Video Games Tutorials and News - I Spent $1100 On Displayport Cables. For Science

Video Games Tutorials and News - bit rate

Punishment time This enormous pile of 2b tested displayport cables comes from all the most popular brands: Amazon Basics, Monoprice, Best Buy, and more. We bought three of each at various lengths for the most popular models to give us multiple data points. We are going to be painstakingly running all of them through our total phase cable tester to see who has the good stuff and who has the crude stuff.

I know our sponsor, Build Redux, has the good stuff. They create PCs for gamers who want to win and who want high frame rates without breaking the bank. Okay, I lied a bit. The cables have already been tested at their rated speed and if they passed, we pushed them even further to see who is under promising and over delivering.

We did over a hundred runs in total and ended up with this masterpiece of a spreadsheet. You are proud of this one, aren't you?

Why displayport

Why displayport

Nerd Why are we testing the displayport? It's partly because we already tested hdmi and got a lot of requests to follow up with displayport, but the other half is that people like me and Willow over at Level 1 Tech, who apparently actually went out and bought one of these cable testers after our last article, have had a lot of issues with displayport over the years, from intermittent signaling issues to outright dead cables, and I think it's about time I figure out why each cable went through our total phase cable tester at the spec that it's rated for now.

There are a total of eight versions of displayport, two of which are minor revisions that don't change much, so we'll acknowledge that they exist and move along, and even some of the numbered ones, we didn't have to do much with displayport versions 1.0 and 1.1. They are relatively ancient, so that's part of why we're not testing any of those cables here, but the real reason is that they weren't widely adopted, so most cables are rated for at least displayport 1.2, and it's the same story for displayport 1.3.

It was superseded by 1.4 almost immediately, which carries the same bandwidth but adds support for display stream compression.

What's left

What's left

12 forward error correction and hdr10 metadata That leaves us with three display ports that matter: 1.2, 1.4, and the upcoming 2.0 spec in consumer terms. The biggest difference between these three is that each one is rated for a different maximum bandwidth. The higher the number, the faster it can go.

Now there are multiple ways to hit that limit. You could crank the resolution, you could crank the refresh rate, you could crank the color depth, or realistically, some combination of those three, and then you just won't be able to go any higher unless you enable display stream compression. We could talk a little bit more about that later now.

Manufacturers and testing

Here are the manufacturers we're talking about today. You'll be familiar with many of these from our HDMI cable testing article, where we covered some things in more depth that we're going to gloss over a little bit today, like how digital signaling works. We're going to have a card on the end screen if you're playing catch up now.

Here are our tests. We have three groupings. Tab one in yellow are the cables that we're testing in triplicate to eliminate flukes. These are the most popular ones, and we're expecting most of you to actually buy them. And finally. Tab 2 in orange is single samples of 9 of the top 10 cables on Amazon, and finally.

Tab 3 in blue is cables that we sampled from around the office, including bundled cables from monitors made by Aorus. Samsung, and Asus RoG. All right, Colin, show us what's behind tab number one. Every single one passed. That's not what I was expecting.

Hdmi vs. displayport

Hdmi vs. displayport

Both of them have four shielded twisted pairs of conductors. You could think of them kind of like the sides of this lanyard, but in hdmi, only three of them carry data, with a fourth kind of skinnier one that's just reserved for clock pulses. Displayport takes advantage here by using all four shielded pairs to transmit data.

You know what, this isn't working. Let's just do a different visual new color of lanyard on lttstore. This allows each pair to run at a lower frequency while maintaining overall transmission parity with HDMI. So with 12 of the 20 conductors used for the signal plus signal minus and ground connections, that leaves eight other conductors that are used to run a configuration channel, an auxiliary channel, and a power connection.

The power connection actually goes unused in common cables, though, and is reserved for use in devices with integrated displayport cables. Having these wires connected can actually cause a short-circuit condition that was a problem in the past, particularly with cheap mini displayport cables. By the way, those locking tabs on the end are not actually part of the official displayport specification.

They are nice to have, though.



With respect to our results, we can gather that this reduction in signaling frequency is contributing to better signal integrity, leading to displayport cables' being more consistent than what we saw with hdmi, so if you're buying a brand new cable today, cheap is probably cheerful and infinite cables once again topped our list for the lowest cost per foot, followed by Amazonbasics.

But we're not done yet. Inside the dense document that is the displayport standard, there exists a set of definitions for transmission modes. These are the bitrates that displayport can transmit data at. We're not talking about resolutions per se, but rather the speed at which the cable operates at full stop.

Displayport 1.4, for example, is compatible with four different transmission modes: rbr, hbr, hbr2, and hbr3, which peak at 8.1 gigabits per second per lane. That means, with four display ports, 1.4's peak bandwidth is 32.4 gigabits per second. That is significantly. Less than the 48 gigabit per second maximum of hdmi 2.1.

Interesting displayport applications

Interesting displayport applications

I am not calling it that ; to get around this, some applications of displayport have implemented more than the usual four lanes. Apple famously created a custom eight-lane displayport 1.2 interface to drive the first 5k Imac and Thunderbolt can also have up to eight lanes, allowing them to carry two display signals over a single cable.

The long-term solution, however, is displayport 2.0, which can run in three new modes named according to their per lane bitrate.

Amazon's best sellers

Now we'll talk about why that matters shortly, but first let's take a look at our next tab, Amazon's best sellers. How'd they do? Every single one passed again and again.

Now that's crazy. At wild now, they're not an amazing deal cost wise, but at least they're easy to order.

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