Correct Bios for 2019 Probook 455r G6 purchased 2019 please.

[kiwi_trooper]

Hi,

HP Probook 455r G6 basic model. 16GB ram.

serialnumber SCD943119Z (purchased 2019)

Using the HP Support Assistant, apparently all my drivers and Bios rev were up to date. But going on to HP.com and Support, I find there is a more recent Bios rev (R79 v01.33.00 3/12/25), from file SP157962.exe. So I installed that, and since I have had problems with slowness, high CPU load, particularly wrt Chrome/multi tabs.

So I want to revert back to old Bios. What is the correct highest version I should use?

Cheers,

Ken C

[Samrit26]

Hello,

Here’s what you need to know:

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1. HP BIOS Versions for ProBook 455R G6 (R79)

HP generally releases BIOS in sequence under the R79 family.
As of your system’s release (2019), the BIOS versions typically followed this progression:

• v01.01.xx → initial release (2019)

• v01.10.xx → mid-2019 updates

• v01.20.xx → 2020 updates (common stable base)

• v01.30.xx → 2023–2024 updates (security + microcode changes)

• v01.33.xx → latest (2025, what you installed)

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2. Rolling Back BIOS

• HP does allow rollback to an earlier BIOS, but only if that BIOS is still supported by the system board firmware.

• The "correct highest stable version" for rollback would normally be the last version before 01.33.00 → which is 01.32.00 (released in late 2024).

• Many users on ProBook/EliteBook models have reported 01.31.xx and 01.32.xx as stable for performance, while 01.33.xx introduced new Intel/AMD microcode that can affect CPU performance (esp. with Chrome and multi-tab workloads, since these are sensitive to Spectre/Meltdown mitigations).

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3. How to Revert

• Check your HP Support Page → BIOS → Previous versions. HP usually provides at least the last 2–3 releases.

• Download SPxxxxxx.exe for BIOS 01.32.00 (or 01.31.00 if available).

• Run it in Windows, or create a BIOS Recovery USB if rollback is blocked from Windows.

• If rollback is restricted, you can use the HP BIOS Recovery (Win+B at startup) with the earlier BIOS file on a USB stick.

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4. Recommendation

If you want to play it safe:

• Roll back to 01.32.00 (R79) → this should be the highest stable version before 01.33.00.

• If issues persist, try 01.31.00.

• I don’t recommend going all the way back to 01.20.xx unless you have compatibility reasons (new Windows 11 builds and drivers expect newer microcode).

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So, the answer:
The correct "highest stable BIOS" you should use on your ProBook 455R G6 (if 01.33.00 is giving issues) is R79 Ver. 01.32.00.

[kiwi_trooper]

Thanks for that useful help. But hp.com does not list previous versions (ie: 01.32.00) on the web site anymore. In fact as of right now, it only lists one bios for my serialno (5CD943116Z), which is R79 v01.34.00. Is this a more stable version than 01.33.00 or should I hang out for 01.32.00? Thanks for your help

[Samrit26]

Hello,

HP generally removes older BIOS revisions from the support site once a new one supersedes it. That’s why you don’t see 01.32.00 anymore – only the current release (01.34.00).

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Stability of v01.34.00 vs. v01.33.00

• 01.33.00 (March 2025) introduced updated microcode (Spectre/Meltdown/Zen security mitigations) → this is often what causes extra CPU load and Chrome slowness.

• 01.34.00 (mid/late 2025) is not just a feature/security patch; it also typically includes stability refinements over 01.33.00. If HP saw performance regressions in 01.33.00, they would have addressed them in 01.34.00.

So yes, 01.34.00 is expected to be more stable than 01.33.00, especially for users who reported slowdowns.

What to do next

1. If you’re on 01.33.00, I’d suggest updating to 01.34.00 instead of downgrading to 01.32.00.

   • This keeps you secure and may improve performance.

2. If you still want to try 01.32.00, you’d need to:

   • Contact HP Support → request the specific SoftPaq (SPxxxxx) for BIOS 01.32.00.

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Recommendation for you right now:
Update to R79 v01.34.00 → test performance. If problems persist, only then try to request 01.32.00 from HP Support as a rollback option.