Why are PCIe expansion cards with a DisplayPort capable USB-C port (DP alternate mode) hard to find for desktop PC's?

Me | 8/28/2024 | Paul R.

[Paul R.]

Here is one for our FR computer gurus: Why are PCIe expansion cards with a DisplayPort capable USB-C port (DP alternate mode) hard to find for desktop PC's? Many laptops, like my Dell Latitude 5490, have a DisplayPort capable USB-C port. Yet it seems most desktops of roughly the same vintage, such as my Dell Precision 3430 (and many a newer desktop too), do not have a DisplayPort capable USB-C port. (My 3430 has a high speed USB-C port, but it is not DP capable.)

Why the omission on the desktops?

[Paul R.]

This question came up when I bought on of those multi-function (port types) USB-C hubs which includes a HDMI output. That will not function when the hub is connected to the USB-C port on the front of my 3430, as that port is not DP capable. "No problem", I thought, as I want to add an expansion card to put a couple USB-C ports on the rear panel anyway -- I'll just get one with DP capable (Alt mode) USB-C ports. But... these are very hard to find for a reasonable price ( < $ 40 ) and even then if I spend well over $100 (approaching what I originally paid for the 3430!) they come only in full height cards, it seems.

This is not making sense to me - the USB-C alt-DP capability doesn't seem to substantially run up the price of the laptops it can be found in. ???

I'll probably just get a 2-port USB-C expansion card (without the alt-DP capability) and since I'd like to have HDMI output capability, I'll get a DisplayPort to HDMI adapter to plug into the second full size DP port on the rear panel. But I'm curious as to the reason desktop expansion panels with USB-C alt-DP capability are rare.

???

[Paul R.]

Thanks, All!

[Red Badger]

Probably so you can buy a high-end video card to play video games...............

[Red Badger]

Pingarootie!............

[Larry Lucido]

The headline reminded me of a line from die hard 2. “We have a new SOP for DOAs from the FAA.”

[Steely Tom]

I’m not an expert in the precise nature of what you’re trying to do, but I found numerous cards that appear to do what you want by just typing “PCI-e to usb-c” into Google.

Newegg seems to have the exact item you’re looking for, priced at $40.

[alancarp]

I was trying to connect a computer-based USB-C port to a MIDI keyboard earlier in the year and discovered something that frankly shocked me: once the cord length is greater than 6 feet, the data connection utterly fails.

I tried several different cables (I really wanted a 15-to-20 foot cord... simply for reasons of geography in my workspace), but they all failed to deliver data between the computer and the MIDI board. Only when I got to 6 feet did it work.

Mind you, if all you need to do is charge a device with USB-C, then you’re fine... 10 feet, 20 feet... no problem. Also, USB-A (with lower USB protocol versions) also work at longer lengths. But not USB-C and definitely not at the faster data speeds of USB2.0 and USB2.1 or higher.

[alancarp]

(Oh, one more thing: I did buy a PCI-bus card to give me dedicated USB-C ports on the computer... didn’t help: it was all about the cable lengths vs. the data rates.

[GaltAdonis]

”…so you can buy a high-end video card…”.

.

Yup.
Money.
It all comes down to money, IMO. (Surprise!)

[Mr. K]

I like the Yellow bus. Don’t we all love the yellow bus??

[bak3r]

I believe you can get USB-C cables with signal boosters. The MIDI probably doesn’t have enough juice, the PC is probably fine. I’ve regularly used 12’, 18’ and 20’ USB-C cables to connect 4k 60fps cameras for event streams without problems.

[dayglored]

Wow, PCIe expansion cards, DisplayPort connectors,.... Feels like a blast from the past (for me) since it's been at least a decade and a half since I had a desktop computer that had PCI slots. Sorry, I'm of no tech advice use here.... but I'll put in a windowspinglist ping for ya.

PCIe and DisplayPort ... PING!

You can find all the Windows Ping list threads with FR search: just search on keyword "windowspinglist".

Thanks to Red Badger for the ping!

[Rocco DiPippo]

I tried several different cables (I really wanted a 15-to-20 foot cord... simply for reasons of geography in my workspace), but they all failed to deliver data between the computer and the MIDI board. Only when I got to 6 feet did it work.

Get a long USB cord which has a built in repeater. I'm running a ~15 ft long one from my Vdrum's usb midi connection to the workstation in my recording studio. Works flawlessly.

[Sirius Lee]

We should start a music/tech/recording ping list.

[rarestia]

Check your cables. Not all cables can carry the voltage and longer cables have sufficient voltage loss that a monitor won’t power on. DisplayPort has standards for stability and a LOT of stuff on the market is trash. Check the DisplayPort website for registered and supported vendors for their 1.2 standard.

[alancarp]

My look at that found few that were USB-C to USB-C... most of them I’ve found have a USB-A on at least one end. I admit my fear is this: while I see cables with repeaters from 20 to 40 ft. (even 50 ft!), I’m a bit shy of spending the money on that since I start having trouble above 6 ft.

In any case, it’s working now that I rearranged the room to accommodate a shorter cord :D. Will definitely revisit if I have to move everything around again!

[Jumper]

USB was initally a slow transfer or connection. High volumes of data required for video might overload the transfer rate. If you don’t have the software or drivers, you don’t just get this by plugging in a USB without them. There are different standards for video and sound, as well as documents or pictures. Without the correct software and/or drivers a computer cannot just product or translate the files.

USB is not a sound device. USB is not a video device. USB is not always a storage device, or just a power device. USB is a standard connection. Everything else depends on the cable or the software.

[ImJustAnotherOkie]

For hubs you need to get smarter cables.

[Paul R.]

That’s what I originally thought, but, the problem is, unless the card (the port, actually) specifies a capacity for DP alt mode, the connection will not provide video through, say, a HDMI adapter or a hub that connects via USB-C. I have multiple hubs, including one from Dell, with HDMI output that works if plugged into the USB-C (DP) port on my laptop. Try the same thing with the USB-C port on my desktop (which is not USB-C DP capable) and the same hubs fail to provide output from their HDMI ports. Most of the expansion cards sellers specify, if you dig deeply enough, that their card (s) USB-C ports do not provide DP alt mode.

Now, If you’ve found an expansion card for $40 that DOES provide DP alt mode, that’s great. But I’ve started looking through the cards on New Egg (they have quite a selection at $40 or less) and so far, no dice.

This card, for example, won’t do the job:

https://www.newegg.com/p/17Z-00VP-00001?Item=9SIAMZWBZB3194

This one, for $92 will:

https://www.newegg.com/p/17Z-00A0-001A5

But dang, the laptop was a $120 refurb...

However, your link to New Egg IS useful, as I can find specific card models there that might in turn show up used on eBay. Previously I’d only found two such models on Amazon and they were in the $170 plus range. :-(

[Paul R.]

But, mfgr’s like Dell give you the capability for almost nothing extra ($$) in their laptops...