Would an underpowered PSU in a system to cause GPU's to throttle?

[TonyTurbo78]

Question guys

Doing a bit of a watercooling project next week, currently running a OCZ 850w Gold PSU and have a pair of 390's in my system. I've one of those wattage meter plugs to measure my output, and the most I've seen it draw when heavy gaming and 100% usage is around 805w. In some games though, my GPU's seem to throttle way back out of the blue. Could this be the cause of having a PSU that I would assume is pretty close to the minimum you realistically need to run such high TDP cards.

Just trying to be a little pro-active here as I've 90% of a custom loop sat beside me awaiting a few extra bits next week before I start watercooling these 390's. Obviously soon to be running a pump now and a few extra fans for radiator cooling, will push a few more watts onto my system. Do you think now I have the chance, I should replace the PSU for something a bit meatier when I've got the PC stripped down for the loop to be built?

Thanks

 

[TonyTurbo78]

Ive not seen my 290xs throttle on my g2 850w, even at 1250mhz and 1.4v they kick along fine, have you increased the power limit to +50%?

Yes I have, always the first thing I do.

Saying that your drawing more power than me so im guessing your cards are drawing more amps than mine. Your not using vsync are you? If you say hit 144fps cause your not putting enough strain on the cards it will just start clocking down the cards as less power is needed, then when you get into a more detailed part of a game and your fps drop back down under 144fps you will see 100% use and max clocks again.

I have my fps locked in MSI AB to 120fps, but sometimes even if I'm playing Witcher 3 or GTA V and only hitting 70fps or 80fps, I still see the cards throttling down to 900mhz on the cores. Something isn't right and I can't figure out what it is. Was just wondering if it could be the PSU not getting enough juice to them. They just seem to throttle even when I've not hit my fps ceiling that I've locked in MSI AB (120fps)

 

[TonyTurbo78]

Ok, will get a 1200w superflower, should futureproof me this time.