How to fix the I/O response lag on WD SN850 2TB SSD drive?
When zooming through the city at high speeds, I noticed these tiny, irritating hitches in the frame pacing that are just unbearable in an open-world game. It turns out the SLC dynamic cache on my WD SN850 2TB was hitting a wall, causing random read speeds to tank from 6600MB/s down to a pathetic 1500-2100MB/s, which spiked engine latency by 2.8-4.2ms. I wasted some time disabling background disk scans, but the frame time variance didn't budge, which was honestly baffling. I eventually dove into Device Manager and bumped the NVMe controller queue depth from 1024 to 2048, then forced the write cache flush policy in Windows performance options. After running CrystalDiskMark, my 4K random reads jumped from 55-68MB/s to 78-92MB/s, and the scene transitions finally stopped hitching. Funnily enough, the system had a weird disk recognition lag at first after the queue depth change, but switching my power plan to High Performance killed that issue instantly. Temperatures stayed steady between 45-58℃ with the heatsink. I ran a full I/O stress test to confirm the response times are now rock steady, with frame generation sitting comfortably at 5.1-6.4ms.
