Question PC Reboots after installing Vega 64

[TechyGeek]

Hi All,

I have a 750W Seasonic PSU from 2014 and 4790k OC'd to 4.8. I installed VEGA 64 last month, and everything seemed smooth. I game 4k older titles, but 2-3 hours into a game PC reboots, with a message saying voltage is unstable.
What are my next steps? I thought that 750W PSU is more than capable of running a single vega 64.
Thanks!

 

[Despoiler]

What model is the Seasonic?

 

[n0x1ous]

make sure you use two separate 8 pin cables to the card and not 1 cable with two pigtails. Vega don't like that.

 

[TechyGeek]

I tried doing that. I ran 2 separate cables from PSU to video card. The machine rebooted within a minute of starting game. I put it back to single cable.
The Seasonic is Gold rated PSU (don't remember type). In the bios the 12v line read 12.16volts. Do I upgrade supply to 850W?

 

[Guru]

Change the PSU and see if there are issues, if no, then the PSU was the problem, if yes then you have a faulty GPU!

 

[DrMrLordX]

What kind of GPU temps are you seeing while gaming?

 

[DAPUNISHER]

Could be any number of things, obviously. But in your case it is more than just cliche to say that. If you have been running that overclock for years, it could be unstable now. PSUs also lose efficiency over time. Or you may simply need to use wattman to tweak your 64 for lower power usage and a better fan curve. Plenty of guides out there for doing it, and you can maintain or even increase performance in the process.

 

[Despoiler]

I tried doing that. I ran 2 separate cables from PSU to video card. The machine rebooted within a minute of starting game. I put it back to single cable.
The Seasonic is Gold rated PSU (don't remember type). In the bios the 12v line read 12.16volts. Do I upgrade supply to 850W?

If you split the cables that is why I asked about the model. Just to make sure you weren't overloading a rail. Usually it's not an issue on Seasonic supplies. 750w should be more than enough. If you think it's a case of pulling too much juice a $20 Kil-a-Watt wall power monitor is a great thing to add to your tool chest. It's cheaper than buying a new PSU. Like others have suggested it's hard to nail that down. 2-3 hours and then having issues seems more temperature related. The voltage error may be a red herring.

 

[alcoholbob]

Have you tried undervolting your Vega 64?

 

[coercitiv]

Have you tried undervolting your Vega 64?

I would rather introduce a lower power limit for the Vega and let it run at stock for starters. If system becomes stable, proceed to undervolt.

 

[Stuka87]

Just because a PSU is rated for 750W, doesn't mean its all on one rail. Although seasonics tend to be very good PSUs, its worth checking to make sure the two 8 pin connectors are on different rails.

 

[ZGR]

Does your motherboard give you a message upon reboot?

I would try undervolting the card and/or lowering power limit. This sounds PSU related.