. From what I've read 720p signal (8-bit, 60 fps) is equal 105 MB/s. 105*8 = 840 MB/s so still under the 1000 MB/s thunderbolt limit.

You may be right about the 720p signal, but the real life strikes at both ends - it appears that due to 8bit/10bit encoding (and the resulting 20% overhead) the actual Thunderbolt bandwidth may be limited to ~8Gbps (1GBps).

Just so you know the new Asus Z87 Deluxe Quad board also has Thunderbolt 2 sockets, although getting one yet is a bit tough

As for Thunderbolt 1, this is what is says on the Sonnet website.

"The PCIe slot will physically accommodate up to a x8 PCIe card, however the actual electrical bandwidth of Thunderbolt is x4."

That's because both Thunderbolt 1 & 2 are just a PCI-e 2 x4 bridge, so the equivalent of putting a 4x card internally. The main difference between Thunderbolt 1 & 2 is that TB 1 gives 2x10 and TB 2 gives 1x20, but they both use exactly the same PCI-e 2 x4 bus

It is risky to use this on a laptop. There will be high bandwidth and high CPU usage. I suggest going with desktop PC, since you will be able to replace different parts to better ones if it will be too slow to perform. I use DeckLink Quad on a desktop and it works well.