From RTings: Anyone seen a cheap cable can achieve chroma 4:4:4 but a good cable cannot?

It's the 15 ft length that is the factor here.

Years ago I wanted to connect my computer to my living room TV for couch gaming and getting 4K 60 Hz 4:4:4 working was an absolute nightmare when the cable needed had to be about 8-10m long. I tried probably 5 different cables before buying a very expensive AudioQuest cable that just worked.

With the other cables - some even claiming to be active, I encountered issues like:
  • 4K not working at all, just blank images.
  • Image going blank randomly.
  • Image flickering.
  • Resolutions and refresh rates randomly disappearing from available resolutions list, not always even the highest 4K option but e.g 1440p @ 60 Hz.
  • No 4:4:4 chroma, only 4:2:0 or randomly 4:2:2 became an option.
You are unlikely to see any of these even with a cheap 3 ft cable.
 
good tips. You would think a website called rtings should know, as they do these tests daily
 
Happy Hopping said:
good tips. You would think a website called rtings should know, as they do these tests daily
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Sadly, they seem to be a little derpy/knowledge deficient in some areas. They are still a great site that I use to check on displays because they do extensive measurements, but I take any conclusions or issues with a grain of salt.

As kasakka says: Length is everything with cables. The shorter the length, the less you have to give a shit about proper construction. Basically the problem cables have is as they get long there is more attenuation and interference at high frequencies, which you have to have better construction/shielding to combat (and even then there's only so much you can do). When they are short, there just isn't enough length for it to really be a problem.
 
their website name is a tongue twister. I can't never remember it properly. But I do like the details tests, like you say
 
is that what that stands for? They could have spell out the entire word, it's not that long
 
I had a short cable problem, the HDMI 6' cable that came with my FO48U could not do 4K 120 HDR, it would just go black on and off. I bought some monoprice 8K cables on Amazon for $19 and it worked perfectly ever since.
 
Some hardware does not like solid cores.
Cheap cables mostly do not have solid cores in their cables.
 
There are multiple generation of redmere cables and have their own specs because they are active cables. As I recall the first generation redmere cables were labled as capable of 4k60 but my experience with them they were only able to pass 4k60 at 8bit for 4:2:2 chroma. I generally avoid monoprice active cables these days because of that experience. Also its not clear on their website which generation of redmere cables they are selling unless you read the info sheets on when they were released, so its very easy to buy an older cable that couldn't do 4k60 4:4:4 properly.

If you are buying an active cable these days I wouldn't even bother with anything that isn't fiber optic, other wise stick with an analog cable with a thick gauge.
 
pippenainteasy said:
If you are buying an active cable these days I wouldn't even bother with anything that isn't fiber optic, other wise stick with an analog cable with a thick gauge.
Click to expand...
Absolutely don't get active cables that aren't fiber optic. The ones that aren't are not really "active" in any useful sense like a signal boost. What they do is they have equalizers in both ends. So they build the cable, then test it and see what the response looks like, they then try to EQ it to respond how it should. Ok neat idea, but with the ultra high signal rates we are dealing with, that isn't going to cut it. The only solutions that would actually work are:

1) Boost the signal voltage. Can't do that, is out of spec.
2) Have a repeater/amp in the middle. Could do that, nobody does because it would be all kind of inconvenient and have problems.
3) Go fiber optic.

It also isn't such a big deal as fiber optic cables are much cheaper these days. They are more than active equalized copper, but not a ton. The 18Gbps ones are actually often CHEAPER. A 50ft Redmere cable is like $60. Amazon will sell you a Amazon Basics 18gbps fiber 50ft for like $40. The actual HDMI 2.1 48Gbps one are more expensive, and I have found that some of them overstate what they can do, like they have issues working at full bandwidth at longer distances, but they DO work and you can get them certified. You can get 20m cables that'll actually work at 4k 120fps 10-bit. I have one right now that does just that. If you wanna go pure fiber optic and just get adapters and run an MPO cable, you can go over 100m with OM5 fiber.

They are also way thinner and easier to run, of course.

These days if passive copper doesn't do the job, fiber is the answer. The "active" copper just is not a good solution.
 
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