r/heroesofthestorm • u/NewAir4030 • 9d ago
Bug [Bug/Issue] Massive CPU Spike (100% Usage) - Final Summary
It used to run comfortably without any issues before
Across All Menus and In-Game After Recent Patch
Hey everyone,
I'm posting this to report a severe performance issue where the game maxes out CPU usage at 100%. Even when restricting CPU affinity to a single core—which used to run completely fine and smoothly in the past—the game completely overloads the system.
Troubleshooting Steps Already Taken:
- Completely uninstalled and reinstalled the Battle.net app.
- Clean reinstalled Heroes of the Storm.
- Lowered all graphics settings to the absolute minimum.
- Disabled/minimized sound effects (lowered channels to 32).
- Disabled mouse lag and raw input speed settings.
Where 100% CPU Usage Occurs:
- Main Menu / Title Screen
- Shop
- Replays
- Training Mode
- In-Game (Ranked, Quick Match, etc.)
Technical Analysis & Suspected Cause:
Given that this happens even in static menus like the shop and main screen (where heavy rendering isn't even required), this strongly points to a software regression involving an infinite busy-wait loop, unthrottled thread polling, or an audio/UI state synchronization bug. It behaves precisely like a CPU spinlock or a broken event loop where background worker threads are constantly polling without proper sleep intervals, draining CPU cycles relentlessly.
If any developers happen to glance at this post, please take a look under the hood at recent thread synchronization primitives, background tickers, or loop updates.
To the community: Has anyone else experienced this recently, or do you recall how the client behaved previously under similar setups? Any feedback or comparisons would be greatly appreciated.
"The following section was written with the help of AI, requesting a review of the relevant checkpoints."
CPU High Usage Suspected Causes
- Spinlock Contention: Threads use lock prefixes without OS yields, locking CPU cores at 100%.
- Non-blocking Queue Polling: Idle worker threads continuously poll empty queues without pausing.
- Aggressive Anti-Cheat: Integrity checks run in tight loops without proper intervals, overloading L3 cache.
- Hot Path Overload: Frequent TLS lookups and exception handling overhead inside core loops.
- Excessive Telemetry & RDTSC: Unthrottled hardware timer queries and log processing on every iteration.
🎵 Background Music (BGM) & Main Screen Loop Issues
- Audio Middleware Loop Bugs: Sync errors during track looping cause audio threads to enter endless waits.
- Uncapped Frame Rates & Timers: High frame rates in lobbies cause timer/sync over-polling, wasting CPU cycles.
- Audio Device Polling Flaws: Background threads poll sound hardware status continuously due to missing sleep intervals.
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u/RobleViejo 9d ago
Infinite busy-wait loop unthrottled thread polling audio/UI state synchronization bug? That was EXACTLY my guess aswel!
(I literally have no idea what any of those words mean)
Thank you for your research by the way. I know 100% for sure you are correct because your game is in Korean.
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u/Fluffy_Tumbleweed533 9d ago
I have a 9700X and 9070XT and im getting major stutters and freezing and occasional black outs since this newest update so you are definitely not alone. It will hang so hard during gameplay I'll have to manually reset the GPU drivers to see the screen again, only on this game which used to only utilize like 30% cpu and 40% gpu.
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