Submitted 1 year ago by L4s@lemmy.world [bot] to technology@lemmy.world
https://philip.greenspun.com/blog/2021/03/22/why-arent-motherboards-mostly-usb-c-by-now/
Why aren’t motherboards mostly USB-C by now?::I’m beginning to think that the Windows PC that I built in 2015 is ready for retirement (though if Joe Biden can be president at 78, maybe this PC can last until 2029?). In looking at new des…
USB A is still really common, especially for plug in peripherals…
*most common
So, much as I hate to admit it, the real reason for this is bandwidth. Lets look at the best case scenario without dipping our toes into server grade hardware. AMD CPUs tend to have more I/O bandwidth allocated than Intel, so we’ll take the top of the line desktop AMD CPU as of right now, the Ryzen 9 7950X (technically the X3D version is the actual top of the line, but that makes certain tradeoffs and for our purposes in this discussion both chips are identical).
On paper, the 7950X has 24 PCIe 5.0 lanes, and 4 on board USB 3.2 ports on its built in USB controller. So already we could have a maximum of 4 type-C ports if we had no type-A ports, however in practice most manufacturers opt to split the difference and go with 1 or 2 type-C ports and the remaining 2 or 3 ports as type-A. You can have more USB ports of course, but you need to then include a USB controller on your motherboards chipset, and that in turn needs to be wired into the PCIe bus which means taking up PCIe lanes, so lets take a look at the situation over there.
We start with 24 PCIe lanes, but immediately we’re going to be sacrificing 16 of those for the GPU, so really we have 8 PCIe lanes. Further, most systems now use NVMe M.2 drives, and NVMe uses up to 4 PCIe lanes at its highest supported speed. So we’re now down to 4 PCIe lanes, and this is without any extra PCIe cards or a second NVMe drive.
So, now you need to plug a USB controller into your PCIe bus. USB 3.2 spec defines the highest supported bandwidth as 10 Gbps. PCIe 5.0 defines the maximum bandwidth of a single PCIe lane as a bit over 31 Gbps. So the good news is, you can successfully drive up to 3 USB 3.2 ports off a single PCIe 5.0 lane. In practice though USB controllers are always designed with even numbers of ports, typically 2 or 4. In the case of 4, one lane isn’t going to cut it, you’ll need at least 2 PCIe lanes.
I think you can see at this point why manufacturers aren’t in a huge rush to slap a ton of USB type-c connectors on their motherboards. With a modern desktop there’s already a ton of devices competing for limited CPU I/O bandwidth. Even without an extra USB controller added in it’s already entirely feasible to come dangerously close to completely saturating all available bandwidth.
Thank you for the detailed and enlightening explanation!
They don’t all have to be high speed. For example, we already see a distinction in USB-A based on things like power and data speed. I don’t see why anyone would be surprised at a similar arrangement for USB-C. Let me have my low speed keyboard and mouse ports, my low power watch charging port
While that is true, it does cause some headaches for end users. There’s a (barely followed) code for differentiating the speeds of type-A connectors, but I’m not aware of any such system for type-C. Generally people expect a type-C connection to be full USB 3.2 or USB-4 speeds (not to mention the absolute state of the USB spec with them changing the nomenclature constantly). If you started putting USB 2.0 ports with type-C connectors you’d quickly find people complaining about that I’m sure.
Really, in the long term I’m sure in another CPU generation or two we’ll have enough bandwidth to spare that manufacturers can start putting extra USB 3.2 or USB 4 controllers on the motherboards at which point they’ll be able to replace most of the type-A ports with type-C without losing speed. In practice though I expect we’ll see history repeating itself with “low” speed type-C ports and high speed type-C ports that support whatever the latest and greatest USB spec is, and no doubt some kind of distinguishing mark to differentiate them. We already see something like that with lightning, although that’s just a little too proprietary to really cut it, we’ll need to get something that’s part of the USB spec itself.
It does though - the latest USB has a minimum of 20 Gigabit.
I think power delivery is a concern too. If a motherboard had 4 USB-C ports on it, you know someone would try to plug in 4 USB-C monitors at 100W (20V/5A) each, so 400W going across your IO bus. At that point if your motherboard doesn’t just burn out, and you have a big enough power supply to provide it, you’re still going to have a serious heat problem.
Don’t support 100W power delivery on all ports then.
Not al usb c ports have to gen 2.2, just a few 3.0 ports would be neat.
Isn't this glossing over that when allocating 16 PCIe lanes to a GPU, most I/O connectivity comes from the chipset, not directly from the CPU itself?
There'll still be bandwidth limitations, of course, as you'll only be able to max out the bandwidth of the link (which in this case is 4x PCIe 4.0 lanes), but this implies that it's not only okay but normal to implement designs that don't support maximum theoretical bandwidth being used by all available ports and so we don't need to allocate PCIe lanes <-> USB ports as stringently as your example calculations require.
Note to other readers (I assume OP already knows): PCIe lane bandwidth doubles/halves when going up/down one generation respectively. So 4x PCIe 4.0 lanes are equivalent in maximum bandwidth to 2x PCIe 5.0 lanes, or 8x PCIe 3.0 lanes.
Am I throwing away all my mice, keyboards, DAC, digital pens, and other peripherals just so I can have a connector with more bandwidth than I’ll ever need? Nah.
On the other side of that, I’m already stuck throwing away all my Lightning cables and chargers, and ideally want to change only once. Why is it so hard to jump right to C for everything?
What on earth would possess folks to replace their often expensive existing peripherals for no benefit? To totally get rid of USB-A a person will either be out a bunch of money or be stuck with having to keep track of adapters for all their devices they can currently just plug in. An industry move to do so would necessitate the creation of a huge amount of e-waste and would net everyone else precisely nothing.
USB-C is great for mobile devices as it’s small, relatively robust, easier to connect, and does pretty much everything from power deliver to video to connecting any device imaginable. Desktops (and even laptops really) don’t need to place such a premium on port size. Laptops and other mobile devices standardizing on USB-C for power is great. We can charge all our devices from the same charger. Fantastic!
Making 20+ years of working equipment harder to use and forcing billions of people to buy stuff they don’t need (and that many can’t afford) would be wild.
Expect to continue seeing USB-A for a long, long time. No need to replace anything with a USB-C version until it breaks (and maybe not even then).
But we’re not at the point of debating whether users should replace all of their devices. If motherboards with a single USB-C are so common, we’re actually at a place where we’re expecting users to buy all their new peripherals to be USB-A as well.
Usbc connectors are expensive and more difficult to drive. Usb-a connectors are cheap and easy to drive
Not to mention the numerous amount of accessories that use USB-A. My keyboard, mouse, and flash drives all use USB-A.
In my cable collection, odds are that if a cable has USB-C on one end, then either USB-A or C is on the other end. That means every other connector still requires USB-A or a dongle.
USB-A‘s longevity (~20 years) basically ensures that until it’s much cheaper to use USB-C, it won’t replace USB-A.
I agree most motherboards should at least come with 2 or 4 USB-C ports.
That being said, people upgrading all their peripherals happens significantly less often than the PC upgrade itself, and 90% of my current setup relies on USB type A, so if a motherboard (specially mATX) needs to decide what ports to fit into limited space, I’d prioritize USB A for sure.
Yeah, I’ve got mostly USB-A peripherals, and the USB-C ones are using a USB-A to C cable anyway. What I’d actually want is graphics cards with the same Thunderbolt type ports that laptops have, so the USB stuff can be pushed through the same cable to your monitor.
How the heck is USB-A a legacy port and what would I do with 11 USB-C ports on a PC when everything I plug into it besides my phone (depending on the cable) has a USB-A connector? Like how would I even use something as simple as a flash drive or Bluetooth/wifi/radio transmitter?
USB-C makes a ton more sense for mobile devices, docks, and charging, but not so much when you’re plugging them into a suitcased size brick that doesn’t move. I could see useful applications for something powered that needs a lot of bandwidth, but PCs also come with dedicated ports for all those peripherals too.
A cheap USB hub solves everything you are describing. You can just leave it dangling from behind.
Saying that, I’m not in favour of only usb-c motherboard though.
Cheap USB hubs get fried if you try to use it with something that requires power feed. Or usually just feed the whole voltage to one of the connectors, have fun finding out which one. Fully competent dock hubs are not cheap.
I just bought a cheap kitchen scale that has a USB-C connector, used for charging the LIR2450 inside.
Because there is no reason to have more than 1 or 2 since almost everything uses a type A connector.
Standard USB type A ports are cheaper, and more importantly, STURDIER then USB C ports. This is extremely important for peripherals that do not need to be disconnected and reconnected often.
USB C is great for convenience for certain things, but it’s a weaker port in terms of physical connection strength.
Most desktop peripherals are still USB-A. For low-power, low-data things like keyboards and mice, what would be the point of USB-C? It would increase the cost of the product but provide no real benefit to the user.
Also, if you had a new desktop motherboard with say 6 USB-C ports, would you expect all of them to be capable of delivering 20V at 5A so they can be used to drive USB-C monitors &etc? Because that’s a lot of power to be running across your motherboard, even if you have a power supply that can handle it.
USB-C is very hard to manufacture and expensive as fuck as a result.
thats why.
Especially when most devices don’t need the bandwidth or power needs of USB-C.
Source? Why is it expensive?
Pretty sure this person is just talking out of their ass. I found one source from four years ago that showed a price difference of about a buck to manufacture. Yes, that is more expensive, but passing that dollar onto the consumer for some USB-C ports on a motherboard seems pretty reasonable, and by now I’m sure that gap has decreased significantly.
I dont remember off the top of my head, but it has like 22 or 24 very very fine wires in it, that have to be lined up perfectly on both sides of the connector to be soldered to equally small pads.
So its much more labor and time intensive to make a USB-C connector, compared to a USB Type A, which has big bulky cables and equally bulky (comparatively speaking) pads.
USB Micro/Mini used tiny wires too, but again… only about 2-4. So far less time and labor to line them up, vs the 22-24 conductors inside the Type-C connector.
I’d honestly love to see everything USB-C-ified. Would be great to finally just have one standard to concern yourself with.
Nobody tell them about the massively fragmented set of standards using the USB-C connection.
I know, but at least we’d only have one physical connector at that point. While there are indeed a lot of standards for USB C, many of them are not all that relevant in day-to-day use when you’re mostly just looking to connect some basic USB peripherals like a mouse, a thumb drive or charge your phone.
This is about cost. The standard USB ports are far cheaper and they probably already have a billion of them on hand. Plus all the board layouts already use standard USB for their layouts. Also you’re not really getting any advantage from the USB c size wise or performance wise.
Further more now you’d have to make USB c to whatever form cables and make customers buy these new cables.
If u had to choose between 2 computers and 1 made u buy completely new cables for every peripheral which would u buy?
billion of them on hand
Been thinking that for a long time! For example, I can imagine Chinese warehouses jammed with micro USB connectors. Want to build a low-cost widget? Meh, save some pennies per unit and put a micro on there.
Would make much sense. You still want USB-A ports for most peripherals as using an usb-c port to connect a single mouse would be pretty much wasting a port.
However adding a Thunderbolt4 port or two along side the usual USB-A ports would be nice.
This was written in 2021. Is it still true?
I have never seen a desktop motherboard with more than 2 type-c ports. I just went and did a quick look through all the Intel and AMD desktop motherboards (I didn’t look at server mo to motherboards) and as of right now still could not find one with more than 2 USB type-c ports.
I believe the idea is that on the newer motherboards is that the high speed (20Gbps) USB-C ports are ideal for external hubs. Personally, I like my workstations to be under my desk and out of my way and having one USB-C cable for a hub and one for my phone is clean and convenient.
USB-C to USB-A hubs are cheap. I am constantly moving thumb drives back and forth between my PC and my 3D printer and CNC so damage to an integrated port on my PC would be a real possibility.
Everyone has their own usage habits, of course. For me being restricted to two or maybe three built in USB-C ports is for the best.
Yeah, this is still true for ASUS boards at least.
I would like to see a new USB form factor for chonky hardware like desktop PCs that combines the sturdiness and reliability of USB-A with the symmetry and power delivery of USB-C
My kids laptop has 4 IIRC. Getting a PC motherboard with more than one on rear and one connector for front of case was impossible last I looked. I generally keep my pc’s for about 5 years and wish to future proof somewhat. It is beyond ridiculous at this point. Although, I haven’t tried to buy one for a few months so perhaps this has changed.
yeah and good luck getting a case with multiple USB-C front panel. I don’t even think I’ve EVER used the USB-A on the front of my case
I like USB A for thumb drives and other legacy equipment but I definitely prefer more USB C. Right now, I have a connected to my laptop through it, one for charging and then 2 USB A for peripherals. I’d personally trade the other two USB A and use a small hub instead so I can charge my phone, watch and vape without a separate charger.
my thinkpad has two usb-c ports, both can be used for charging. i still prefer usb-a cuz i still use peripherals and drives i have right now. im not ready throw them away for the sake of “newer ports.”
bandwidth and room on the board mainly
Srticke is two years old. I wonder if it’s still relevant, especially after the EU standardization change
I’m still on the Ryzen 5xxx platform and there aren’t a lot of motherboards that have USB-C either unless you go high end like the ASRock Taichi.
Definitely need the ports though given how ubiquitous USB-C is nowadays.
Thankfully there are pcie cards that provide plenty of USB-C ports, but that we have to do that at all is annoying.
Where does L4SBot pull data from? R*ddit?
BetaDoggo_@lemmy.world 1 year ago
There’s no reason to replace USB A on most desktops since it would break 20+ years of backwards compatibility without any real benefit. Maybe 1 or 2 would be useful.
DacoTaco@lemmy.world 1 year ago
Thats the thing, with a small adaptor that has no logic/silicon, usb-a device is fully compatible with a usb-c port. And things like framework solved this issue ages ago to make hardware expose either, or both, usb-c and usb-a…
JohnEdwa@sopuli.xyz 1 year ago
If manufacturers start making printers, mouses, keyboards, headsets and all other peripherals with usb-c cables and provide c to a adapters in the boxes, then motherboard manufacturers should start adding more ports to support them without those adapters.
But the Apple way of changing all ports to USB-C because “you can just use dongles!” is dumb.