Mortal Shell II Runs Fast but Stutters Anyway: The Traversal Hitch, the DX12 Crash, and What to Set Before August 20

On an RTX 5090 at native 4K and Very High settings, Mortal Shell II’s open beta pushed past 90 FPS in most of the map, and still didn’t feel smooth. That gap between the frame counter and the way the game feels in your hands is the whole story of this launch, and it is exactly why a Mortal Shell 2 stutter fix is the first thing beta players went looking for. The frames are there. The frame pacing is not.

Cold Symmetry’s sequel launches August 20, 2026 on Steam, published by Playstack and built on Unreal Engine 5. The original Mortal Shell was a tight, deliberate soulslike. The sequel trades the stamina bar for faster combat, opens up an explorable world with 60-plus dungeons, and carries all of UE5’s rendering baggage along with it. The open beta gave us a clear look at what that baggage costs, and most of it is fixable on your end before the full game unlocks.

Here is what the beta actually revealed, and what to change first.

What the open beta showed on real hardware

The numbers were genuinely good. Digital Foundry-style testing on an RTX 5090 landed over 90 FPS at native 4K with Very High settings across most of the game, dropping to around 64 FPS in the most demanding areas, and climbing to roughly 100 FPS once DLSS 4 Quality mode was switched on. Those are strong figures for a modern UE5 title rendering at native 4K.

The listed minimum specs are reasonable too: an Intel Core i7-10700K or Ryzen 5 3600, an RTX 2060 SUPER or RX 6600, 16 GB of RAM, and an SSD. Nothing on that list is exotic in 2026. A mid-range rig from three or four years ago clears the bar.

So the problem was never raw throughput. Reviewers and beta players hit three distinct issues: traversal stutter that showed up even at 90-plus FPS, hard crashes tied to the DirectX 12 pipeline, and a memory leak that made long sessions progressively worse. None of those are solved by buying a faster card. They are solved by understanding what UE5 is doing and getting ahead of it.

Traversal stutter and shader stutter are two different problems

This is the single most useful thing to understand about any Unreal Engine 5 game, Mortal Shell II included. There are two separate hitches that both look like “stutter,” and they have completely different causes and fixes.

The first is shader compilation stutter. A pipeline state object, or PSO, is the compiled bundle of shaders plus render state the GPU needs to draw a given effect. When the engine hits an effect it hasn’t compiled yet, it stops and compiles it right then, and everything freezes for a beat. Epic’s own engineering team has written about this openly: the fix is PSO precaching, where the engine compiles those states ahead of time at load or spawn instead of mid-fight. Beta players reported the game crashing during the “shaders loading” step, which is precisely this system doing its work up front.

The second is traversal stutter, and this is the one the RTX 5090 couldn’t outrun. Traversal and streaming hitches come from the engine loading assets as you move through the world: new geometry, new textures, new dungeon rooms streaming in. Epic distinguishes these two classes explicitly because the fixes are different. PSO precaching does nothing for traversal hitches, and faster shader compilation does nothing for streaming stalls.

For Mortal Shell II specifically, that means two habits. Let the “compiling shaders” screen finish every single time, especially after a patch or a GPU driver update, because that pass rebuilds the PSO cache and skipping it guarantees stutter later. And for the traversal side, keep the game installed on your fastest SSD and give the streaming system RAM headroom by closing everything else. If you have run into shader cache trouble before, the same principles that fixed Space Marine 2’s shader compilation stutter apply here almost line for line.

The DirectX 12 crash and the DX11 launch flag

The most common beta-breaking bug was not a stutter at all. It was a hard crash, usually reported as a fatal error or a memory access violation, and it traced back to UE5’s DirectX 12 pipeline being unstable on this build.

The workaround that beta players found most reliable was forcing the game into DirectX 11. Right-click Mortal Shell II in your Steam library, choose Properties, and in Launch Options type:

-dx11

That bypasses the DX12 memory crash entirely on machines where it triggers. It is a blunt instrument, and DX11 can leave a little performance on the table compared to a healthy DX12 path, but a game that runs at 70 FPS beats one that crashes to desktop every twenty minutes.

Two more stability tweaks stacked well with this. Disabling the Steam and Discord overlays reduced launch crashes noticeably, because overlay hooks inject into the render pipeline and UE5’s DX12 layer did not tolerate them cleanly in the beta. And turning off Control Flow Guard for the game executable, through Windows Security under Exploit Protection then Program Settings, resolved a class of access-violation crashes for some players. Add the .exe, toggle Control Flow Guard off for that entry only, and leave the system-wide setting alone.

If the crashes started right after you updated your GPU driver rather than after a game patch, roll the driver back before you assume the game is at fault. That distinction matters, and it is the same troubleshooting logic behind the NVIDIA 610 driver stutter fixes from earlier this year.

Settings that bought the most performance in the beta

You do not need to drop everything to Low. A few targeted changes recovered most of the headroom without gutting the way the game looks.

• Volumetric Fog and Clouds to Medium. This alone freed up roughly 15 percent of GPU overhead in the beta, with a visual difference you have to pause and hunt for. It is the best single trade in the menu.
• Shadow Quality to High, not Ultra. Ultra shadows compute fine detail on debris and rubble you will never notice while you are reading an enemy’s wind-up. High looks the same in motion and costs meaningfully less.
• DLSS or FSR set to Balanced. Quality mode looks marginally sharper, but Balanced buys a real frame-time cushion, and on a game already fighting frame pacing, that cushion is worth more than the last sliver of sharpness.
• Frame Generation off if you see ghosting or micro-stutter. Multi-Frame Gen is supported, and it inflates the frame counter beautifully, but generated frames on top of an already inconsistent frame time can make the stutter feel worse, not better. Turn it off, confirm the base experience is smooth, then decide if you want it back.

Run through those four before you touch anything else. Together they turned the beta from “high FPS that feels choppy” into something closer to locked for most testers.

The memory leak, and why hour three felt worse than hour one

Several beta players noticed the same pattern: the game ran fine at the start of a session and got choppier the longer they played, without loading a new area or changing settings. That is the signature of a memory leak, where the game gradually holds onto memory it should have released, until the system starts paging and stutter creeps in.

You cannot patch a leak from your side, and this one is Cold Symmetry’s to fix before or shortly after launch. What you can do is manage around it. If a long session starts to degrade, save and fully restart the game rather than reloading a checkpoint, because a restart is what actually reclaims the leaked memory. Keeping other memory-hungry apps closed also delays the point where the leak starts to bite, since it leaves more physical RAM before the system falls back to the page file. Browsers with a dozen tabs and Electron chat apps are the usual culprits, and clearing them out is the same move that helps in any game where background processes are quietly eating your frames.

Leave ray tracing off, because it does nothing right now

One beta finding saves you a decision: ray tracing was broken. Testers reported the game looked and performed identically with the setting on or off, meaning it was either not wired up in the beta build or silently failing. There is no reason to eat the performance cost of a feature that produces no visible result. Leave it off at launch and revisit it only if a patch note specifically says ray tracing now works.

Where your lag is actually coming from

Everything above is local. Traversal stutter, shader compilation, the DX12 crash, the memory leak: those live on your PC, and no amount of network tuning touches them. It is worth being honest about that, because plenty of “fix your lag” advice blurs the line and sells you a network tool for a rendering problem.

Here is the clean split. If your frame counter is high but the image hitches, that is a local frame-pacing issue, and you fix it with the settings and workarounds above. If your frame counter is fine but your character rubberbands, teleports, or your inputs land late in an online session, that is latency, and that is where network routing earns its keep. Mortal Shell II is built around single-player combat, so most of what you will fight is local. But if you also live in online shooters or co-op titles, a mistuned route between you and the server is a real and separate problem, and it is worth diagnosing properly rather than guessing. Our guide on why your ping is high and how to actually drop it walks through that side.

A service like WTFast exists for exactly that second category. It reroutes your game traffic across a private network of optimized relays, and on a bad ISP path it can shave real milliseconds and smooth out packet loss. It will not do a thing for a UE5 traversal hitch, and I would rather tell you that than pretend otherwise. But if your problem is genuinely the connection, it is the fastest test there is.

What to do before August 20

The beta told us where the sharp edges are, so you can walk into launch day already ahead of them. Update to the latest stable GPU driver and, if the game ships with day-one driver support, install that build. Put Mortal Shell II on your fastest SSD. Set Volumetric effects to Medium, Shadows to High, upscaling to Balanced, and leave Frame Generation and ray tracing off until you have confirmed a smooth baseline. Keep the -dx11 launch flag in your back pocket in case the DX12 crash follows the beta into release. And let the shader compile screen finish every time, no matter how much you want to skip it.

Do that, and the 90-plus FPS the hardware is clearly capable of will actually feel like 90 FPS. The frames were never the problem. The pacing was, and pacing is the part you can get in front of.

For the wider pattern behind all of this, the Windows 11 low latency profile breakdown covers the system-level settings that help every UE5 release, not just this one. Launch day is a week and a half out. There is time to be ready.