Problem with 3090 FTW3 / RM850x combo and possible replacement advice

McEgan · April 30, 2021

I'm running a 9900k / 3090 FTW3 Ultra / RM850x combo, and 99% of the time I have no apparent issues. Rarely though (sometimes the issue will not manifest even during 24 hour runs of Furmark or Ethereum mining, and sometimes it will take only an hour when playing a game with unlocked FPS), and only ever at absolute peak loads, will my PC suddenly shutdown and restart itself. Even rarer is sometimes it won't restart, but will simply give me a black screen and the GPU fan will kick up to 100% and will stay like that until I manually restart. This is with the 9900k at stock, and the FTW3 at its "stock" (whatever the factory OC is) settings.

Does this sound like a PSU problem? I had read that Seasonic had some similar issue with the FTW3 cards, but I actually think maybe I'm just at the bleeding edge of wattage requirement, in that sometimes it will spike higher than 850w? I think that because I saw a reddit post from someone who had a similar issue to mine with almost the same exact setup, only with a 11000k instead, and he said it was fixed when going to a 1000w, and even in the LTT video on the 3090 they stated sometimes they were seeing it draw higher than 850w.

Does the PSU seem to be the likely cause and if so, I'd like to ask what would be the best replacement? I originally was going to go with the Superflower 1200w as its up for preorder on Newegg right now ($320), and wasn't that much more (to me) than the 1000w, but then I saw that even though it was ranked as A tier on the tier liest, the Corsair HX1200 was ranked gold and of course are probably easier to work with warranty wise than a Taiwanese company. Unfortunately the HX1200 vanished as quick as I saw them up so right now I'm still sitting on the preorder, but have no problem changing over or waiting a bit for a different one if there's a much more compelling option. I really just don't know much about PSUs and just want to get this problem solved long term, which is also why I chose 1200w over 1000w; I originally chose the 850w for the 2080TI, and it was perfect for that, but the recent bump up by the 3090 has seemingly made it useless. I don't want the 1000w to similarly become obsolete if they decide to keep ramping up the wattage requirements.

Any help would be greatly appreciated.

jj9987 · April 30, 2021

It could also be PSU current protection. Some 3000 series cards (3080 and 3090) are said to pull such large amounts of current, that PSU current protection kicks in.

Either way, my guess is on the PSU as well. Choose something from this list, preferably Tier A.

May 16, 2021

On 4/29/2021 at 10:43 PM, McEgan said:

I'm running a 9900k / 3090 FTW3 Ultra / RM850x combo, and 99% of the time I have no apparent issues. Rarely though (sometimes the issue will not manifest even during 24 hour runs of Furmark or Ethereum mining, and sometimes it will take only an hour when playing a game with unlocked FPS), and only ever at absolute peak loads, will my PC suddenly shutdown and restart itself. Even rarer is sometimes it won't restart, but will simply give me a black screen and the GPU fan will kick up to 100% and will stay like that until I manually restart. This is with the 9900k at stock, and the FTW3 at its "stock" (whatever the factory OC is) settings.

If it were just the restart, I would say it could be the PSU. But the black screen and GPU fan at 100% tells me it's definitely not.