PC Graphics

[Parisiani]

So I have just received a brand new radeon 6700 (NOT XT) and installed it in my PC, replacing a gtx 1070. It worked very well but, after shutting down my PC, when I try to turn it on, the PC won't start.

If I unplug the power cord of the GPU then plug it again, the PC finally starts and works very well... until I shut it down and try to turn it on.

My configuration: CPU: Ryzen 2700X, Mb: Gigabyte Aorus Ultra Gaming x470, PSU: Corsair RM550X 550W

This problem is very weird, notice that :

• once it starts, the PC works very well, I have been able to play video games, with a noticeable jump in FPS over my old GPU
• if I shut down my PC and start it again quickly, it works. The PC has to be shut down for a few minutes before it becomes unable to start.
• If I unplug the whole PC and plug it again, it won't start. I have to specifically unplug and plug again the GPU.
• I have updated the BIOS (last update from July 2022).
• It can't be a driver problem since the PC does not start at all.

[vialli100]

The minimum recommended PSU is 600w for RX 6700..

AMD Radeon™ RX 6700 | AMD

What make is your 6700?

[Parisiani]

Sapphire Radeon RX 6700 10GB.

I saw that PSU requirement but the card works fine once the PC is started. I also monitor the total power input on the PC power cord, it is not even 400W.

[Zeolit]

As AMD states, the following are recommended minimum requirements for installation of AMD Radeon™ RX 6700 XT graphics cards: • PC with at least one PCI-Express x16 graphics slot available on the motherboard. Minimum 650W system power supply • Minimum of 8 GB of system memory, 16GB is recommended.

It's clearly an issue from your PSU. and even though it looks to be working fine once it starts, you could encounter issues at every given moment due to the lack of power draw that the card might suck in certain situations. My best advice is NOT to run the computer with anything else than the 650w requested by AMD. I personally had a 650 Chieftec psu and recently changed it to a 850w rog strix along with purchasing the 6700. Always stay a bit over the limit in case of X-Y-Z type scenarios. 

[hrpuffnstuff]

Because electronics have something called cold boot inrush current and if that exceeds what your PS is capable of a no start will occur.  Many moons ago I ran Antec PS's and even though they had high wattage ratings they had low inrush capability which resulted in a no start.

They are the reason I learned about this issue and stopped buying weak PS's.  A fine example of this is with generators.  They have two ratings:  surge and constant wattage ratings so you know that when things are plugged in they can take that initial high draw then settle down to a steady output.  Computers do the very same thing.

[Parisiani]

Your story is interesting but, in my case, resetting the CMOS was enough. It has been a week and my PC starts and works perfectly. I have even upgraded my CPU (from 2700x to 5600x) and it still works very well.

I monitor the total power draw at the wall plug and it barely reaches 400W (PC monitor included...). My Corsair RM550X (550 watts) seems to be more than enough for my rx 6700.

[Parisiani · Accepted solution]

I reset the CMOS (I removed the battery for a few minutes) and it seems to work now: I can shut down my PC, wait some time and turn it on again (without replugging the GPU).

I don't see how the power requirements could explain my problem. My GPU has its own power requirement (220 W IIRC) but how can it assume how much the whole system need? Besides, I keep monitoring the power input for the whole PC (I have a power meter socket) and it never goes over 400 Watts. Also, the problem was at boot, it can't draw that much power just to start.