How to Tell the Difference Between Display Port 1.2 and 1.4 Cables

Saneche · August 8, 2018

Hey there, this is my first time posting here. I recently built a new rig, and I started to feel like my DP 1.2 cable was holding me back. As far as I can tell from Samsung's limited documentation on specs, my monitor should support 10 BPC color depth and UHD at 3840x2160 (60hz) if I use a DP 1.4 cable. I just got a new cable that was advertised as 1.4 from Amazon, and there hasn't been a difference in my ability to change settings. My monitor still only displays DP 1.2 or 1.1 as options in the settings after plugging in the new cable. I also am still stuck at 8 BPC (changing the setting to 10 in Nvdia control panel always reverts back to 8). The cable was in loose packaging and covered in dust, and I'm beginning to think I may have gotten ripped off with an old 1.2 cable—especially when I noticed that there was a different company name on the cable than the one I bought from. I'm no cable expert, so I don't really know where to go from here other than figuring out how to check if this is actually a Display Port 1.4 cable. I'm running a 1070 ti on a Samsung U28E590DS monitor if it helps.

TLDR: Is there a way to identify what version Display Port cable I received?

Thanks for any help!

Glenwing · August 9, 2018

Just to be clear, DisplayPort cables are not classified by version, they are classified by the amount of bandwidth they can handle.

DisplayPort operates in several modes:

HBR mode is 10.8 Gbit/s

HBR2 mode is 21.6 Gbit/s (introduced in DisplayPort 1.2)

HBR3 mode is 32.4 Gbit/s (introduced in DisplayPort 1.3, still used in DP 1.4)

If the desired video format exceeds the bandwidth provided by one mode, it will have to switch to a higher mode. However, it will not do so unless the cable can handle that amount of bandwidth. HBR2 mode is sufficient for 4K 60 Hz 10 bpc, you do not need a cable rated for HBR3. If the monitor is not providing the option for 10 bpc color then it is not an issue with the cable.

DisplayPort cables are all designed the same way, so there is no difference in physical structure between cables. The differences in the amount of bandwidth they can handle come from manufacturing tolerances. The only way to tell the "difference" is by the certification level, if the cable is certified (not all cables are submitted for certification; it is optional).

"Standard" certified DisplayPort cables are certified for HBR2 mode. "DP8K" certified cables are certified at HBR3 speeds.

Saneche · August 11, 2018

On 8/8/2018 at 8:32 PM, Glenwing said:

Just to be clear, DisplayPort cables are not classified by version, they are classified by the amount of bandwidth they can handle.

DisplayPort operates in several modes:

HBR mode is 10.8 Gbit/s

HBR2 mode is 21.6 Gbit/s (introduced in DisplayPort 1.2)

HBR3 mode is 32.4 Gbit/s (introduced in DisplayPort 1.3, still used in DP 1.4)

If the desired video format exceeds the bandwidth provided by one mode, it will have to switch to a higher mode. However, it will not do so unless the cable can handle that amount of bandwidth. HBR2 mode is sufficient for 4K 60 Hz 10 bpc, you do not need a cable rated for HBR3. If the monitor is not providing the option for 10 bpc color then it is not an issue with the cable.

DisplayPort cables are all designed the same way, so there is no difference in physical structure between cables. The differences in the amount of bandwidth they can handle come from manufacturing tolerances. The only way to tell the "difference" is by the certification level, if the cable is certified (not all cables are submitted for certification; it is optional).

"Standard" certified DisplayPort cables are certified for HBR2 mode. "DP8K" certified cables are certified at HBR3 speeds.

Thanks for your response Glenwing! I was certainly not aware of the nuances between certifications and labeling in regard to DP cables. I appreciate you enlightening me about all this! I see you mentioned that my DP 1.2 cable should be sufficient for the color depth, resolution, and refresh rate that I'm trying to achieve. Is this also true for high dynamic range?

Either way, I am beginning to suspect that someone may have returned this product and stuck in their old cable instead of the one they had bought. I purchased a cable advertised as DP 1.4 / HBR3, and I just want to make sure I got what I paid for since it was twice as expensive as the lower-bandwidth cables. The packaging was a simple ziplock-style bag (that states it is a DP 1.4 cable sold by the company I purchased from, and I fear I may have gotten stuck with someone else's dishonesty or was perhaps misled by the seller. I have never seen so much dust on and inside the connections of a new cable, it has a different company's name written on it, and my computer is acting exactly as it did with the old DP 1.2 / HBR2 cable I had (though this may be expected from what you've told me). A quick google of the writing on the cable suggests that it is a "Hotron DP 1.2 cable", which I assume means it supports up to 21.6 Gbit per second and not 32.4. It is possible that this writing doesn't reflect anything that would specifically identify the cable I have, so I don't know what to make of this. I apologize if I am being dense in lieu of your great explanation, and thanks again for your help!

If it helps, the writing on the cable is: HOTRON - E246588 - AWM - STYLE - 20276 - VW-1 - 80°c - 30v - I/II - A/B - FT1

Glenwing · August 11, 2018

2 minutes ago, Saneche said:

Thanks for your response Glenwing! I was certainly not aware of the nuances between certifications and labeling in regard to DP cables. I appreciate you enlightening me about all this! I see you mentioned that my DP 1.2 cable should be sufficient for the color depth, resolution, and refresh rate that I'm trying to achieve. Is this also true for high dynamic range?

Yes. HDR does not affect the cable requirement, other than indirectly via the fact that HDR requires 10 bpc color depth.

If you are able to select 4K 60 Hz 8 bpc, but not 10 bpc, then this is not a cable issue. Both formats require the system to operate in HBR2 mode, so the cable will be under the same load in either situation. This would indicate some other sort of issue, perhaps in software. I'm not sure if I can help any more than that.

Saneche · August 11, 2018

Sounds good, thanks for your help. Just to clarify, I am able to select 10 BPC in Nvidia control panel, but for some reason, it automatically and immediately reverts back to 8 BPC after applying changes. The same is true for color formats other than RGB limited or full. I am inclined to agree that this seems to be a software issue after your explanation, and I'll mark the thread as solved since it shouldn't matter what bandwidth my DP cable is in regard to my issues. I think I may return this cable anyways, though.. haha.

Thanks for giving me a crash course in DP format, Cheers!