Widescreen Gaming Forum

Yeah. It threw me off completely to find that the cable was causing the issue. Especially after it worked fine for so long. It reminds me of that time that I was having trouble getting Windows XP on a friend's machine, and it turned out that the DVD drive had an issue. It would install sometimes just fine, but BSoD on first reboot. Sometimes it would BSoD during the installation. Windows 2000 would install and boot just fine. So, I figured the DVD drive didn't have any issues, as I could get other operating systems to install, including Ubuntu. It took the better half of a year before finally figuring out it was the drive that had an issue. Gutted one from another system to do the install and it was fine after that. Ugh.. Windows...

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Long one lurker first time poster...

With that out of the way.

Bad DP cables have been giving me issues for months now. I figured out the why though.

If you read the VESA Displayport standard it states.
Here on page 147

3.2.2 DP_PWR Wire

A standard DisplayPort cable must have no wire for the DP_PWR pin.
Only captive cables supplied with cable powered Branch Devices or cables permanently attached to Sink
Devices are permitted to have the wire for DP_PWR. These captive/attached cables must have a standard
DisplayPort plug connector (as specified in Section 4.2.1) on one end only. The other end must either be
permanently attached or have a custom connector.

If you look at the pin out for a DP cable.

Pin out

External connector (source-side) on PCB
Pin 1 ML_Lane 0 (p) Lane 0 (positive)
Pin 2 GND Ground
Pin 3 ML_Lane 0 (n) Lane 0 (negative)
Pin 4 ML_Lane 1 (p) Lane 1 (positive)
Pin 5 GND Ground
Pin 6 ML_Lane 1 (n) Lane 1 (negative)
Pin 7 ML_Lane 2 (p) Lane 2 (positive)
Pin 8 GND Ground
Pin 9 ML_Lane 2 (n) Lane 2 (negative)
Pin 10 ML_Lane 3 (p) Lane 3 (positive)
Pin 11 GND Ground
Pin 12 ML_Lane 3 (n) Lane 3 (negative)
Pin 13 CONFIG1 connected to Ground1)
Pin 14 CONFIG2 connected to Ground1)
Pin 15 AUX CH (p) Auxiliary Channel (positive)
Pin 16 GND Ground
Pin 17 AUX CH (n) Auxiliary Channel (negative)
Pin 18 Hot Plug Hot Plug Detect
Pin 19 Return Return for Power
Pin 20 DP_PWR Power for connector (3.3 V 500 mA)

On a standard Displayport cable being used to hook up monitor to video card.
Pin 20 DP_PWR Power should not be connected. It is back feeding 3.3v back into the video card causing all kinds of issues. A lot of company are pushing out products that are not following the correct VESA Displayport Standards.

I tested this by removing my video card and connecting Displayport cables. These are Monster Digital Life cable.




Measured here from negative lead on meter to screw on back of card.



And Reading 3.3v on video card. (MSI 7970 reference card)



Just some info a thought I would share. I am still lookig for some good cables. I am open to suggestions.

On a standard Displayport cable being used to hook up monitor to video card.
Pin 20 DP_PWR Power should not be connected. It is back feeding 3.3v back into the video card causing all kinds of issues. A lot of company are pushing out products that are not following the correct VESA Displayport Standards.

Ehm, the Monitors gives 3.3V BACK into the GPU?

Isn't the GPU supposed to give 3.3V Out to any adapter you might plug in ?

Verry interesting find! Thx a lot! Gotta test that with my two miniDP->DP cables!

P.S Any means to contact AMD and ask if they have any idea what this 3.3V input might cause?

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I am unsure what kind of effect the 3.3v has had on the card/cards. I am getting system freezes though while playing sniper elite v2 still even after getting some compliant cables. Using the non compliant cable I was getting image frozen and buzzing/sound were only cycling power will reset my system on a lot more games. I am unsure if this is a driver issue with running eyefinity and trifire 7970 or if the cards are damaged. I am going to wait for the next official driver from AMD to see if this issue is fixed if not then I am going to RMA the cards one by one.

The cables I found to be compliant are Belkin Displayport Male to Displayport Male. I did away with using the Mini-DP to DP cables and am using the Mini-DP to DP female dongle that was included with my MSI reference 7970's.

Here is a link to the compliant cables. Hope they help someone out.
http://www.amazon.com/gp/aw/cr/B0017U61M8/ref=aw_d_cr_electronics

The cables I found to be non compliant were startech.com Mini-DP to DP I got from amazon.
Monster Digital Life Mini-DP to DP cable.
I tested 2 cables from both manufactures.
I am running one DVI and 2 displayport connections for 3x1 eyefinity.
Using 2x ASUS VE278Q, 1x ASUS VK278Q monitors.

As for you question isn't the card suppose to supply 3.3v. I don't think that is the case if you read the spec only place 3.3v is pin 20 and that is not suppose to be used connecting monitor to video card. It is only suppose to be used for powered branch devices or cables permanently attached to sink
devices.

Well yeah -.- a lot of people using Crossfire get unwanted Freezes ingame when playing for a long time (me included)




So if the Card does not output any voltage via miniDP, how do these "Active miniDP->DVI" adapter work which have no USB powered? does the DVI cable from the Monitor comes with energy?

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I have not used any adapters but if you are talking about the ones AMD announced that are active and don't need USB power here is some info..

eyefinity requires an "active" cable, because the conversion from DP to DVI or HDMI requires additional power if you want to use larger resolutions. Most active cables had a separate usb plug that needed to be plugged into your pc for the cable to work. The new AMD adapters have a new decoder chip that doesn't require as much power, so no additional usb plug is necessary:

"Internally the new cable uses a single piece of silicon with a DispalyPort decode and a TMDS for the DVI output. This greatly reduces the power requirement (hence the reason no additional power is needed) and should also eliminate the flicker issue that is prominent with the powered Dual-Link adapters."

So I am reading this as the adapter gets enough power from the DP signal that it does not require additional power.

List of official supported DP cabels.
http://www.displayport.org/products-dat ... ufacturer=






http://www.displayport.org/cables/how-t ... a-bad-one/

so they do know about that problem!

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We gonna send it to outa space!

Sorry for bumping old thread, but this may be a problem I'm having too. I get these lines/static when using DP on my GPU, but when I use HDMI, the lines disappear. I have used the same DP port and cable before, but after a BSOD these lines started happening. Is it because of a bad DP cable? I was just using the DP cable that came with my monitor.

New member and first post here

I'm thinking a bad DisplayPort cable could be my issue...

Since Nov of 2013, I've had 3 Galaxy nVidia 780 cards fail ( don't have a great track record based on many forum posts), or so I thought. The last one failed last weekend, and that's when I started to think that it was my power supply. (Corsair HX850). I finally brought my comp to a local tech guy. Just called, and they said they ran a full diagnostic and the computer is working fine... What the f***.

I do remember that the DisplayPort cable is quite hard to insert and remove from the port on the video card....

What do you folks think?

My system...
*Asus P8P67 Deluxe MB w/ latest bios
*Intel i7-2600k (never OC'd)
*Galaxy nVidia 780 (never OC'd)
*8 GB Corsair Vengeance
*Xonar Essence ST sound card (internal)
*Intel x25 SSD
*Corsair HX850 PS
Eizo FG2421 monitor
*Win 7 pro 64bit OS