GTX 970 owners. VGA test.

[Iceni]

I'm having an issue with both of the GTX 970's I got.

I didn't notice it at first but when using a VGA cable with the DVI adapter I'm getting a dirty signal on both cards on 2 different rigs.

If anyone can test their cards in the same mode I would be appreciative.



The test is simple. Just use a standard VGA cable to your monitor and a DVI adapter.

You are looking for the effect in this video. It will only happen on GPU demanding games and some benchmarks.

Unigine haven causes it but it's hard to spot. Warthunder and FC4 cause it all the time.

I have tried the suggested fix on that video's comments, No dice.

So I'll be buying adapters to move over to digital output. (my cards only have mini HDMI, Mini DP, and Dsub) So I had to use the DVI adapter to get the cards working on both rigs. Adapters are on order but I wanted to see if the problem was universal.

If it is universal then perhaps Wizzard or someone like can do an article on it since there are still a lot of VGA only monitors at 1080p out there.

 

[newtekie1]

Yeah, just use DVI...no one should be using VGA with high end cards anymore, VGA is extremely prone to EMI interference, which is what you are seeing.

 

[Iceni]

Yeah, just use DVI...

My monitors only have VGA and HDMI in. So I need the mini DP adapters or mini HDMI to regular HDMI adapters. I don't think it's going to be an issue for me, but for it to be happening on 2 different rigs both with these cards I think It warrants been looked at.

The other rig is:

1055T, AM3+ asus, 8GB DDR3 corsair, Palit 970.

Both rigs have different brand PSU's, Mine is the FSP, the other rig is a Seasonic.

I'm thinking the Signal convertor is sub par on the card. I did notice that it squeals a bit when up close, and the rate of squeal is almost in time to the flickering.

I think the card itself is the reason for the interference, I'm suspecting a noisy DA convertor. I want to know if it's a Palit specific problem, Or something universal. I can still send these cards back if it's Palit specific.

 

[newtekie1]

It isn't the signal converter, it is just that the VGA traces on the card are receiving interference from the card's power circuits. That is why the problem is worse when the card is under load, there is more power running through the power circuits so they are putting out more interference. It is a common problem with VGA, all of my APU rigs as well as my onboard Intel from my 4790K do it too. I think the layout of the cards is likely one of the reasons you are noticing the problem more on the 970. Most 970s have the VRMs at the front of the card, between the GPU and the outputs. Most other cards are laid out with the VRM at the back of the card and the GPU has a direct shot to the outputs.

If your monitor only has HDMI, either do what you said and use the mini-HDMI adapters or use DVI to HDMI adapter. Personally, I'd just return the cards for ones that have a full size HDMI.

 

[Eric_Cartman]

I don't know about the 970 but I can tell you my 670 does the exact same thing with VGA.

 

[Iceni]

Awesome so it's definatly not a fault then

I managed to dig out an old DVI-i>hdmi cable and the monitor is now running without fault. It's also solved the minor coil whine it had. Those D/A convertors or shielding must be really cheap on these cards. I've never seen a card do this before.

I'm going to pick up a couple of adapters for the other monitor and I should be back in business with the dual screens for work.

 

[newtekie1]

Those D/A convertors or shielding must be really cheap on these cards. I've never seen a card do this before.

I don't think the shielding or D/A converters are cheap, I think it is completely down to the fact that the analog signal has to pass right through the VRM on the card. They probably didn't really think this would be a problem since they don't really expect many people to be using VGA with high end cards like these. And I wouldn't be surprised if see the next generation of cards do away with VGA completely.

 

[Mussels]

this happens a lot on modern cards, from what i've been seeing its more common with nvidia but the cause is the same - VGA is something of a dead standard, so support is somewhat lacking.


Its annoying that a supported connector/advertised feature has problems like this, but since just about everything had HDMI or DVI, its not the end of the world.

In theory a powered DP->VGA adaptor would bypass these issues and provide a stable signal as well.

 

[gelittenberg]

its a crappy dvi to vga adapter. ive tried my old dvi to hdmi from zotac (with a hdmi to vga converter) and the "effect" was gone

 

[eidairaman1]

I don't think the shielding or D/A converters are cheap, I think it is completely down to the fact that the analog signal has to pass right through the VRM on the card. They probably didn't really think this would be a problem since they don't really expect many people to be using VGA with high end cards like these. And I wouldn't be surprised if see the next generation of cards do away with VGA completely.

Im using dp to vga adapter. See my sig for the specs. It was made by startech. Once i rewrote xp drivers gor 7 64bit no issues.

 

[Iceni]

its a crappy dvi to vga adapter. ive tried my old dvi to hdmi from zotac (with a hdmi to vga converter) and the "effect" was gone

I actually tried 4 different adapters. Same problem on all.

1 was from an ati 9700 pro, one from an hd6950 sapphire, One shop bought and the last one was from Palit. I tend to keep cables and trinkets in a big box together.

The cable did not have a ferrite block on it and that may have helped with the banding. Old VGA cables tended to have those blocks and I'm leaning towards that been a contributing factor.

The only thing I didn't do was check with my non IPS monitor. My son's monitor isn't IPS tho so that can't be the fault.

Moving to digital has solved it 100%. I've not had a single blip out of place since the swap.