Posted on 08/28/2024 12:45:32 PM PDT by 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?
I was thinking the same thing. A lot of times your standard Menards/Walmart/Best Buy/eBay stuff won’t do the job. I can’t tell you how many cables I’ve trashed because I either bought the wrong kind or they were simply garbage.
Well of course, except that in this case the USB-C port on the computer or expansion card also needs a bit of extra electronics behind it. But, that’s not the point. The point is why is the hardware / software ubiquitous on laptops starting a few years ago, but desktops were much slower to catch up, and most USB-C expansion cards STILL don’t have the capability...
This is not a cable issue. The same cables work fine using the hub off my laptop.
You might want to peruse this thread
https://www.reddit.com/r/UsbCHardware/comments/hpkne6/add_usbc_wdp_altmode_to_desktop_pc/
I like Displayport, I’ve got a couple of Samsung monitors with both DP and HDMI inputs. DP outputs can drive an HDMI monitor (usually) but HDMI ports (AFAIK) never drive a DP monitor.
I’ve used a couple of different USB-A docks with HDMI and VGA output options, both got flakey after a while.
I picked up a Kensington brand USB-A to DP gizmo that isn’t perfect but works fine, the laptop is from 2013 and the HDMI port fell out of the CPU 8 or more years ago. Since I swapped in an SSD, I haven’t had the Kensington go inactive and needing to be reset (unplugged then plugged back in), and that typically would happen a few times a week.
:^)
Check out www.DisplayPort.com for more info.
My two cents from a guy that used to work with Chinese factories designing AV equipment: they do not need to.
There is a cost to using the chipsets (royalties) that support such quality output. The other cost is space. If a board designer is out of space, he can switch to a chipset at a higher price that offers such features.
In a laptop, space is at a premium and choosing a more expensive chipset to put on the motherboard makes sense in 2024.
In a desktop space is not such an issue, but sometimes heat dissipation is an issue. So they use a larger connector (space) rather than a usb 3.1 or Thunderbolt connector since they can.
Everything is a balance, from heat to space to cost. If the volume isn’t very high on a production run, then the cost will be high.
Looking over that $92 card, it goes the other extreme and offers way more capability than what I need, or would ever need. It’s impressive tho’!
https://www.newegg.com/p/17Z-00A0-001A5
I’m going to take a guess that the longer cables need to have lower capacitive and inductive losses per foot than a 6 foot cable. So you are likely talking about a quite bulky cable compared to the usual. Very crudely it’s analogous to “in the old days” I had a long run of RG-6 coax to my outside FM antenna. Replacing the original RG-59, the RG-6 definitely made a difference when I was trying to pick up KSHE in St. Louis!
Noted, although the laptops seem to have made the transition about 5 years ago. The DP enabled USB-C ports ARE showing up on newer desktops. Possibly the proliferation(!) of USB-C hubs with HDMI output helped drive that?
And still... the lack of expansion cards with “DisplayPort” enabled USB-C outputs is a bit of a mystery. I’m guessing that somehow the desktop motherboards typically didn’t support such expansion cards without a lot of wizardy in the expansion card?
The chipsets that enable DP-alt are more expensive, and are simply better suited for laptop low power usage, based on cost.
If I had to quess. I would say PCs are more often used in schools or business, and to keep people from stealung data or introducing a virus....
Laptops are of both a budiness variety and personal ownership.
Thus a possible explanation is from a business support requirement to protect PCs from users, esp. on networks.
Well, I don’t see how adding what is essentially a “video port if desired” capability to a USB-C port that is provided anyway makes it easier for a hacker to steal data or introduce a virus, but, then, I’m not a hacker or nearly good enough at this stuff to be one. :-)
But... The machines end up costing about the same, and newer desktops have that same capability.
I’m guessing that desktop makers 5 years ago simply had space to add an additional (second or third) Display Port, and it was cheaper to do so. In a laptop, especially as thickness keeps decreasing, space to add a DisplayPort is at a premium, at the same time the small screen drives up demand for additional external display options.
Now that many users have USB-C hubs with HDMI outputs, like me, those users, like me, would like DP alternate mode to be available from their desktop’s USB-C port.
In any event, in MY situation, my primary display runs off the 1st DP port on my desktop, and to run my secondary display, which is HDMI (for best resolution input), I’ll just get a DP-to-HDMI adapter. The USB-C multi-function hub will sit on my desk with the HDMI port doing nothing but grinning at me. :-) Should I wish to send HDMI across the room to a TV, I can yank a graphics card* out of one of my other machines, or, more limited (parallel display of “second DP output only”), get a HDMI switch or splitter.
*Said graphics card doesn’t have 4k output, but said TV is not 4k anyway.
Thanks for the responses, All!
He’s provide different power than an expansion card. You likely have a dedicated power supply for the hub that can push more juice than might be needed. PCI cards have to abide a specification to prevent damage elsewhere in the device. Get a USB tester and see what voltages you’re getting. I’d bet that you’re getting stable voltage off the card but surging on the hub.
THIS!
Cool idea! Let’s do it. I have no idea how to do it. Lol!
You probably have already done this. But I would be doing intelligent searches on eBay for the card of your dreams. Used might work out for your oddball request. eBay has loads and loads of inventory, due to the slowed down economy.
After eBay.... search Amazon too. But eBay is numero uno.
For the time being, my solution for my 2nd monitor (which is a 4k TV that has no DP input) is to output DP port #2 on the rear of the desktop machine into a DP-to-HDMI (4k) adaptor that will feed the TV. Either of my USB C hubs can plug into the desktop’s USB C port, but the hub’s (useless) HDMI output will just sit there and grin at me. If I want to send a HDMI output to the TV across the room, my best bet is to swap in an inexpensive used graphics card I already have that is not terribly needed in the machine it is in. If I need more USB-C ports (likely) I can try an expansion card with multiple USB-C ports, or a high speed hub with a USB-A input and multiple USB-C “outputs”. (Daisy chaining hubs is also theoretically possible, but I’ve never found it to work well.)
That thread you linked to is very interesting, but, the CURRENT version of the 1st expansion card suggested costs considerably more than my new desktop machine did. Used cards (including alternatives suggested) may be available and I’ll keep an eye out for them... Specific cards to look for really helps with the searching. :-)
That thread also suggests the graphics card (only) route, but a graphics card PLUS an inexpensive USB-C expansion card lacking alt DP via USB-C capability is a logical next thought.
Thanks!
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