Graphics Cards

[Cibot]

GPU: Radeon 6900 XT (reference)

CPU: Intel Core i7 9700 K

Motherboard: MSI Z370 Tomahawk

BIOS Version: 1.B3 (latest) (7B47v1B3(Beta version))

RAM: 4x8GB G.Skill DIMM DDR4-3200

PSU: Corsair TX-M Series Modular TX750M 80 PLUS Gold

Case: be quiet! DARK BASE PRO 900 rev.2,

Operating System & Version: WINDOWS 11 Pro Version 22H2

GPU Drivers: AMD 22.11.2

Chipset Drivers: Intel Chipset Driver - 10.1.18508.8239

Background Applications: DISCORD, CHROME, Steam, Plex, Blitz, Wallpaper Engine ... more

Monitor: 3x1440p 165 Hz

Yesterday I upgraded my GPU from a 1080TI to a 6900 XT and expected about 80-100 % FPS increase. 
To my surprise, the fps actually went down by 50-70%. What could I be doing wrong? I've tried DDU with both nvidia and amd drivers. Doing it again in save mode. Then also trying it out with older AMD drivers. After that didn't work out, I completely reinstalled windows, did not help at all. 
When I try to run furmark, it actually seems like the GPU has decent performance. It gets around 210 fps at 1440P preset while my old GPU gets around 110 fps. 

Path of Exile Before: 150 fps average
Path of Exile After: 25 fps average

Cyberpunk Before: 55 fps average
Cyberpunk After: 10 fps average

Escape from Tarkov Before: 100 fps average
Escape from Tarkov After: 30 fps average

[Cibot]

Just to be safe on whether the GPU is good or not, I tried it out in a similar PC and it worked absolutely fine. FPS increased by about 90-150 % which was what I expected. Then I plugged it back into my pc and suddenly games are running better. Not at the expected performance but still like 20-30 % faster than my 1080 TI. I suspect it might be something going on with my power cables since I have a single 8-Pin to Dual 8-Pin cable. That worked flawlessly with the 1080Ti but maybe since power draw is higher with the 6900 XT, it's somehow failing. As such I've ordered a new cable and will be updating once I have tried it out on wednesday.

[cpurpe91]

Yes, these cards require more power, and you will need 2 individual cables to supply it. Did you order the exact cable you need? It is unsafe to use cables that are not manufactured specifically for your PSU as the pinout may be different and DAMAGE your hardware. It is a very serious thing that can and has happened because people thought cables were interchangeable between different PSUs. It is best to use the cables that came with the unit or order the new cable directly from the manufacturer. On the product page it says you receive two individual cables with the PSU do you not have both? 

[cpurpe91]

[Cibot]

Aight I'll try it out. I was just expecting that when the card did not get enough power, the PC would shut down. But even if I run furmark, which should theoretically use up 100 % of the GPU, it doesn't shut down and peaks at about 250 Watts I think. I ordered from the original Corsair store since I do know that incompatible cables can fry hardware. I know that they have enough cables usually but I totally lost the cables when I moved to another appartment. So no clue where they are now  

[Moist]

Just out of curiosity have you checked in your BIOS to make sure your PCIE is running in 4.0 and not 3.0? Usually that wouldn't make that large a difference but might be worth checking.

[Cibot]

As far as I can tell, my motherboard only supports up to PCIe Gen 3. So I can not go up to PCIe Gen 4. Same is with the other PC i have here and that one also doesn't support Gen 4 but still got better performance. Don't think that's an issue here. 

[cpurpe91]

PCIe gen 4 is not supported on the 9th gen Intel platform. 

[hrpuffnstuff]

I too went from a 1080 to 6900xt and my fps doubled in games and I was running a x570 w/3900x.  When I upgraded to a 5950x they went up again.

Today I'm on a z790 w/13900k and its running its best yet on 22.11.2 so I would check for corrupt system files and incorrect settings.  Also try uninstalling the drivers using the AMD standalone uninstaller in safe mode, it will force you there, then reinstall them as they sometimes get corrupted.  If you see any missing icons they are an indication that you need to do this.

[cpurpe91]

Are you running two PCIe cables from the PSU to the GPU? Not two connectors on one cable but two individual cables?

[Cibot · Accepted solution]

I guess initially my GPU was not fully seated or something. Performance is now pretty fine, roughly 50-70 % faster than before. Even without the additional cable. I guess the single 8-Pin to Dual 8-Pin cable is good enough. To be safe, I have plugged in an additional 8-Pin cable, so I now have 2 8-Pin cables connected to the GPU, but that did not impact performance. 

[cpurpe91]

The reason I stressed it so much to use multiple cables is because one single 8 pin is only designed to supply 150 watts, while the PCIe slot provides up to 75 watts. The max power draw of a 6900XT is well over the 225 watts that a single 8 pin and the PCIe slot provide at 300 watts.