VEGA 64 Boot Problem

[joey_the_dude]

Hello - I purchased a Vega 64 as an upgrade from my rx480 recently. The Vega snapped into the PCI slot no problem, all of the power connectors went in no problem, I should have more than enough power with the 750w. Problem is, once the card is installed and I try to boot the computer nothing happens. No life at all, no fan spinning, no noise, just nothingness. I put the rx480 back in and the comp boots up just fine. Is it safe to assume that the card is DOA and I should just get it replaced and try again? Is there something I am missing?

Core i5-7600 3.5 GHz Quad-Core Processor
ASRock - Fatal1ty H270 Performance ATX LGA1151
Ripjaws V Series 16 GB (2 x 8 GB) DDR4-2400 Memory
Sapphire - Radeon RX VEGA 64 8 GB NITRO+ Video Card
Corsair - Builder 750 W 80+ Bronze Certified ATX Power Supply

Thanks ahead of time.

 

[Zerileous]

Double check that both of the 8 (6+2) pin PCIe power cables are plugged in. Try re-seating them at the card and the PSU to make sure. Are you using two separate cables or one cable with daisy chained connectors? One of my buddies said he had a no post due to using a daisy chained PCIe 8 pin power connectors.

 

[Dolk]

It is advised that you have a 800+W PSU for Vega 64s. Addtionally like Zerileous said, you should use independent 12V PCIe power cables rather than one with a daisy chain. The amount of inrush current that these GPUs can create can max out a single PSU's 12V PCIe rail. These things are power hungry to the max.

 

[Zerileous]

Running Firestrike Ultra I saw a peak of 670W draw from the wall during Graphics Test 1. This is using the Liquid Cooling BIOS pushing 390W to the GPU at 1250mV.

I'm running a top tier 750W PSU. Maybe not ideal but I don't see myself actually overloading it. The OP has a more mid-range 750W unit, probably not a great idea to load it this heavily, however I don't think he'll have a problem running the normal BIOS with the power slider at 50% for a 300W power limit.

Edit: I saw a peak of 551W draw from the wall with the power slider set to 15% (on my LC BIOS) for 304W peak to the GPU @ 1200mV, with core clocks running in the low 1700MHz range. This is consistent with a strong overclock on the stock BIOS, and still leaves the PSU operating 200W below it's peak rating. Of course if the OP's PSU is an aging unit, it wouldn't be a bad idea to upgrade anyway. I just don't think it's causing a no-post.

 

[joey_the_dude]

It is advised that you have a 800+W PSU for Vega 64s. Addtionally like Zerileous said, you should use independent 12V PCIe power cables rather than one with a daisy chain. The amount of inrush current that these GPUs can create can max out a single PSU's 12V PCIe rail. These things are power hungry to the max.

I decided to replace the GPU and see if I still get a non post, if so I will try a better PSU, I was considering a 1000W platinum rated.

 

[Woomack]

My Vega56 /V64 BIOS runs fine with 550W Corsair 80+ Bronze and 600W SFX PSUs. Vega64 is not much different and the same RX480 can have 300W+ peak. V64 is 25W more but even if it would be 100W more then good 600W should handle it without issues. I just doubt it's PSU wattage. If it's the PSU then more like its quality or stability under load. It looks more like an issue with the card itself.
After OC or at manual settings, Vega64 can go past 300W but not at default settings.
Can always switch to low power BIOS and check if it boots. I think all Vega 56/64 cards have 2 BIOS chips.

 

[wingman99]

You should not have a problem with a 750 watt PSU for your complete PC including overclocking.

 

[RJARRRPCGP]

No fans? Sounds like a PSU trip due to a shorted FET on the Vega 64! I'm sorry, but it sounds like a faulty FET on the Vega 64 and thus the Vega 64 needs to be replaced.