topic Samsung 990 PRO 2TB: Performance Degradation After 7B2QJXD7 Firmware Upgrade - Capacity-Specific Bug? in Monitors and Memory

topic Samsung 990 PRO 2TB: Performance Degradation After 7B2QJXD7 Firmware Upgrade - Capacity-Specific Bug? in Monitors and Memory https://us.community.samsung.com/t5/Monitors-and-Memory/Samsung-990-PRO-2TB-Performance-Degradation-After-7B2QJXD7/m-p/3391351#M17442 PLEASE NOTE THAT THIS FIRST POST WAS MOSTLY INCORRECT -- I MISINTERPRETED SLC CACHE EXHAUSTION FOR POOR PERFORMANCE; I DO NOT BELIEVE THERE IS A FIRMWARE BUG INVOLVEDI'm reporting an apparently capacity-specific firmware bug affecting Samsung 990 PRO 2TB drives after updating to firmware 7B2QJXD7. My 4TB 990 PRO with identical firmware performs normally.---**AFFECTED DRIVE:** - Model: Samsung SSD 990 PRO with Heatsink 2TB (used as system drive with 5 partitions) - Serial: S7DRNJ0XC08579H - Firmware: 7B2QJXD7 (upgraded from 4B2QJXD7) - System: Arch Linux, AMD Ryzen 9 9900X**COMPARISON DRIVE (NORMAL):** - Model: Samsung SSD 990 PRO 4TB (used as data drive with 1 partition) - Serial: S7DSNJ0X912378T - Firmware: 7B2QJXD7 (upgraded simultaneously with the 2TB SSD)---**PERFORMANCE DEGRADATION (FIO BENCHMARKS):****2TB Drive - BEFORE firmware upgrade, using 4B2QJXD7:** ✓ Sequential Write: 6,650 MB/s ✓ Random Write: 4,436 MB/s (1,135K IOPS) ✓ Sequential Read: 6,650 MB/s ✓ Random Read: 2,970 MB/s (760K IOPS)**2TB Drive - AFTER firmware upgrade, using 7B2QJXD7:** xx  Sequential Write: 1,478-3,691 MB/s (45-78% LOSS) xx  Random Write: 1,375-1,460 MB/s (68-70% LOSS) ← CRITICAL ✓  Sequential Read: 6,752-7,007 MB/s (normal) xx  Random Read: 2,369-2,582 MB/s (13-20% loss)**4TB Drive - AFTER firmware 7B2QJXD7:** ✓ Sequential Write: 6,577 MB/s (NORMAL) ✓ Random Write: 4,435 MB/s (NORMAL - matches 2TB baseline!) ✓ Sequential Read: 6,687 MB/s (NORMAL) ✓ Random Read: 4,594 MB/s (EXCELLENT - better than 2TB baseline!)---**TESTING METHODOLOGY:**To isolate the issue, I performed extensive testing:1. Tested across multiple partitions (root, home, data) 2. Tested from Live USB (eliminating OS activity) 3. Tested both drives with identical parameters 4. Monitored temperatures during tests**KEY FINDINGS:** - Performance degradation occurs on ALL partitions of 2TB drive - Live USB testing (no OS) still shows degraded performance - 2TB drive runs 26°F hotter than 4TB (113°F vs 87°F) - Higher temp suggests excessive write amplification? - 4TB drive with SAME firmware performs perfectly - Both drives updated simultaneously - Both have similar write endurance (~22-23TB)---**TEMPERATURE COMPARISON:** - 2TB (Problem): 113°F / 45°C (elevated) - 4TB (Normal): 87°F / 31°C (normal)---**POSSIBLE IMPLICATIONS**Is this a **capacity-specific firmware regression** affecting 2TB 990 PRO models?  Does the 7B2QJXD7 firmware have different code paths for different capacities, and does the 2TB implementation have a critical bug in random I/O handling?The elevated temperature on the 2TB drive suggests the firmware is causing excessive internal operations (write amplification, garbage collection, etc.).---Dear Samsung -- 1. Can you please confirm this capacity-specific bug? 2. Can you investigate why 2TB apparently differs from 4TB implementation? 3. Can you provide a firmware fix (8B2QJXD7) or rollback capability? 4. Can you provide guidance for affected users?**Has anyone else experienced this after updating 2TB 990 PRO to 7B2QJXD7?**I have detailed benchmark logs, SMART data, and test results available as requested.---**System Details:** - OS: Arch Linux (kernel 6.x) - Motherboard: AsRock x870e Taichi - Testing Tool: fio 3.39 - Test Parameters: libaio, direct I/O, various block sizes Thu, 20 Nov 2025 07:18:07 GMT SFdrifter 2025-11-20T07:18:07Z