pci sensor 127C


New Member
Mar 23, 2018
Dear people,

I have real problem with alienware x51r3. my pci sensor is 127C and when i remove graphics card it start working. Problem is that pci sensor is overheating, but i dont know how to stop it. If graphics card is in, computer is not starting. fan is going crazy at start and nothing will go on. How can i fix it? or this is a dead pci sensor?


May 11, 2018
It's been a while since you've posted this, but in case you are still needing info or help, I'll pass on a few observations :)
1) I've only had my x51 for about 2 months, but it always reads 127c on the pci sensor in the *thermal controls* panel.
I *think* this must be a bug, because 127c/260f is pretty dang HOT, and I'm pretty sure my system would have already melted down long ago if that sensor reading was correct.
So I would suggest finding a 3rd party utility to double check your sensors. I used a trial version of Aida64 to check mine. in aida64, if i expand the "Computer" category, and then select "sensor", it shows me 10 sensor readings, and none of them are over 42c. (I would *not* suggest running the thermal control panel thingies at the same time as using another sensor polling program. I don't know about these systems, but in the "old days" trying to run 2 or more programs to poll the same sensors could cause some really screwed up readings. you can try it if you want, i just "figure better safe than sorry".)
Now, in aida, there is no sensor labeled "PCI", so I don't know for sure if it's actually reading the same sensor, or not, or why it shows so many sensors compared to the thermal control panel. I can only say that in aida, and any other 3rd party programs i've used to read sensors on my x51, I've never seen any reading anywhere near 127c. I've only ever seen that reading in the alienware thermal control panel.
2) On my x51, if I attempt ANY kind of manual fan control settings, *ALL OF MY FANS WILL SHUT DOWN AND THE PC SUDDENLY HEATS UP LIKE CHERNOBYL!!!*. resetting the fans to the automatic defaults made them work again, but because I've experienced that bug, I don't recommend messing with the fan controls in the alienware control panel.
3) your power fan shows zero/0 rpm. Mine reads 2448 rpm right now. I don't think it should *ever* read zero. So I think you should check to make sure that your power fan is plugged in, is actually spinning, and doesn't have any cables or anything blocking it from turning when you put everything together.
I *think* that the power fan is the little fan over the heatsink that is attached to the power distribution board, which is behind/under the optical drive tray. (if your system doesn't have that tray, then it's the board to the right of the motherboard. the motherboard's 24 pin connects to it, and it has the power connections for things like sata drives and pcie 6-pin (for connecting to the video card if needed).
4) If your system won't start with a video card installed, you might want to make sure that the pcie 6-pin cable is attached to the card on one end, and the power distribution board on the other. that is, if your card has a 6 pin plug on it for drawing extra power. my card is a gtx 1080 that has an 8-pin pcie plug, so I ended up using an 8 pin to dual 6-pin adapter cable and then hooking that to the x51's 6-pin to dual 6-pin cable (pretty sure the original cable is just a Y-splitter, but I didn't look close) so the way mine is hooked up right now is pretty dorky, and I'll eventually pick up a 6 to 8 pin pcie video card cable, and do away with all that mess of extra wires. but anyway, the space for wiring is really tight under that optical drive tray and that's where that little power fan is, so you have to be careful no wires end up blocking the fan when squishing everything back together. Plus, at least on my x51, some of the plugs were pretty loose where they attach to that board. So it's something to keep in mind.
Anyway, don't know if any of that helps or not, but hope things turn/turned out well for ya :)
Likes: revchamp440
Jul 26, 2016
I have X51 R2 and SpeedFan shows -128 degrees on Temp3 sensor, but Argus Monitor shows nothing at all.. I believe this means that there is in fact no temperature sensor on board in my case. But if you have issues with computer and it's not starting, that may be a different situation. What graphics card do you have? Original from Alienware or something else you have purchased?
May 11, 2018
As a sort of an update to the reply I posted before; My r3 came with the basic air cooler and the pci-e riser card that didn't have the ssd slot (m.2 slot i think?), so i installed one with the slot that I bought on ebay, and a used water cooler, and I stopped getting that crazy high pci sensor reading. it currently is reading 33-34 celcius, which is the same temp i'm getting from the power, gpu and vrm sensors as well. I would assume it must have been changing the pci-e riser card, but the water cooler runs off a different plug on the board than the air cooler did and i made both changes at the same time, so I couldn't rule that out as a potential factor. (unless I took it all apart again and changed parts back and forth, which wouldn't be much fun with the way things are packed in there)
I also ended updating the bios and a couple of other things, but i'm pretty sure that was after seeing the change, so probably not a factor. my assumption is that it's some sort of glitch with the non ssd-slotted riser, but I haven't confirmed it.