Question Possible issue with new power supply

JayGau

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A month ago I changed my four years old Corsair CX650M for a brand new Corsair RM750x because with all the stuff I constantly add and the new RTX 3000 cards that are coming I thought it was time to get some more power (but my 650W was still doing all right). I chose the RM750x because it's rated as one of the best PSU on the market.

However, a few days after I installed it my PC rebooted by itself during gaming. Before to send back the PSU just for an isolated event I decided to wait and nothing else happened until this week. Three days ago when the PC woke up from sleep my RGB settings where all messed up and yesterday it did it again but it was even worse since my keyboard and my mouse were off (like not powered). I unplugged and plugged back a random USB cable from the Motherboard and strangely enough things came back but I add to set my Aura settings again.

And this morning the PC rebooted by itself again but this time it got frozen at the "press F2 to enter BIOS" screen so I had to hard reboot it with the power button. But when the reboot happened I saw that the lights in the house went down for a very short moment, like a spark. Was the reboot causing a power down of the power down caused the reboot I don't know.

But I read online that if you have a high rated PSU from a well known brand this kind of issues are almost never caused by the power supply but I find it very strange that they started just after I insatlled it. Any thought?
 

PC Tailor

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from a well known brand this kind of issues are almost never caused by the power supply
Not necessarily, defects still happen. No process is perfect. Yes it's certainly far less likely, but it still happens. Put it this way, if it was a poor quality PSU, it's almost inevitable it's the PSU. If it's a good quality one, it's possible, just less much less likely to be the thing you point the finger at.

Presumably you still have the CX?
Have you absolutely verified everything is properly connected?

Worst case, put the CX back in, see if the issue goes away, and if it does, RMA the unit and they will send a new one. The RMx is a fantastic unit, but defects do and will still happen ultimately.
 
Make sure all your connections from the PSU and motherboard and connected firmly. It is suspicious but to fully confirm it's the NEW PSU's fault can you try re-installing your OLD PSU and see if you're having the same issues? This way you will be able to determine if the NEW PSU is at fault or if there's something happening with your motherboard (Always a possibility it got damaged during installation of the new PSU).
 

JayGau

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Thank you very much for the replies I appreciate it!

First of all, about the cables I am confident that they are all well and firmly plugged. I think we can rule that out.

Another thing that I did a few days before I replaced the PSU was to add 16GB of RAM so now I have 4x8GB but I ran Prime95 for 2 hours a couple of weeks ago and everything went fine without any errors so it doesn't look like a stability issue.

I already thought about putting back the CX650 to see if the new one is faulty but there was two problems: first it's a pain in the neck to do and secondly the problem was not happening very often (I had 3 weeks without any issues) so if I put back the CX how long do I have to wait to make sure it's working fine if the new one crashed only twice in a month?

But now that problems seem to happen every 2 or 3 days it might worth to try to put back the old one. I think I gonna wait a couple of days and see if the problem happens on a more regular basis. If it does then I have a more suitable situation where I can put back the CX and see if it's doing better. If it's still bad then it's something related to my board (or the RAM), otherwise it's the PSU and I can request a replacement from Corsair.
 

Juular

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What's your system specs to start with ? If it's Ryzen, then reboots can be explained by your motherboard / it's UEFI and your RAM not working well together, you can try to lower RAM frequency and/or update UEFI.
 

Vic 40

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Another thing that I did a few days before I replaced the PSU was to add 16GB of RAM so now I have 4x8GB but I ran Prime95 for 2 hours a couple of weeks ago and everything went fine without any errors so it doesn't look like a stability issue.
Besides testing with the old psu also test with the added ram removed. Do a clear cmos after it and reenableXMP/A-XMP/DOCP.
 

JayGau

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Here are my specs:

Ryzen 3700x
Asus Rog Crosshair Hero VII
Corsair Vengeance RGB pro CMW16GX4M2C3200C14 4x 8GB (running at 3600 MHz CL16)
EVGA RTX 2080 XC Ultra
Samsung 970 EVO Plus 1TB NVMe
Corsair RM750x PSU

For the clear CMOS it was a good thought but it's actually the first thing I did after I installed the new PSU a month ago. And right after the first reboot I also did a BIOS update just to make sure. I thought the problem was solve since after that I didn't have any problem for three weeks but looks like it's not.

My RAM has always been stable at this speed for more than a year (even at 3700MHz but I lowered it to 3600MHz after I added the extra 16GB and anyways ASUS screwed up the FCLK for higher frequencies than 1800Mhz with their recent bios updates). This RAM is also very expensive (200$ for a 16GB kit) and uses Samsung B-Die so I have a hard time to believe it cannot run at 3600 MHz CL16 with a Ryzen 3700x. And my successful 2 hours test with Prime95 seems to confirm it can. One thing I could try is to increase the RAM voltage a little. I currently run it at 1.37V and I could try 1.38V and see if the reboots stop, but I really doubt it's a RAM issue.

There is also this kitchen light flash that I saw yesterday when the computer rebooted that is still puzzling me. I mean, the house lights don't usually flash when I reboot the computer so why it did that yesterday? If It's a power issue then I could understand but if it's just some RAM stability issues it would have nothing to do with the house power so why the lights went down? I forgot to mention it but I was not gaming or doing anything with the computer when it rebooted yesterday I was not even in the computer room. I know the light flash happened at the same time because my computer room is just next to the kitchen and I heard my fan spinning like they always do when the PC reboot right after the light when down. A good power supply should be able to keep up with a short house power decrease isn't it?
 

Vic 40

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A good power supply should be able to keep up with a short house power decrease isn't it?
Depends how long it lasts. An UPS might be a good thing for you if this might happen more.

Mixing ram can still be a source of problems. It's up to you to test or not. Kits exist so maufacturers can be certain that the stick in such a kit will work together for sure, adding ram,even "exactly the same", for which they cannot say for sure it works with the original sticks might introduce variables that give issues.
 

JayGau

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Yes I indeed started to look for a UPS yesterday but the good ones are in the range of 100$ and if the problem is with the PSU and not with the power in the house then the reboots would still happen. But I guess it's a nice device to have anyway so I might order one and if the reboots stop then I would know what was the issue.

About the RAM, I read that the only difference that can happen between two "same kits" is that the vendors can use parts from different manufacturers even if it's the same model and the only way to be sure they are exactly the same is to buy your sticks in a kit. But people also say on forums that if you are willing to try anyway and they work fine then you are good. Mine are working very well even overclocked at 3600MHz CL16 and are still holding 1T. AIDA64 benchmark also gives me very good numbers and as I already said, Prime95 can run for 2 hours non stop without any errors or crash. It's why I doubt my RAM is the issue but if you have some other ways I don't know to test it even more I will try for sure.
 

JayGau

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Yeah I see your point. Better to make sure before to rule that out. I ran memtest86 tonight. I did only 2 passes because it takes almost 90 minutes per pass and I needed my computer but I got 0 errors. This in combination with the successful Prime95 test makes me believe that my RAM is ok.
 

Vic 40

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There is also this kitchen light flash that I saw yesterday when the computer rebooted that is still puzzling me. I mean, the house lights don't usually flash when I reboot the computer so why it did that yesterday?
Don't think the psu causes this, maybe just the extra load the pc gives/takes. Might mean you don't have great wiring in the house or fusebox isn't great don't know. Think that adding an ups might help, not really into those since we really don't need them here.
 

JayGau

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I will receive the ups on Friday and see if it helps with the reboots. If I get another reboot event after that then I gonna have to suspect the psu again (but either way this ups has surge protection and 12 outlets so it will be much better than the cheap power bar I currently use).

About the things that are sometime messed up after the computer wakes up from sleep, I may have solved that. I am not 100% sure but since this problem seems to be related to the usb controller, I decided to plug my monitor led strip into the wall instead of the computer usb port. This led strip was generating some noise in my speakers and last time I got this problem, unplugging it brought back my keyboard and mouse power as well as my iCUE controlled RGB (but I still had to set back my 12V Aura settings, as I said in my first post). By the way this problem started before I changed the psu but became worse a few days ago (never lost mouse and keyboard power before). Maybe this led strip is draining too much current, what was doing some bad to the MB. Now that it's plugged into the wall I no longer hear this noise in my speaker so maybe this wake up issue will not happen again either. But I did this before the last reboot so for sure the strip was not related to this particular issue.

However, if one or both problems still happen after I get the ups and with the led strip plugged into the wall then I will have to put back the CX650 and see if things get better.
 

Vic 40

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I will receive the ups on Friday and see if it helps with the reboots. If I get another reboot event after that then I gonna have to suspect the psu again (but either way this ups has surge protection and 12 outlets so it will be much better than the cheap power bar I currently use).
Hope the UPS will help with reboots.



About the things that are sometime messed up after the computer wakes up from sleep, I may have solved that. I am not 100% sure but since this problem seems to be related to the usb controller, I decided to plug my monitor led strip into the wall instead of the computer usb port. This led strip was generating some noise in my speakers and last time I got this problem, unplugging it brought back my keyboard and mouse power as well as my iCUE controlled RGB (but I still had to set back my 12V Aura settings, as I said in my first post). By the way this problem started before I changed the psu but became worse a few days ago (never lost mouse and keyboard power before). Maybe this led strip is draining too much current, what was doing some bad to the MB. Now that it's plugged into the wall I no longer hear this noise in my speaker so maybe this wake up issue will not happen again either. But I did this before the last reboot so for sure the strip was not related to this particular issue.
That is good to hear and good to know of.
 

JayGau

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Just to give an update, I cancelled the UPS order. I read that to be safe, efficient and fast to respond with recent PSU models (that use active PFC) they have to generate pure sine waveform output and those are 200$ and above for the power I need. It's kind of expensive for something that might not even solve the problem.

By the way, I got a third reboot event yesterday a minute after I turned on the computer. Everything seemed to be just fine, I Iogged into Windows, my iCUE settings turned on and a few seconds later boom... reboot. And nothing was wrong with the power in the house. So I put more voltage on my ram and if it still reboots I will have to put back my old PSU to see if it's related to that.

I also got another Keyboard/12V led power issue during the weekend so it was not my monitor led strip after all. I noticed this time that it happens when I unplug my mouse: I prefer it wireless when I game but I have to charge it regularly so I plug it in the morning to have it charged when gaming time comes in the evening and this issue seems to happen when I pull out the mouse usb cable at night (but not all the time, I do that every day and this happens maybe once a week). I have a hard time to figure out how this could be PSU related. I pass from wired mouse to wireless mouse the PSU should not even notice it. That's very strange.
 

JayGau

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I was waiting to see if the issue was happening more often before to put back the old PSU because if it happens once a month it's not easy to test. But since it seems to happen about once a week now I might want to put back the old PSU soon and see if it stops.

I didn't use any of the CX650 cables when I installed the RMx (I didn't want to fry anything with a non-compatible cable). I only used the ones that came with the new PSU.

Yes I installed the "Version 3103" just after the first reboot event.

I have a lot of USB powered devices but none of them are odd. I have mouse, keyboard, Corsair RGB mousepad, Corsair LT100 RGB towers (those have their own power in the wall but are controlled through USB), my bluetooth dongle for my headphones and my Line 6 GX USB sound controller. I also have the Corsair Commander pro that is connected to the internal USB 2.0 header and I use the Commander pro to daisy chain my Corsair H150i PRO XT CPU cooler USB 2.0 connection (it's a shame that a so expensive motherboard has only one USB 2.0 internal header).
 
After reading your first post, I thought it was your motherboard.

Now that I see that you've also upgraded your RAM, I'd say it's your RAM. Take the extra 16GB back out.

As for the UPS needing to be pure-sine. That is complete B.S. and is only true with old and/or cheap topology PSUs. MOST people with UPS's on their PC's are only using simulated step sine wave UPSs.
 

JayGau

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That would be an easy test to do (much easier than replacing the PSU) but I have some new info that might rule out the RAM.

With your advice you gave me another idea that I just tested. Before I added the extra 16GB I was running this ram at 3733MHz but with the extra kit it doesn't even boot at that frequency and I had to lower it to 3600MHz. So tonight I removed the new 16GB kit and overclocked my old kit to 3733MHz as I was running before. It worked without any problem. So I removed it and put the new 16GB kit instead and tried to boot with the 3733MHz still set. It also booted without any problem. So I put back the other kit and it didn't boot as usual so I had to go back to 3600MHz. So it means that the new kit can be overclocked like the other one and it's really when they are both installed that I cannot reach the 3733MHz. That means that if they really cause problems only when are together I will have a very hard time to convince Corsair to take it back and it's a 200$ kit.

But there is something new that started to happen yesterday: when I boot and get to the Windows login screen my monitor gets black and my RGB devices inside the case turn off for like 1 second and then everything comes back to normal and I can login. It never did that before and guess what... It also did it when I had only the old RAM kit installed during my overclock test tonight so it's not caused by my new RAM kit. I feel like everything is slowly falling apart and that started with the new power supply. I think I will try to find a moment during the weekend to put back the old one and see if those things go away.
 

JayGau

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I am using a Ryzen 3700x which is well known to work better with high RAM frequency. AMD recommends 3600MHz for this CPU. I have been running this RAM at 3733MHz for a year without any issue until I added the new 16GB kit and changed the PSU. And beside those rare reboots (3 in almost two months now) the PC is running extremely well and it's very fast so I doubt my CPU cannot handle my ram speed. And I ran a Aida64 test for an hour yesterday and everything went well: no crash, no error and my CPU temp stayed below 70C.

By the way the black screen I had yesterday was most likely because of a Nvidia driver I installed this week. They released another one a few days after that (it's suspicious that they released two drivers in a so short period of time) so I installed it yesterday night and this issue went away (so far). For my RGB stuff flashing at the login screen, without the black screen it looks much more familiar and normal (I think it's just the Corsair software that is initializing). I have the habit of becoming paranoid when my machine has a problem and I exaggerate every little things like my computer is going to die even when it's normal behavior.

I think I have a plan: I will wait to see if I get another reboot this week (would mean that increasing the RAM voltage to 1.38V didn't solve the issue). If I do I will take out the new RAM kit and wait for let's say 3-4 weeks. If I don't have any reboot I will switch the old kit with the new one and do the same. If I don't have reboots I will run with both kits and see if the reboots come back. If they do it's because those two kits together cannot run perfectly stable at 3600MHz. And if I have a reboot during the first 3 weeks (with the old RAM kit only) then it would mean that it has nothing to do with the RAM and I could try to do the test with my old PSU.

Does it sound good?
 

JayGau

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Three weeks without any reboots now and I still have the 750W PSU and both RAM kits in (still running at 3600MHz CL16). So maybe increasing the RAM voltage was the right thing to do. By the way, just after my last message I followed Vic 40 advice and put 1.4 V instead of 1.38 V. Maybe that helped too. Let's see if it stays like that. I would like to wait for a full month without any reboot events before to say the problem might be solved.
 
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