RX 7900 XT test in DCS 4K & VR [cancelled due to stutters / latency spikes]

So, my Fractal Design Meshify C officially only supports video cards with a length up to 315 mm.
But that assumes a 25 mm fan is mounted in the front.

So we have 340 mm to work with from the backside to the fan cage.

The reference RX 7900 XT and some custom boards such as the ASRock Phantom and the Sapphire Pulse fit this space.

But I have read multiple accounts of those cards getting incredibly hot in some spots only, indicating bad contact/cooling.

The coolers that performed a lot better, at least on the very similar RX 7900 XTX chip (same die), were the ASUS TUF, Sapphire Nitro and ASRock Taichi.

I looked at the dimensions for all of them (they are all over 340 mm) and figured that the Taichi might just fit, because it only stretches the full 346 mm in the center and not across the full width, unlike the others.

It was not easy though, to get the L-shaped rear into the rear slot but with rotations across all three axes and my girlfriend helping stretch the case open a bit for that extra mm, we managed.

Look at this:

You can see here how the center front of the card (black) stretches beyond the fan cage without touching it. It uses the space between the fan cage and the dust filter very efficiently.

Like the pilot in the A-4, this video card is not sitting in the case: it wears it.

Full review will follow


OK so despite gathering about 20 different framerate numbers in VR and 4K scenarios with the RTX 3080 last night, I’m not showing any sheets with performance comparison now. There have been some showstoppers that made it pointless to run every scenario on the RX 7900 XT and compare the numbers. The expectation is between 20 and 30% GPU performance improvement, based on most games and benchmarks.

  1. In VR, the headset does not seem to render at a solid 60 Hz, unlike what I’m used to in OpenXR with other GPUs (RX 6800 XT and RTX 3080). It feels choppy when looking around, like we used to have in SteamVR with the 45 or 90 fps rendering.
  2. In the DCS framerate monitor, the RTX 3080 displays GPU bottlenecked at X fps most of the time, but the RX 7900 XT only shows CPU bottlenecked (rendering thread).

Speculating, these issues seem to indicate problems with the way the driver interfaces with OpenXR runtime.

Latest AMD Adrenalin Edition 23.7.2
Latest Windows 10
Latest Open Beta (using the multi-threading binary)
WMR OpenXR Runtime (Microsoft Store)
WMR Portal
HP Reverb G2

Ryzen 7 5800X3D
32GB (4x8GB) 3600 MHz CL18 (4000 MHz kit, clocked down)
B550 Aorus Pro MoBo
RM850x PSU

And yes, I did run DDU when switching GPUs and cleaned out all the DCS shader caches with this script, even edited it to clean some more folders in the Mods/Terrain subfolders and ran a repair afterwards.

I guess the one thing I could still try is to use a different OpenXR runtime, i.e. OpenXR Toolkit.

If that doesn’t work, I’ll have to send it back. I’d rather game in a fluid 45/60 fps than have a more powerful card at 90 that drops back to 45 fps when it can’t make that. I am not prepared to lower my DCS graphics settings enough to keep 90 all the time, I like shadows in my cockpit, especially if I’m paying ~250 eur. It would be a shame as I was looking forward to playing with lots of Linux distributions, which is a lot easier with an AMD card.

P.S. I had trouble with accidentally changing the DCS settings and I accidentally tried to run the shader cache cleaner script in non-admin mode, and then faced a PowerShell security setting (execution policy) preventing me from properly running it (could only spot that when running it from the terminal) so I have been spending all afternoon on this, with many pc restarts too.

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I’m on almost the same setup as you are, except I have a 5800x3d, and I eventually gave up and went back to TrackIR. I love the IDEA behind VR, but I think until some company like AMD sits down and tries to integrate an entire GPU/CPU/RAM/Drivers/even buy a VR corp itself, to get a dedicated system together that can offer a more flawless experience. I DO think it can be done with current technology, but my system would change from one bootup to another. Sometimes it was flawless and free of stutters, other times, it’d be completely unusable.


Oh hey! Nice to see you back!

sounds like a driver/setting problem.
23.7.1 was the VR Fix Drivers.

I will look around and see what I can dig up for custom settings.

But if DCS is saying CPU bound, then it’s not GPU related.

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Welcome back!

I do too. Did you mean 7800X3D?

FWIW, DCS+OpenXR worked pretty well with the 5800X3D CPU both on Nvidia RTX 3000 series and AMD RX 6000 series. I think it’s just a problem with the RX 7000 drivers.

It would be nice to get it to work, but luckily I can still send it back within 30 days, keep €250 and stick with the 3080. I haven’t actually sold it yet.

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I still love you all - I’ve been lurking and flying solo and with the Hollo Pointe crew, but I’ve improved my skills to the point that I don’t get shot down EVERY time I fly!

Yeah - sorry - I saw 7800x3d in another thread and got confused.

I even bought 64g of RAM to try and improve things with no luck.

I do think AMD could solve this. I just think they’re becoming too focused on stock instead of the 3-5 year plan.

OH and just FTR - gang - Sryan (I won’t @ him but he knows) is growing up good! Almost has his PhD and is in the company of a BEAUTIFUL young lady. I had to re-hinge my jaw when he sent pics. I feel like a cousin or BB to that young man’s growth and development.

MudSpikers Forever!!


They are focused on Fixing rDNA3, and Working on Making sure the problem doesn’t continue to rDNA5, rDNA4 Large GPUs were cancelled.

The latency is likely the result of the delay in the cache to infinity fabric, the infinity fabric needs to be able to transfer a lot faster, they underestimated the lag between the GCDs and MCDs effect.

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Unfortunately, it seems @SkateZilla is right and this latency is probably a hardware issue. The VR driver update of July certainly hasn’t made the DCS VR experience on the RX 7900 XT better than it is on the last gen cards (RTX 3080, RX 6900 XT).

Seeing as there will be no RX 8900 XT, I guess I will join our AMD expert in waiting for the RX 9900 RXxXTXxXR (just guessing here how many X’s will be added in 2 generations).

The RX 7900 XT has been sent back.

On Friday AMD announced RX 7700 XT and RX 7800 XT FULL AMD Stage Presentation (RX 7800 XT 16GB & FSR3) | Gamescom 2023 - YouTube and I was thinking to change AMD RX 5700 XT for RX 7800XT but seems that RXT 4070 will be safer choice?

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Tbh, both Nvidia and AMD are underwhelming this generation.

RTX 4070 is on-par with RTX 3080 performance-wise, just more efficient.
So unless you really want Nvidia’s frame generation or play a lot with raytracing or do a lot of streaming (AV1 encoding), there’s no reason why you couldn’t just get a last gen card and save €150.

IMO RX 6800 XT, RTX 3080 (Ti), RX 69(50) XT are still great cards to play DCS on in the same price range or lower than the RTX 4070. Get one if you find a good deal.

RX 6900 XT and RX 6950 XT even outperform the RTX 4070, but with DLSS 2 on the horizon, you may prefer an Nvidia card until AMD can offer significantly better performance.

7800XT looks good on paper,
I’d wait and see actual performance numbers and for the Hyper RX Enabled Drivers that’s supposed to fix latency (We’ll see).

FSR3 will also be a DirectX11 / 12 Driver Level Feature in Q1 next year (vs a Developer enabled feature now).

I bought a 2nd 6800XT for $490 off amazon (the same one I paid $570 for), before they went out of stock.

This one will upgrade my brother from RX580, I’ll also be upgrading his core (likely an entire rebuild) from 990FX/FX8350 to AM4/Ryzen5 5600

But clock for Clock the IPC gain from rDNA2 to rDNA3 is < 10%

I have a Merc319 6800XT, and I can play DCS in VR (with appropriate settings), at 90FrPS Locked w/ the card slightly undervolted.

Flat Screen I have yet to even max it out, I run 60Hz Screens, so I lock all my games at 60Hz, and every game maxed runs fluidly, using less than 40% GPU Utilization.

So extrapolating that, 90Hz 120 Hz should be fine, 144Hz a stretch or reducing some settings.

But seeing the standard issue eyeball can rarely see above 80Hz, I see no point in investing in 120/144Hz.

OMG. What I should buy, RTX 4070 or RX 7800 XT? :slight_smile:

Sapphire Radeon RX 7800 XT Nitro+ Review - Fantastic Overclocking | TechPowerUp

@Freak so, VR is still better on Nvidia?

The RX 7900 XT still has latency issues in VR yes, even after the July driver update with improved VR performance. Probably something to do with the chiplet architecture needing some refinement. This is the first chiplet-based GPU.

The RTX 4070 is architecturally closer to AMD’s RX 6000 series than to the RTX 3000 series though: it has low memory bandwidth and uses an enlarged cache instead. This leads to high power efficiency and performance does not suffer much in most applications.

But I expect that similarly to the RX 6000 series’ Infinity Cache, it will cause reduced performance in high-res VR flight simulators, at least compared to cards like the RTX 3080 (Ti) and 3090.

Also, the RTX 4000 cards are overpriced.

For now, I’d recommend to look for a good deal on a last-gen card: RTX 3080, 3080 Ti, or 3090.

RX 6900 XT or RX 6950 XT can be had really cheaply sometimes too, so may be worth it.

But no, with current drivers and prices I don’t recommend buying either of the cards you mention. Unless you absolutely need stuff like AV1 encoding perhaps…

@Rapier I’m sorry I just noticed I misread your question.

The RX 7800 XT is not a chiplet design so it should not suffer the same problems as the 7900 series.
Looking at that review, it seems like the higher the resolution, the more it outperforms the RTX 4070. That does not bode well for VR.

We have been hearing about DLSS 2 for DCS for a while now, but otherwise I see no reason why the RTX 4070 would be a better fit for VR.

I haven’t found any reports of the RX 7800 XT in DCS VR so there’s only one way to find out if it’s a good fit…

EDIT: I was wrong, see Skatezilla reply below

Glad I read this before thinking about the 7900 in more depth. It seemed appealing at first because it was the only card better than my 3060OC that didn’t cost a month’s rent.

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Who told you that?

7800XT is definitely a GCD+MCD Chiplet design.

You’ve Heard DLSS for DCS, but a version number was never attached to those news articles/blurbs.

Seeing as the 7800XT was just released, I doubt you’d see anything in mainstream reviewers coverage as none of them play DCS, nor use DCS in their roster of benchmarks.

The thing that would help w/ latency is Anti-Lag+ as well as other Specific RDNA3 driver settings.

There are users w/ rDNA3 cards in DCS.

But the Stuttering in VR isnt a DCS Problem it’s an AMD Problem as it is apparent in other titles.

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