Samsung 990 PRO 2TB: Performance Degradation After 7B2QJXD7 Firmware Upgrade - Capacity-Specific Bug?

[SFdrifter]

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.

---

**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

[Memory Product Expert -1]

Hello useroIUpCVJ7VK,

Sorry, maybe I misunderstood, Did your computer manufacturer say that you needed to reinstall windows to turn off VMD?

I personally have a Asus laptop that i turned off VMD mode, my laptop just rebooted a few times and once I was back at my desktop, VMD was off and Samsung magician was working fine.

I also have a desktop with MSI motherboard, VMD was off by default, but I can turn it on without having to reinstall windows.

[useroIUpCVJ7VK]

That was Samsung's advice. Because it's HP that's not an option I have to reinstall Windows to turn it off, or I can do the manual firmware updates. So no reason for me to stick with a company that could fix an issue with an update. Instead, make the customer do it, and gaslight them, and tell them VMD has never worked with Magician. If I were building a gaming machine this wouldn't be an issue. But at least I have learned a lesson. Always go with your gut.

[Memory Product Expert -1]

Hello useroIUpCVJ7VK

Understood, if this is not a Samsung laptop, I think Samsung support would only be able to give general advice, 

But, I would still check with HP to confirm, you'd be surprised but a lot of computer manufactures have easy ways to turn off VMD without reinstalling Windows.

Having to reinstall Windows due to a BIOS setting being turned off was needed back in the older days of windows, but if your using Windows 10 or  11, there are easy ways around this. 

But if HP is not providing any information for this, then I agree that it wouldn't be worth the effort in most cases, especially if your SSD is not having any issues, then doing all of this wouldn't even be necessary 

[useroIUpCVJ7VK]

It won't recognize the drive with it turned off. I mean I've had zero issues with this drive. I normally don't do updates until I see what problems they've caused, When I bought the 990 pro I knew about the degradation problem they were denying and then finally admitted it, and put out a firmware update to fix it. I installed the drive clean install of Windows 11, I went straight to Samsung installed the Magician software it said there was a firmware update and it's worked ever since. I have received updates through there until now. Like I said they could fix they're choosing not to fix it.
If I have to manually do updates from them why should I even keep their software installed?

[Memory Product Expert -1]

Hello useroIUpCVJ7VK,

Well, I would ask the system manufacturer why do your SSDs not show up when VMD mode is off,

Regardless of the issues, since its your computer, you should be able to set the computer to any mode and that should not cause your SSD to stop being detected.
Both of my computers let me use the SSD with VMD off or on.

You should be able to just turn off VMD, let windows do it restart and readjustments, then go to Magician and do the update as needed.

[hafizaameen]

It's always valuable when user feedback helps identify a performance gap. Thankfully, a simple firmware update directly from Samsung can resolve this and restore the drive's incredible speed. You can find the official solution and update tool here:https://semiconductor.samsung.com/consumer-storage/support/tools/

[SFdrifter]

Fantastic!  Samsung quickly resolved the apparent regression with a new firmware release!  "Mission accomplished!"

Oh wait...https://semiconductor.samsung.com/consumer-storage/support/tools/ still shows the 7B2QJXD7 September release that is the focus of my original post.  So nothing's changed.  Dang!

I'm not the only one who's identified this issue...see, for example, this thread from when 7B2QJXD7 was first released, where 4 others note the reduction in random write speeds:  https://www.reddit.com/r/buildapc/comments/1mp8kki/low_random_write_speeds_on_samsung_990_pro_2tb/?e...   

[Memory Product Expert -1]

Hello SFdrifter ,

Does anyone have result performance before and after firmware update? I personally still don't see how the low random write is caused specifically by firmware and nothing else ?

It seems like everyone is pointing the issue towards the firmware, solely based on the fact that the firmware was the last thing that changed. 

But i posted my performance on page 1 of this thread, I have the latest firmware 7B2QJXD7, My drive is also 2TB and I am not seeing the same issue. 

[SFdrifter]

"Does anyone have result performance before and after firmware update?"  Well, one can only hope so.  The difficulty, of course, is that, to my knowledge, there's no way to rollback the firmware version, so there's no way to readily repeat the experiment.

"It seems like everyone is pointing the issue towards the firmware, solely based on the fact that the firmware was the last thing that changed."  Fair enough, but, hey, isn't that the scientific method?

"I am not seeing the same issue."  I understand -- although how much of the drive's capacity is used may also play a part (in my case, it's my system drive with 5 partitions, and total usage is ~55%).  Unfortunately, I'm using Linux, so I can't use Samsung Magician to assess performance -- another variable in assessing this issue.

I repeated my initial post on Anandtech, trying to drum up more data.  My most recent post there provides a little more data as well as the fio commands that I'm using (see https://forums.anandtech.com/threads/samsung-990-pro-2tb-performance-degradation-after-7b2qjxd7-firm...).

Note that the degradation in random write performance that I'm measuring isn't really perceptible -- if I weren't benchmarking after each major change, I wouldn't have noticed anything different.

[niegowic]

I got the same problem 😞 After upgrade to latest firmware it sucks.. it was working much better before upgrade of firmware