On the unreliability of risers

[VegasBaby]

I thought I'd start a topic about this since they're popular and many of us are getting our first PCIe 4.0 cards even if we're only running them at 3.0 speeds.

I recently purchased a Strix 3090 and it worked great on a PCIe 3.0 riser from EKWB for 2 days before failing to output a display signal. I tried 2 more risers I had, one from CableMod and one from Phanteks and both had the same no display out.

I had the card tested at OCUK and they found no fault and returned it to me. So with that I thought okay lets try a 4.0 rated riser since they'll be more shielded and even though I'm only using the card at 3.0 speed (I'm using a X299 based system that doesn't support 4.0) it should in theory be more reliable.

I received the card back from OCUK and used it on the 4.0 riser and it worked fine for three days until today where it has failed once again to display a signal. I tried seven times to get it to work and even unplugged all power to the system for an hour and still no display out.

At this point I think okay lets give up on these risers and plug the card straight into the top slot on the motherboard. This took some effort as the card is so big I had to move other components in the case to make room but eventually I got it in and hey what ya know, boots right up first time no problem.

This post isn't a troubleshooting post where I'm seeking advice as much as it is a PSA that these risers seem very hit and miss. I was able to use the EK 3.0 riser with a GTX 1080 Ti for over a week without any problem while my Strix 3090 was being tested by OCUK but all four risers I tried with the 3090 were unreliable.

I think that EMI is at play since they seem to work fine for a few days but then fail. The thing is the risers are not damaged and they will work with other lesser cards (Networking cards, that GTX 1080 Ti I mentioned) but not the latest one I have.

I googled the problem and even came a cross a hardware canucks video where he tested around 20 risers and found only 3 to work at 4.0 specifications but he didn't test them extensively it was more in, things work, games run, no crashes etc he didn't run them for multiple days to find out what kind of long-term stability they offer.

For me this has been quite an annoying few weeks but hopefully you all will gain something from my situation. For myself I think I'm going to give up on the risers and keep things horizontally mounted and bonus I can plug in some add-in cards below the GPU now too.

 

[HRL]

My understanding is that PCIE 4 requires short runs to work, therefore risers will always be an issue for PCIE 4.

Probably means the more expensive and better built ones are the only ones likely to be reliable.

 

[VegasBaby]

My understanding is that PCIE 4 requires short runs to work, therefore risers will always be an issue for PCIE 4.

Probably means the more expensive and better built ones are the only ones likely to be reliable.

Indeed that's true. But I was using the card at PCIe 3.0 speeds and still having issues after a few days. I know that many people use them without any kind of problem but I think they're just generally hit or miss, you could install it and have no problem and other times have lots of problems.

For instance the Strix 3090 has a cut out behind the GPU where there is no backplate. I expect the EMI coming out of that small section to be enormous and what goes directly over that cut out when it's vertical? the PCIe riser cable. But on my GTX 1080 Ti that entire rear is completely shielded by a backplate that has no cut outs. And that card? worked fine with the exact same riser cable.

Just thinking out loud here of course I've not got any equipment to measure what kind of electromagnetic interference there could be emitted from the rear of the card.

 

[scubes]

i have a phanteks riser in my setup no problems what so ever!

 

[wookiee87]

i have a linkup gen 4 riser 25cm long (cost £80) and it's been rock solid on my rtx 3090 fe handles my gpu overclock too +100 core and +1000 on the memory, did forget to change my mobo back to gen 3 when i had a ek riser and got into windows but instant black screen, luckly i restarted and got into the bios to change back and it worked, then bough the gen 4 linkup riser istead

 

[Fractured Life]

Linkup seem to be the only ones advertising they've made one and tested it with the new cards, there are a few vids on yt from them now, showing specific cards running.

Assume the other manufacturers will jump on board as there's money to be made, was thinking of one for a 5700 xt - kinda pointless and only for aesthetics but with the USB/Sound/Gen4 issues until the recent fix, was put right off the idea.

 

[FoxEye]

I like the idea of risers in principle, but reading threads like this gives me the impression I'd be paying £100 for a headache waiting to happen.

£100 for a riser is a bit much in the first place, without all the potential issues.

But it would be nice not to have a GPU PCB bending under it's own weight, as well as potential airflow benefits.

 

[dazzlaa]

I’ve been using the lian-li riser kit for about a year now and not once had an issue.

 

[Raiden85]

I had a Phanteks premium riser cable for the 2080 Ti that worked flawlessly in a Z370 chipset and X570 in gen 3, but with my Strix 3090 OC on X570 it actually booted once in gen 4 then never did again for some reason, just a black screen with the motherboard complaining about a missing GPU permanently.

Picked up the linkup PCIe 4.0 riser and that booted and ran completely flawlessly with my 3090 in gen 4 mode, PCIe 4.0 needs a much higher quality riser and there is very few it seems out there at the moment, the linkup one seems to be a very good one and the build quality on it is very good but does come at a cost.

 

[Grim5]

My understanding is that PCIE 4 requires short runs to work, therefore risers will always be an issue for PCIE 4.

Probably means the more expensive and better built ones are the only ones likely to be reliable.

This type of thing will continue to be an issue as we push for higher and higher bandwidth, well run into more issues with copper based traces

the entire motherboard needs to move to digital signalling with fibre optics

 

[HRL]

Fricking lasers!!!!!11

Silicon photonics. Just ask Intel, they’ve spent 20 years working on this already.

 

[heartburnron]

I had my 6900 XT running with the ROG riser cable for a couple of weeks (then I put it back horizontally as it just looked too in your face for me). It occasionally didn't post a signal on boot up when I left the pcie gen setting at auto in the bios, however after manually changing this to pcie gen 3 I had no issues what so ever.