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 INVOLVED

I'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.

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**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)

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**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!)

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**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)

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**TEMPERATURE COMPARISON:**
- 2TB (Problem): 113°F / 45°C (elevated)
- 4TB (Normal): 87°F / 31°C (normal)

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**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.).

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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.

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**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