DisplayPort cables?!? Whadda we need stinkeen Displayport cables for?!

[BonzaiDuck]

[You can find out how this turned out at the 3-12-15 post to this thread by Bonzai. . . ]

I'm playing catch-up on display interfaces. I'm also currently using my new monitor to do "video-switching" to supplement an old KVM, and it's working out well as a stopgap measure. I have a better idea for replacing the KVM -- to be "4K-ready." I'll put it off until I feel flush with some extra cash to pay for it. It's not cheap.

I need an 8' Displayport-to-Displayport cable (no "mini-DP") that is of good quality and -- especially -- which meets the latest standards. I thought this was DP 1.3, but I'm not sure.

All I see are 10' cables, and if that's all there is, that's the next best thing.

Any recommendations? C2G doesn't seem to offer a lot. Can't be sure about the Egg. MyCableMart didn't seem too promising.

Maybe someone can point me in . . . some direction . . . [and-yeah-- Directron didn't seem to have much either.]

Sorry for the trouble. I'll appreciate any suggestions.

 

[alcoholbob]

For 4k;

For cables under 10 feet, you should look at getting a 28awg DP cable.

For runs above 10 feet the only real option right now is DVI Gear's 24 awg DP cables which cost over $100.00. Stardock sells 26 awg cables but they have active 40 pins which makes them useless for 4k.

 

[xthetenth]

Think you mean StarTech not Stardock. Stardock makes games.

 

[Phynaz]

Certified products database:
http://www.displayport.org/products-database/

Myself I've had good luck with StarTech.

 

[Phynaz]

Certified products database:
http://www.displayport.org/products-database/

Myself I've had good luck with StarTech.

 

[therealnickdanger]

The latest standard - that you can buy and use - is 1.2. 1.3 isn't really available on any consumer devices yet, but will use the same cables.

These work great - I have a couple 25-footers.
http://www.amazon.com/Cable-Matters-Gold-Plated-DisplayPort/dp/B005H3Q5E0

 

[BonzaiDuck]

The latest standard - that you can buy and use - is 1.2. 1.3 isn't really available on any consumer devices yet, but will use the same cables.

These work great - I have a couple 25-footers.
http://www.amazon.com/Cable-Matters-Gold-Plated-DisplayPort/dp/B005H3Q5E0

Perfect. I was very harried today, did some more searches just to "get it done" before I came back in here to check. I got confused in all the chaos, and ordered a 10 footer before checking back.

It was the very line of cables at Amazon you linked.

 

[BonzaiDuck]

[That was quite a fortunate coincidence. All the cites and maximum-guaranteeds are there. Hope it is good.]

 

[alcoholbob]

I tried those Cable Matters Amazon cables on several current 4K displays such as the Samsung UD970, LG 31MU97, and Acer B326HK. Since they are 28awg cables you will either not get a signal or get constant flashing on anything more than a 10 foot run.

 

[n0x1ous]

Accell DP cables are certified and have worked perfect for me

 

[cmdrdredd]

I tried those Cable Matters Amazon cables on several current 4K displays such as the Samsung UD970, LG 31MU97, and Acer B326HK. Since they are 28awg cables you will either not get a signal or get constant flashing on anything more than a 10 foot run.

I'd like to see the technical details of why the cable makes a difference.

 

[alcoholbob]

I'd like to see the technical details of why the cable makes a difference.

I don't know what the output voltage is of DP but you can look any website that has graphs on copper wire gauge vs distance, you generally need to go down 2 gauges for every 5 feet of wire. I've been able to run much thinner HDMI cables before signal drops out using the HDMI 2.0 port on my GTX 980 with 4k HDTVs (I got could get a perfect signal with a 20 Ft 28awg cable, and some haze/artifacts with a 25 ft 28 awg HDMI cable) so I've suspected a long time now that DP 1.2 simply has much lower output voltage at the port compared to HDMI 2.0.

 

[therealnickdanger]

The thing to remember is that cable certification/marketing is mostly about extremes. The process is basically like this: "At a length of 100 meters, will this cable transmit the signal needed to still function within a certain tolerance?" Generally speaking, higher quality components, construction, and larger gauge wires will be able to meet or exceed whatever threshold is needed for a given certification. The best thing to do is buy the cheap stuff first and test it. If it works, great! If not, return it and buy something else and test that. It's the most reliable way to know for sure.

Some useful links regarding general cable testing, physics, and snake oil:

http://blog.allion.com/2014/02/alli...-test-report-hdmi-cables-quality-performance/

http://www.reddit.com/r/networking/comments/1w71mh/gigabit_over_cat3_wtf/

http://www.roger-russell.com/wire/wire.htm

 

[BonzaiDuck]

The thing to remember is that cable certification/marketing is mostly about extremes. The process is basically like this: "At a length of 100 meters, will this cable transmit the signal needed to still function within a certain tolerance?" Generally speaking, higher quality components, construction, and larger gauge wires will be able to meet or exceed whatever threshold is needed for a given certification. The best thing to do is buy the cheap stuff first and test it. If it works, great! If not, return it and buy something else and test that. It's the most reliable way to know for sure.

Some useful links regarding general cable testing, physics, and snake oil:

http://blog.allion.com/2014/02/alli...-test-report-hdmi-cables-quality-performance/

http://www.reddit.com/r/networking/comments/1w71mh/gigabit_over_cat3_wtf/

http://www.roger-russell.com/wire/wire.htm

That describes something of my situation. The future-scape suggests either a need for -- or a beginning of -- some upgrade plan for full-HD to UHD.

I think the easiest thing to do is to plan on an earlier purchase of a Display-port 4K-ready KVM switch (without us arguing over whether I "need" a KVM.) I'm currently using a new HD monitor's multi-port switching ability as the video part of any "KVM"-type switching. I can get an idea of how things will work with DisplayPort if I just get a reliable cable. I still wanted to assure that the $10+ purchase would be good much later on, but it's still chump-change.

So after that, what? When should I buy my first 4K desktop monitor? When should I replace my LG LED-LCD HDTV/ Both at once? One at a time? One -- or the other?

In the near-term, I may buy two more cables when I spring with the big-bucks to pay for that Display-port 4K-ready KVM.

Some things may seem unnecessary to others, and "necessary" can be a relative term. In the long run, it's about a $0 investment versus a $200 (sub-4K) investment versus a $430 outlay. The cables, if they don't come up to snuff in that same "long run," aren't of the same magnitude of consequence.

But why not at least try to get one that performs "when the fat lady sings?"

 

[BonzaiDuck]

So I got my wonderful 4K-ready, HDCP-compliant, "high-speed"(???), SIXTY_FREAKIN-HERTZ (only!) DP cable! M***** F****r!!!! G&DD@*#-IT!! And SORRY FOR THAT!!

CHECK THIS, started sometime last fall when the Maxwells were just coming to the buyers:

https://forums.geforce.com/default/...port-with-gtx980-sc-fix-info-posted-11-25-/1/

I can't tell if I need a driver update, when I don't want to mess with the drivers for this sig-rig (and thank the Lord it isn't my SLI rig in other recent threads). I can FIND OUT if I need a driver update, IF I READ THROUGH 31 pages of GeForce Forum Thread!!

Did anybody know about this un-freakin'-pleasant problem? Maybe y'all updated your drivers and forgot about it?!? I won't blame you, but DANG!!

:twisted:

Tonight -- we're going to hook the DVI-HDMI cable back up, and forget this nonsense until we really, really, really want to try it again!

[Typed, updated -- posted -- with a DP connection FINALLY recognized as "Primary Display." Forget about getting into BIOS with this . . . this . . . this . . . . You-know-freakin'-what!!]

 

[Phynaz]

Wut?

 

[BonzaiDuck]

Wut?

My first experience with it prompted the web search revealing the GeForce Forum thread.

My HDTV is connected to a GTX 780 card via HDMI. I decided to try the DP cable for connecting my "primary" Desktop monitor -- until now connected by a DVI-to-HDMI cable (HDMI at the monitor). Right next to the HDMI port on the GTX 780 is a DisplayPort -- port.

AT boot time, the system doesn't recognize the DP connection until after Windows displays the log-in screen on the TV. Changing "primary" monitor to the DP-connected desktop unit leaves the screen blank until the log-in screen.

Not a pleasant prospect for getting into the BIOS here and there as needed.

What the GeForce Forum thread exposes are complaints about the same problem. 31 pages of thread posts.

As much of it as I was able to read, there was speculation that a driver revision was needed to recognize Display-port at system-post time. IF -- it's possible! How would a software driver fix something like that?

I'm skeptical about it. . . .

Once you have your Windows desktop on a monitor like my "desktop" monitor, you discover that (at least with the last-gen GTX 780) your refresh-rate choices are still limited to 60 Hz maximum.

I was looking at DP in anticipation of an expensive DP/USB KVM purchase somewhere down the road.

 

[Phynaz]

Aha, Yeah, I get it now.

My setup has my primary display on DP, and my secondary on DVI. Until the Windows login display it uses the DVI display and the DP display is blank.

I think it's an Nvidia thing as I don't have this behavior on either AMD or Intel graphics.

 

[alcoholbob]

No BIOS display at startup is usually caused by a live 40 pin on a DP cable, aka a non VESA compliant cable

 

[BonzaiDuck]

I think Phynaz may have the more likely explanation.

The GeForce forum thread was an ongoing eruption. His own experience seems to explain with the same consistency what I wouldn't know, for not being an AMD/Radeon user.

Anyway -- $12 and a new DP cable later -- the decision is to put it in the parts locker with the rest of my DVI/HDMI-etc. cables and ponder when and if I get that DP/USB KVM.

For ongoing computer usage, I don't need it. My old Belkin Omni-View KVM is good for the mouse and keyboard, and my monitor can be programmed to make the video switching easy for now.

What I get from all this, however, is that a successful connection via DP only exposes a 60 Hz refresh rate -- no different from HDMI.