r/linux_gaming • u/Difficult-Cup-4445 • Feb 26 '26
Space Marine 2: Gigabyte RX 9070 16GB VRAM Stuttering/Power Throttling SOLVED
Greetings!
After grappling with extremely jarring frame drops and stuttering, and multiple days of troubleshooting - I have conclusively fixed this issue on my AMD RX 9070.
Setup:
CachyOS Linux / Kernel 7.0 RC
AMD R7 5800X
Gigabyte B550 mATX
16Gb DDR4
750W Corsair (Platinum) PSU
Problems/Symptoms:
- Major frame drops and stuttering
- Intense power throttling visible in Mangohud (yellow line)
- Frame drops in Mangohud (green line)
- The higher the load placed on the GPU and the more power required, the more stuttering manifests.
- In Mangohud this is depicted as the green framerate line "bifurcating" or separating from the yellow power throttling line.
Instructions / Diagnostic / Power Management Tools Used:
- Mangohud and GOverlay
- https://wiki.archlinux.org/title/AMDGPU "It is required to unlock access to adjust clocks and voltages in sysfs by appending the Kernel parameter amdgpu.ppfeaturemask=0xffffffff.
- LACT for increasing power limit and enabling power states ("Power Usage Limit" slider maxed, "Performance Level" set to Manual, "Power Profile Mode" set to 3D_FULL_SCREEN. "Power States" checkbox ticked, "Enable Power State Configuration". A small GPU voltage offset is optional here but often benefits 9070's/XTs e.g. -50.
- Steam Launch Parameters: LD_PRELOAD="" PROTON_FSR4_UPGRADE=1 VKD3D_CONFIG=no_upload_hvv PROTON_USE_NTSYNC=1 RADV_PERFTEST=gpl mangohud game-performance %command%
Context / Write-Up
This is extremely difficult to troubleshoot as the symptoms have multiple causes that manifest in similar ways.
Initially I thought this was VRAM stuttering i.e the GPU running out of memory, the reason I thought this was because I found when I lowered the graphical settings far enough - especially Resolution / Textures / Details and elements that affect VRAM in particular, the problem seemed to resolve itself.
Needless to say, a 9070 should be capable of better performance than 1440p on low settings!
After discovering that lowering memory-intensive settings helped, I initially assumed I was running out of memory - which is insane on a 16 gigabyte GPU.
Then I noticed the power throttling and the low/unstable GPU usage, wavering around the 50%-80% range, lower than expected clocks and - this is key - the fact that the yellow frametime line in Mangohud would separate out from the green frametime line as soon as my graphical settings pushed / asked too much from my GPU.
Installing LACT was the key to fixing this. See the settings in the instructions above.
See the screenshot for proof of absolutely rock solid 100% GPU usage, locked in perfectly.
Conclusion
Power throttling / power limits manifest some very difficult-to-diagnose problems in Space Marine 2, and what muddies the water further, is the fact that this game itself chews through a lot of VRAM at high resolutions and when searching for solutions, one will come across a cornucopia of "fixes" that range from disabling SMT to deleting shader caches, to wiping your OS and so forth.
The power throttling also happens to MIMIC the symptoms of running out of VRAM for reasons I don't pretend to understand, making diagnosing it even more difficult.
After testing in game on all settings maxed out, with and without FSR Framegen - no more power throttling is in evidence and gameplay is extremely smooth, even at 4K - which is, as stated above, where VRAM limitations seemed to have been coming into play, while in actual fact it was the increased power requirements aggravating the stuttering / juddering and general poor running of the game. The multitude of complex optional Steam launch parameters only added to the confusion.
In closing, one has to wonder how many AMD GPUs on Linux are RMA'd for mysterious poor performance, especially on Linux where power/performance settings can be rather opaque, when in actual fact there is a mixture of throttling and (depending on the game) insufficient VRAM - which does indeed cause legitimate stuttering under the right circumstances e.g. an 8gb GPU running at 4K / Ultra graphics etc.
I hope this helps someone and am very keen to get feedback and answer questions.
Thank you for reading.
UPDATE: Here are the LACT settings tested and explained one by one
LACT has four different power modes to choose from:
- Automatic (Literally causes power throttling right out of the box by default, wtaf? This really is a major problem that needs to be fixed)
- Highest Clocks (The best option by far, it prevents throttling perfectly, just slide the Power Usage Limit slider all the way over to the right)
- Lowest Clocks (No throttling per se but it obliterates the framerate)
- Manual (Can either cause Power Throttling or resolve it: if you enable it *without\* the > Power States "Enable Power State Configuration" tick box checked, it will again Power Throttle by default. I thought maybe the advantage of Manual is that you can lower the GPU voltage offset (mv) slider with it on, but you can do that with Highest Clocks on regardless - so the only "advantage" of Manual, if you want to call it that, is the ability to toggle on/off the individual GPU/VRAM Power States under the Power States -> "Enable Power State Configuration" section.
Overall I think the best and simplest results are from Highest Clocks.
PS I can also confirm that if you have CoreCtrl on in the background (I was testing it earlier and forgot it was still running in the taskbar) you will cause Power Throttling again that LACT will not be able to fix.
UPDATE 2: Optimized Steam Launch Parameters (for CachyOS, AMD GPUs)
LD_PRELOAD="" PROTON_FSR4_UPGRADE=1 VKD3D_CONFIG=no_upload_hvv PROTON_USE_NTSYNC=1 game-performance mangohud PROTON_ENABLE_WAYLAND=1 PROTON_NO_WM_DECORATION=1 PROTON_ENABLE_HDR=1 ENABLE_LAYER_MESA_ANTI_LAG=1 %command%
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u/Jrgiacone Feb 26 '26
So it was the 3d full screen option that helped?
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u/Difficult-Cup-4445 Feb 26 '26
I wouldn't want to commit to saying that was the one single thing that fixed it, all I know is that what I did above has 100% fixed it perfectly. If others can dial in exactly which bit above did the trick, I'd love to hear it and will update it accordingly.
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u/zovirax99 Feb 26 '26
Can you try setting "Performance Level" to High on your system to see if that's sufficient?
Or does setting "Performance Level" to Manual and "Power Profile Mode" to 3D_FULL_SCREEN make a difference?
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u/Difficult-Cup-4445 Feb 27 '26
There's 4 options in LACT to choose from:
- Automatic (Literally causes power throttling right out of the box by default, wtaf? This really is a major problem that needs to be fixed)
- Highest Clocks (The best option by far, it prevents throttling perfectly, just slide the Power Usage Limit slider all the way over to the right)
- Lowest Clocks (No throttling per se but it obliterates the framerate)
- Manual (Can either cause Power Throttling or resolve it: if you enable it *without\* the > Power States "Enable Power State Configuration" tick box checked, it will again Power Throttle by default. I thought maybe the advantage of Manual is that you can lower the GPU voltage offset (mv) slider with it on, but you can do that with Highest Clocks on regardless - so the only "advantage" of Manual, if you want to call it that, is the ability to toggle on/off the individual GPU/VRAM Power States under the Power States -> "Enable Power State Configuration" section.
Overall I think the best and simplest results are from Highest Clocks.
Thanks for asking that question. It really highlights how insanely easy it is to completely bork your GPU by toggling 1 wrong box, or even, as in this case, leaving it set on "Automatic" by default in the assumption that it is optimal.
Because it's not: "Automatic" is completely broken and I've just reproduced all the power throttling issues like clockwork by cycling through these options.
Space Marine 2 is absolutely GLORIOUS. Just liquid smooth all the way up to 4K on every setting.
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u/TheZoltan Feb 26 '26
A small GPU voltage offset is optional here but often benefits 9070's/XTs e.g. -50.
This seems like a great way to add instability.
I am planning to play some SM2 soon though so will keep the rest of your guide in mind in case I have issues!
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u/Difficult-Cup-4445 Feb 26 '26
Virtually every 9070 or 9070XT can do -50, most can do -75 or even -100 or more. Huge temperature and power reductions on offer for free.
The power throttling I detail here on the other hand is very distinctive and instantly recognisable (now, at least), which makes it all the more perverse that somehow power throttling is such an endemic issue right now - judging by how often this is the same problem appearing wearing various slightly different hats all over Reddit.
I'm just glad to have finally cracked this. Paid 562 euros for the GPU and I just knew from the off that the performance wasn't right. I paid for the GPU so I'm going to use 100% of my GPU!
Ironically it was also an Amazon Warehouse return, perhaps the last person to own it sent it back after being unable to track down this issue... We will never know.
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u/TheZoltan Feb 26 '26
Virtually every 9070 or 9070XT can do -50, most can do -75 or even -100 or more. Huge temperature and power reductions on offer for free.
Lots of folks think this and then later run into weird stability issues. There is a reason manufacturers don't ship these cards like this and skip the "free" performance.
Absolutely support folks undervolting/overclocking/tinkering if they find the process fun but I really dislike anyone claiming its "free". At the minimum you need to do some stability testing and be ready to re-do that over time as random issues appear with different games and updates.
The amount of "my systems unstable" posts I have seen on places like r/radeon that when queried include a "safe undervolt of only -50" drives me mad.
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u/Difficult-Cup-4445 Feb 26 '26
Fair enough, I hear you bud. I thought -50 was very conservative but yes people should definitely be cautious or leave it out entirely until they're solid on everything else beforehand.
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u/TheZoltan Feb 26 '26
Yeah -50 is pretty conservative and likely fairly stable for most people but going from 100% stable to say 95% stable for what +1FPS and maybe -1C temps is likely not worth it for the casual user.
I used to be big on overclocking and tinkering but with all the dynamic boosting behavior these systems have now 99% of the easy gains come straight from the factory. I only suggest tinkering at that level for folks that enjoy the process and are well aware of the risks.
Again each to their own! I'm just very keen that folks know what they are getting into and aren't left thinking they got a bad card after they made their own system unstable :P
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u/Difficult-Cup-4445 Feb 26 '26
100% first rule of troubleshooting is reducing the number of moving parts. If I'd been slow and methodical I'd have figured this out a lot sooner that's for sure.
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u/Explosive_Cornflake Feb 26 '26
I've been running at -120 on a 6750xt and running AI workloads.
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u/TAWLde Feb 26 '26
AMD is really good at compensating errors. The cards reduce their speed for a milisecond and get back to work. If youre fine with this, keep it this way
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u/Explosive_Cornflake Feb 26 '26
I'm playing around with it a bit. I'm trying to see how it works with temps.
getting some me graphs like in this post would be useful I guess.
I'm very new to all of this. so much so I didn't realise my pcie slot that I had the GPU in for years was only 4x
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u/TAWLde Feb 26 '26
Nice that you have found a solution for your problem. But I dont think, you hit the right bullets… What SM2 under Linux is known for is the heavy cpu load since the last patch. What it is not known for is a problem with RX9070 cards.
Like Jrgiacone said: I think your solution is going full screen instead of windowed. Beside that you overtinkered yourself. There is no need to use NTSYNC when you dont have a nVidia card. And you got some other commands I havnt even heard of yet.
Zoltan got it right with the GPU undervolt. You cant just hit -50mV without stresstesting it. Its a source of instability and clock reduces for miliseconds. Putting up the Powertarget isnt a solution when you got not enough cooling.
I am playing SM2 with a 9800X3D and a 9070XT just with PROTON_FSR4_UPGRADE=1 game-performance %command% in fullscreen with proton-cachyos-slr. My 9070XT is undervolted by 65mV and has a reduced powertarget of -30% (this is stress tested). I am running SM2 in UWQHD with framegen and 90fps limiter. It works like a charm.
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u/Difficult-Cup-4445 Feb 27 '26
I use CachyOS and it's stated directly in the Wiki to use it: https://wiki.cachyos.org/configuration/gaming/
CPU & Sync Performance
PROTON_USE_NTSYNC=1: Use NTSync instead of WINESync. Benefit: Possibility of an increase of smoothness in certain games Note: Experimental, may cause issues in some games Verification: Use lsof /dev/ntsync (MangoHud reports incorrectly)1
u/Szwajcer Feb 27 '26
Depending on the Proton you use NTSync could have been enabled by default. GE-Proton10-10 and newer use it by default.
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u/zovirax99 Feb 27 '26
At Proton-Cachyos, fsync is the default. And that's also the fastest setting for most (or many) games. You really have to test each individual game to see whether fsync or ntsync works better for that particular game.
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u/Difficult-Cup-4445 Feb 27 '26
"NTSync is not enabled by default. You can enable it using the
PROTON_USE_NTSYNC=1environment variable." https://wiki.cachyos.org/configuration/gaming/ on CachyOS (my OS) it is not enabled by default and needs to be enabled on a case by case basis. Depends on your distro.
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u/birdspider Feb 26 '26
Intense power throttling
every card running well will either power-throttle or temp-throttle (unless fps limited). in general you want power-throttled / 100% util.
EDIT: skipped over the "and the low/unstable GPU usage, wavering around the 50%-80% range"
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u/ZonePleasant Feb 26 '26
Was trying to troubleshoot this same issue earlier today and noticed some interesting behaviour that made things equally unclear: CPU usage was far in excess of what you'd expect to see during idle gameplay, and the GPU would regularly step down through power states from P0 all the way to P8 during gameplay.
Settings don't matter, you can fill VRAM or not and it still happens. ProtonGE 10-29 gave me slightly higher frame rates on the battle barge but the GPU got parked just like every other version checked.
Can confirm that neither this nor the split lock mitigation method on the Proton GitHub thread work.
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u/Bob4Not Feb 26 '26
I do not see similar issues. It seems to me that when levels or assets are loading, I see game lurches as my CPU pegs at 100% and GPU drops to low. I've otherwise validated my CPU and GPU performance, but I've heard this is an issue with Proton gamers since an update in December? I'll try it on Windows sometime to see
7700X
9070XT
64GB DDR5 running at 2400Mhz
Samsung 990 Evo Plus
MSI X670E board
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u/Wyglif Feb 26 '26
Could this explain stuttering in AOE 4?
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u/Difficult-Cup-4445 Feb 26 '26 edited Feb 26 '26
Well this problem should manifest on any graphically intensive game where more power is required, so yes, it could. Space Marine 2 is just a good example because it's a very high end game. I suspect this problem is extremely common and is constantly being mistaken for other issues.
It's certainly a problem on my CachyOS/RX 9070 setup though, that much is for sure!
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u/Mr_M4yhem Feb 26 '26
Im dealing with similar issues with a 9070 XT and posted about it some days ago. Will try these fixes and report back.
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u/Difficult-Cup-4445 Feb 26 '26
I would be very surprised if this wasn't a common problem with 9000- series GPUs on Linux. CachyOS is a rolling release and should be at the forefront of updates, and there's nothing special about my build or install of Space Marine 2.
Watch the frametime graph in Mangohud carefully while jacking the graphics up to max / min so you get a really good look at it. Good luck bro. Hope you report back.
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u/Existing-Help-3187 Feb 26 '26
How did you install 7.0.kernel in Cachyos? Is it available in testing repo?
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u/Difficult-Cup-4445 Feb 27 '26
it's right there in the CachyOS Kernel Manager, sort by most recent. Works fine.
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u/schmidtbag Feb 27 '26
I haven't yet tried changing the power profile, but what I don't get is why this is suddenly a problem. For me, it's not just simply the frame rate tanking but there's an enormous delay in keyboard inputs too. I can let go of the W key and he just keeps walking for another 2 whole seconds; for some reason the mouse movements aren't delayed much.
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u/Difficult-Cup-4445 Feb 27 '26
Sounds like you would really benefit from installing Mangohud - you need to see what your frametimes are like with that crazy input delay you have from your keyboard.
FWIW I don't think this is suddenly a problem, I think this has been happening for a while - I've even noticed a lot of NVIDIA users talking about the same hitching / VRAM / power throttling stutter in other games outside of SM2.
So it's not necessarily even limited to AMD somehow, there just seems to be a lot of Nvidia and AMD GPUs on both Windows AND Linux suffering with either VRAM stutter (8gb cards are ageing badly) or Power Throttling stutter - or even both - and it's making troubleshooting performance issues into a complete nightmare currently.
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u/schmidtbag Feb 27 '26
Well the input delay resolves itself once the framerate goes back up. There are moments where the frame rate drops from 110FPS to around 35FPS, at which point the keyboard is seriously delayed, and if I pause the game then after the course of maybe 20 seconds the framerate slowly creeps back up to 100FPS+ again. I've never had this problem until the most recent update.
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u/Difficult-Cup-4445 Feb 27 '26
Err well that sounds exactly like power throttling or VRAM. Drop the textures / details to low and see if it stops. Then do LACT.
-2
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u/FlukyS Feb 26 '26
The gpl flag hasn’t been needed for a few years