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The Radeon RX 6900/6950 XT Owners Thread.

Soldato
Joined
21 Jun 2006
Posts
3,424
Location
UK
Put a waterblock on my 6900 XT today.

Now for some reason the card won't go over the 300w limit.

Red Devil Limited Edition.

Card is around 38°
 
Soldato
Joined
28 Aug 2017
Posts
2,755
Location
United Kingdom
Put a waterblock on my 6900 XT today.

Now for some reason the card won't go over the 300w limit.

Red Devil Limited Edition.

Card is around 38°

tried re installing the driver?, could be a bug, to note my aircooled asus 6900xt runs 37/38 degrees edge temp at idle with a 1600rpm profile 45 degrees hot spot.

and lastly your using the mpt?, go back a few pages and @LtMatt has a handy guide :) (post 453)
 
Associate
Joined
27 Sep 2020
Posts
34
The magical question. The only safe option is the default option.

That said, I personally use 300W Power Limit GPU (W) seen in the screenshot below for my 24/7 MPT settings. I leave power limit at 0% in Radeon Software as i like a 300W ceiling for board power. This is plenty for games IMO and you can run silent fan profiles and keep the Junction temperature below 110C - throttling temp - assuming you have good case airflow, plenty of intake (2-3 fans) and 1+1 exhaust top and rear fan.

I undervolt the MAX SOC voltage to 1.017v (1.000v ish actual under load) which saves a few watts of power and heat.

MPT

1. Download MPT and GPU-Z.
2. Run GPU-Z and save the BIOS somewhere safe on your PC.
3. Launch MPT, click Load, load the BIOS you just saved.
4. Select the drop down box and your 6900 XT.
5. Click Power and Voltage tab.
6. Change only the following, Max soc voltage, Power Limit W, and or TDC (don't really need to touch TDC unless going for silly high power draw).
7. Once you've made your desired changes, click Write SPPT.
8. Reboot.
9. Your settings are applied on next boot.
10 Click Delete SPPT in MPT to restore default values.

HBwF3VL.png

On the 6900 XT you'll get best results by lowering voltage from 1.175v, but this can be done in Radeon Software > GPU Tuning.

This is a very helpful post, especially for PC noobs like me who decide to buy high-end components. Thank you very much for taking the time to post this. I've just gone ahead and unlocked the power limit on my 6900 XT and it's nice to finally see it go past 293W. Unfortunately, my room has become noticeably hotter a mere 30 minutes after raising the GPU power limit. I'm now hitting 345W and 2580Mhz in borderlands 3, which seems okay for a reference card, and I got an 8fps performance boost which seems alright.

I'm wondering, what's the highest power limit you'd be comfortable to go for with your 6900 XT? I have no idea if something like, say, 375W is safe for the reference 6900 XT but I think you mentioned that figure somewhere in this thread. Heck, I don't even know if I'm safe to carry on running the card on 345W, but I'm going to continue with that just to see if this has any impact on the persistent crashes I'm getting.

I'm confused about the effect of VRAM clock speed on gaming performance. Using the borderlands 3 built-in benchmark, I'm seeing a very tiny performance boost with VRAM clock speed set to max, but you recommended to set the clock to a lower figure.

Anyway, thanks again for the helpful information you provided.

(Just to clarify - I'm using 300W on MPT, which becomes 345W with the Adrenalin software power slider at max.)
 
Associate
Joined
27 Sep 2020
Posts
34
So I think I may have got a really good chip.
So with a power target of 300w and a voltage of 1150mv with nothing else touched.
Get clock speeds around 2475mhz.
Around 20300 timespy gpu.
With a small frequency bump to 2650 and mem clock.
https://www.3dmark.com/spy/17818379
The waterblock alone as gained me around 5 fps in shadow of the tomb raider at 1440p
148-153.
What does everyones stock clock boost to in games standard?

That sounds like a very good result. I haven't done any formal or standardised testing, but here's a quick summary of my 6900 XT clock speeds during a specific action sequence within borderlands 3:

- 2340Mhz at 293W and everything on stock settings
- 2460Mhz at 345W, once again with absolutely everything else at stock settings
- 2510Mhz at 345W with my best attempt at an overclock and undervolt.

I should add that these figures are estimates and are confined to a specific portion within each game. My clock speeds go up as high as 2580Mhz in Borderlands 3 but I haven't seen them exceed that value.

I've also taken a very quick look at performance within Resident Evil 2 and the clock speed struggles to even reach 2500Mhz (at 345W and overclocked) during a very quiet part of the game, at the beginning. With the stock bios at factory default settings, the card does 2330-2370Mhz.

In Hitman 2018, in the Mumbai level, I'm getting clock speeds around 2340Mhz (default values and stock bios) and 2500Mhz with the card overclocked and MPT'd to 345W.

I feel like I must be doing something wrong.
 
Caporegime
Joined
12 Jul 2007
Posts
40,410
Location
United Kingdom
Put a waterblock on my 6900 XT today.

Now for some reason the card won't go over the 300w limit.

Red Devil Limited Edition.

Card is around 38°
Have you validated that your MPT settings are applied? If you change driver, reinstall OS, etc, these settings are lost.

Might be worth re-doing them following the steps i list above?
This is a very helpful post, especially for PC noobs like me who decide to buy high-end components. Thank you very much for taking the time to post this. I've just gone ahead and unlocked the power limit on my 6900 XT and it's nice to finally see it go past 293W. Unfortunately, my room has become noticeably hotter a mere 30 minutes after raising the GPU power limit. I'm now hitting 345W and 2580Mhz in borderlands 3, which seems okay for a reference card, and I got an 8fps performance boost which seems alright.

I'm wondering, what's the highest power limit you'd be comfortable to go for with your 6900 XT? I have no idea if something like, say, 375W is safe for the reference 6900 XT but I think you mentioned that figure somewhere in this thread. Heck, I don't even know if I'm safe to carry on running the card on 345W, but I'm going to continue with that just to see if this has any impact on the persistent crashes I'm getting.

I'm confused about the effect of VRAM clock speed on gaming performance. Using the borderlands 3 built-in benchmark, I'm seeing a very tiny performance boost with VRAM clock speed set to max, but you recommended to set the clock to a lower figure.

Anyway, thanks again for the helpful information you provided.

(Just to clarify - I'm using 300W on MPT, which becomes 345W with the Adrenalin software power slider at max.)

You are most welcome. :)

For 24/7 use, i like a limit of 300W. I'm on the reference cooler and if you go over 300W you can't have the fans running at a silent speed anymore.

See my post above for advice on what is 'safe'.

Test several games. I found that at some point after 2012Mhz i lost FPS in games, but gained points in synthetics. This played out with a 6800 XT and a 6900 XT.

YMMV, so have to test several games and see what's what. If it works okay for you run it at 2150Mhz with Fast Timings on.

Regarding your post above about clock speeds, it's perfectly normal. Some syenthics such as Timespy, Firestrike etc will occupy all the shader and compute cores fully, so in these scenarios you'll see a lower GPU clock as the power draw is higher.

Some games can be like this too and be more demanding so you get a lower core clock. Some games will be light on the GPU like Call of Duty Warzone and in this you might see lower power draw and higher clock speeds etc. You get the idea.
 
Last edited:
Associate
Joined
11 Jan 2021
Posts
9
That sounds like a very good result. I haven't done any formal or standardised testing, but here's a quick summary of my 6900 XT clock speeds during a specific action sequence within borderlands 3:

- 2340Mhz at 293W and everything on stock settings
- 2460Mhz at 345W, once again with absolutely everything else at stock settings
- 2510Mhz at 345W with my best attempt at an overclock and undervolt.

I should add that these figures are estimates and are confined to a specific portion within each game. My clock speeds go up as high as 2580Mhz in Borderlands 3 but I haven't seen them exceed that value.

I've also taken a very quick look at performance within Resident Evil 2 and the clock speed struggles to even reach 2500Mhz (at 345W and overclocked) during a very quiet part of the game, at the beginning. With the stock bios at factory default settings, the card does 2330-2370Mhz.

In Hitman 2018, in the Mumbai level, I'm getting clock speeds around 2340Mhz (default values and stock bios) and 2500Mhz with the card overclocked and MPT'd to 345W.

I feel like I must be doing something wrong.

It seems to be within 100mhz of mine before I got the waterblock on.
Mine was held back by the junction temps slowly decreasing clock speed.
On complete stock with 255w and nothing altered clock speeds started around 2440 and dropped as the tjunction hit around 72c to 2300ish.
I have noticed that some games push the gpu a lot more than others.
Cold war for example only runs at 2320-2550 but this is pushing 220fps.
Shadow of the tomb raider usually boost at a consistent 2549.
All stock with mpt tdp 300w.
Going to get some runs with all stock 255w hope this helps :)
 
Associate
Joined
20 Nov 2020
Posts
1,120
The worst thing about the 6900xt is the lack of support from AMD for the 3x8 pins cards. These cards are able to use much higher power limit but they are limited to 375W by the driver. And maybe you can trick the driver with MPT to raise the power limit but there should be driver support from AMD or the cards manufacturers.
 
Soldato
Joined
6 Aug 2008
Posts
4,131
Location
Birmingham
CA19-AE24-BC75-4-D01-938-A-F51-EC38840-AF.jpg
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[/IMG] Just love this card...

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cNxjmmb
 
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Soldato
Joined
30 Mar 2016
Posts
2,884
Location
East Lothian
I have a question regarding CSM and SAM. I know @LtMatt has spoken about this before...

So when I built my new rig a couple of weeks back, I included a pcie adapter card with additional sata ports for my SSDs as I had used all those provided by the motherboard. With CSM disabled by default, I would stick on the motherboard splash screen and have the white LED warning light on my motherboard show. I had a work around to get past the splash screen so it wasn't a huge problem, just annoying. Shortly afterwards I enabled SAM in the bios. Later, I went back into the bios again and enabled CSM. This fixed my splash screen issue and stopped the white led warning showing on the motherboard - happy days. Looking at the bios again it still shows that SAM is enabled so my question is, is it only necessary to have CSM disabled to enable SAM and then ok to go back and enable CSM afterwards as I have done? Or, is my bios only showing SAM as enabled but it's not actually functioning as CSM is now enabled? Can SAM and CSM function together?
 
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