Weeks after Nvidia announced it was investigating reports that the power cables for its RTX 4090 graphics card were melting and burning, the company says it may know why: they just weren’t connected all the way.

In a post on the customer support forum on Friday, Nvidia says it is still investigating the reports, but that the findings “suggest” that an insecure connector is a common problem. It also says it has received about 50 reports of the issue.

Nvidia’s flagship card uses what’s called a 12VHPWR power connector, a new standard that isn’t natively supported by most power supplies people already have in their PCs. That’s why an adapter – or “power dongle,” as Friday’s post calls it – comes in the box. Initial reports from users blamed the adapter, with some saying the melting cable also damaged their $1,599 GPU.

It could be easy to read the company’s findings as blaming users. Of course, Nvidia won’t come out right away and say that it’s user error, but it’s heavily implied in the post. It also seems like a very useful explanation, since people have been speculating for almost a month that the problem is caused by something more complex, such as poor soldering or wires that are too small to reliably handle the massive amounts of current being pumped through them.

However, GamersNexus, an outlet respected in the PC building community for its rigorous testing, came to essentially the same conclusion earlier this week. A video posted by the outlet on Wednesdaywho inspected damaged adapters submitted by viewers and extensively tested and reported on the problem showed that the connectors had wear lines, implying they were not fully inserted into the slot. GamersNexus even says that some people seem to have missed a full connection by a few millimeters. The video shows that a loose connection can cause the plug to heat up dramatically, if it’s poorly connected and tilted at an angle.

Nvidia’s post includes an image of what the connector looks like when not fully plugged in, and it seems much easier to miss than something sticking out a full 2mm and held at an angle (possibly because the cables are pulled back too tight) . during installation). It would be even easier to miss with a third-party RTX 4090 card instead of the Nvidia version shown in the images below.

If you have one of these cards in your computer, you should probably double check that your card looks like the bottom one.

However, it’s worth noting that Nvidia may not be fully innocent here. Another thing to note about the posted photo is that the connector has a locking key. In theory, that’s a feature that would prevent this sort of thing, as long as it gives good feedback when you plug it in. According to GamersNexushowever, the adapters don’t actually click into place audibly, even when fully inserted.

Aside from that, the tests done by Nvidia and GamersNexus don’t seem to point to manufacturing defects as the main culprit (the outlet’s video on Wednesday did say debris left behind during production may have been an aggravating factor). Anyway, an unnamed spokesperson for the company told GamersNexus on Friday that “any issues with the burned cable or GPU, regardless of the cable or GPU, will be processed” for a replacement.