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Long Thunderbolt 3 cables with full speed.  

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RickyTerzis
(@rickyterzis)
New Member
Joined: 4 years ago
 

Hi...i am a new user here. I want to know if your computer would not recognize USB peripherals plugged in the back of your eGPU using CalDigits cable? Or, does this mean the cable just can’t be used as a Type-C to Type-C USB? I think it’s the latter. If so, it really doesn’t matter if you use Caldigits.

 

circuit card assembly

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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franketto
(@franketto)
Trusted Member
Joined: 4 years ago
 

Hi, you must distinguish the use of the TB3 cable as:

1) TB3 connection

2) USB-C connection

In the 1) you get all the TB3 speed 40Gbps AND you also get the USB devices on the back of eGPU Mantiz, because they are NOT direct USB connection: they are part of the same TB3 connection.

In the 2) you can't use a TB3 active cable to make a USB-C connection at full speed 10Gb and neither at half speed 5Gb... you can connect USB-C devices only at USB2.0 speed 480Mbps. Instead you can use a passive *shorter* TB3 cable at full speed 10Gbps also connecting directly USB-C devices.

BEWARE of *not TB3* 2m USB-C cables: most times they cannot give 10Gbps connection EVEN if they declare it!!

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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gburns53
(@gburns53)
Active Member
Joined: 4 years ago
 

2 open questions. 

Will there ever be a 3 meter TB3 40 gbps cable?

Do we really need 40 gbps cables or would 20 gbps do the trick for most games? In a laptop -> eGPPU -> laptop screen loop

Spectre x360 - Omen Accelerator - GeForce GTX 1080 - Loop to Internal display


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jefniro
(@jefniro)
Reputable Member
Joined: 4 years ago
 

Apple has added their own Thunderbolt 3 cable... 

https://www.apple.com/shop/product/MQ4H2AM/A/thunderbolt-3-usb‑c-cable-08-m

 

2019 14" HP EliteBook 840 G6 [8th,4C,U] + RX 5700 XT @ 16Gbps-TB3 (AKiTiO Node) + Win10 2004 [build link]  

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Frostillicus_
(@frostillicus_)
New Member
Joined: 3 years ago
 

This is a solid (cheap) option for a 1m ACTIVE cable with full 40Gbps/100W PD

https://www.blinq.com/detail/electronics/desktops-monitors/computer-components-parts/j5create-3-3-active-thunderbolt-3-usb-c-cable-white/1544020?condition=brand-new

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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karatekid430
(@karatekid430)
Estimable Member
Joined: 4 years ago
 

Hello,

Take a look at my post which I solved myself. The Nekteck 2M Thunderbolt 3 40Gbps 100W Active cable allowed me to hit the theoretical limit of 22Gbps PCIe for the first time. I thought the utility was under-reporting, and before my Dell 9370, I thought my Dell 9365 had a bottleneck. I could not explain why my experimental desktop with GC-ALPINE RIDGE AIC was slow as well.

https://egpu.io/forums/thunderbolt-enclosures/low-h2d-bandwidth-result-dell-xps-9370-aorus-gaming-box-0-5m-cable/

Turns out the passive 0.5M 40Gbps cable that came with the eGPU (plus another one from Startech) were underperforming, but the 2M Active one blew them away.

I do not know if that means the Dell laptops and / or the Aorus eGPU are not strong enough at signalling to drive the connection without losses. But it is worrying if the cables that come with things are not performing. Especially since the throughput limit on Thunderbolt 3 is 22Gbps when DisplayPort is not put through it. So if a 40Gbps cable was struggling to make 22Gbps (actually more like 15Gbps in my case), that is disturbing.

Can anybody else test their passive 40Gbps cables and post results, please? If you have a Radeon eGPU, you need AMD-APP-SDKInstaller-v3.0.130.135-GA-windows-F-x64.exe and open CMD and run the command "%userprofile%\AMD APP SDK\3.0\samples\opencl\bin\x86_64\BufferBandwidth.exe". For Nvidia, people seem to use some CUDA-Z program.

If you have active cables, feel free to give comparisons.

If anybody knows how to test eGPU bandwidth in Linux and Mac, please say! Normally I don't give a rat's **** about Mac, but it will mean that people with Macs can run tests for us without dual-booting.

My best guess is taking the source code from AMD APP SDK for the BufferBandwidth.exe and modifying it to work with Linux and OpenCL. Theoretically it can then be made to work with Nvidia - because OpenCL is open. I hate CUDA - anything that confines to a single hardware vendor (hence hatred of Mac).

 

Edit: the download links for the AMD APP SDK 3.0 have been recently extremely hard to find. Last time I just found the installer off another computer in the Downloads directory and moved it to another. But turns out if you search for the exact file name, you get this:  https://community.amd.com/thread/203821 with direct download links.

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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karatekid430
(@karatekid430)
Estimable Member
Joined: 4 years ago
 
Posted by: gburns53

I would also like a 3 meter tb3 cable. Doesn't appear they exist. Would like to use my laptop on my sectional couch, there's a distance issue to the nearest table. The 2 meter cable would require me sitting up and moving over, nooooo!

Is this because 3M Thunderbolt 1/2 cables existed? I noticed that. None for Thunderbolt 3.

Corning have optical Thunderbolt 3 cables in the pipeline, supposedly. Somebody speculated that the delay is due to a high failure rate of Intel-branded transceivers with optical Thunderbolt 1/2 cables, and no other manufacturers were able to provide them. Hence they are waiting for the royalty-free thing, and hopefully Intel lifting some restrictions on manufacturing. I also hope they make it with some copper cables running with the optical for power delivery (100W).

What would be cool would be a pair of boxes, each with a Thunderbolt port, a power adapter, and an SFP or QSFP transceiver slot. That way each end could connect and charge the device up to 100W, and in between you could just use an LC optical Ethernet patch cable in between, which can be obtained from 0.5M to an order of kilometres in length.

Intel could at least define a device with a Thunderbolt controller and two ports for daisy chaining, that does not actually count as one of your six in a chain - no other ports, no function other than to do the 3 Rs to repeat the signal ( https://en.wikipedia.org/wiki/Optical_communications_repeater#Classification_of_regenerators). As in, it would be transparent and undetectable. And perhaps provide power delivery with an AC adapter. Otherwise you have to use a dock which are extremely expensive, bulky, and will incur a performance penalty, especially for an eGPU attached afterwards.

Otherwise you can cut open a 2M active cable in the middle and try to splice some more cable in - but depending on the quality of the joins and the new cable, and also the added length, you might find it degrades the performance. Or it might not - the active parts at the ends might be capable of more than 2M. You'd probably want to have god-like soldering skills. Definitely needs to be undertaken at your own risk - and will definitely void your warranty.

The female USB-C to female USB-C adapters are presumably dangerous if the cable orientation is wrong - because they will not contain the mux required to handle the opposite orientation. But if you can figure out the correct direction, they might be able to combine two cables. Again, this is outside of the spec and has to be undertaken at your own risk.

To do: Create my signature with system and expected eGPU configuration information to give context to my posts. I have no builds.

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troywright
(@troywright)
Eminent Member
Joined: 4 years ago
 
Posted by: kotlos

I got the AKiTiO 2m:

Here is with the factory 0.5m cable:

I have similar results.
On the left is my CalDigit 2m active cable
On the right is the short one that came with my Aorus 1080
Laptop is Spectre x360 x2 thunderbolt lane

long vs short
2017 15" HP Spectre X360 (MX150) [8th,4C,U] + GTX 1070 @ 16Gbps-TB3 (PowerColor Devil Box) + Win10 [build link]  

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kstl
 kstl
(@kstl)
Active Member
Joined: 3 years ago
 

Hey everyone, 

I'm looking to get a longer active TB3 cable for my setup. Both of the cables recommended in the buyer's guide (the Akitio and the Cable Matters) are super expensive locally. I started looking around for other options that were still 40Gbps but at lower price points in my country. I found these, from CalDigit and StarTech (links are to Canadian amazon store).

Are the cables that are recommended in the buyer's guide there because they've been determined to be more reliable than others? If not, I'd love to suggest that these (and maybe other?) options are added to the buyer's guide for people who might need other options (ie outside of US markets).

2018 13" MBP TouchBar - 10.15b & Win10
modded AKiTiO Node Pro + RX580 8GB
2x Apple Cinema Display


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Yukikaze
(@yukikaze)
Prominent Member Moderator
Joined: 4 years ago
 

To add my experience: The CalDigit 2m cable works just fine as well for my Spectre x360 and Aorus Gaming Box (R9 285).

The bandwidth is looking pretty good (why the heck is the attach an image window still bugging out on me?!):
AIDA64 - Memory Read:  2,628 MB/s.
AIDA64 - Memory Write: 2,331 MB/s.

The result with the 0.5m cable from my original implementation guide was:
AIDA64 - Memory Read:  2,580 MB/s.
AIDA64 - Memory Write: 2,448 MB/s.

Want to output 4K@60Hz out of an old system on the cheap? Read here.
Give your Node Pro a second Thunderbolt3 controller for reliable peripherals by re-using a TB3 dock (~50$).

"Always listen to experts. They'll tell you what can't be done, and why. Then do it."- Robert A. Heinlein, "Time Enough for Love."

 
2020 14" Lenovo ThinkBook Yoga 14s [11th,4C,G] + GTX 1080 Ti @ 32Gbps-TB4 (AKiTiO Node Pro) + Win10 20H2 [build link]  


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