cpu Compatibility

[rooai]

Can't I use the i9-13900T on an HP PC elite 800 tower G9?

Is a BIOS update required?

[NonSequitur777 · Accepted solution]

@rooai,

Welcome to our HP Community forum!

Yes, you can technically use/should be able to install an Intel Core i9-13900T on the HP Elite Tower 800 G9, and a BIOS update is indeed required if the desktop was manufactured with an older 12th-generation Intel firmware.

Compatibility Considerations:

1.) Physical Socket Match: The i9-13900T fits the LGA1700 motherboard socket used by the HP Elite G9 series.

2.) Motherboard Chipset Support: The G9's Q670 enterprise chipset supports 12th-gen, 13th-gen and 14th-gen Intel processors natively.

3.) The "T" Variant Limitation: The i9-13900T is a low-power (35-watt) power-optimized processor typically reserved for the ultra-compact HP Elite Mini 800 G9. While it should work in the Tower chassis, installing a low-power "T" series chip in a full-sized desktop tower means you will get significantly less computing performance than the standard 65-watt i9-13900 that HP officially sells with the Tower configuration.

Why the BIOS Update is Mandatory:

1.) Boot Recognition: Motherboards built during the initial 12th-gen rollout cannot recognize or boot a 13th-gen CPU without updated microcode. You must flash the BIOS before removing your old 12th-gen CPU.

2.) Critical Microcode Fixes: Intel 13th and 14th-generation i9 processors have a well-documented hardware instability flaw. You must update the BIOS to the latest version (02.21.00 Rev.A released on February 4th, 2026) in order to ensure HP's integrated Intel microcode patches are active. Running the i9-13900T without these critical system updates risks causing permanent physical damage to the processor over time.

Why Nobody is fitting a "T" processor in the "Tower":

Btw, the reason you will not find public logs of someone installing a "T" variant in the full-sized HP Elite Tower 800 G9 is strictly down to economics and performance. The Tower comes equipped with a large power supply and a massive cooling apparatus designed to handle standard 65-watt to 125-watt processors. Buying a severely power-limited 35-watt "T" chip to put inside a giant case defeats the purpose of buying a Tower to be honest —users upgrading the Tower almost exclusively buy standard high-performance variants such as the i9-13900 or i9-14900.

Kind Regards,

NonSequitur777

[rooai]

Your detailed explanation was really helpful.

Thank you.  Have a great day!

[NonSequitur777]

@rooai,

You're quite welcome and wishing you smooth sailing!

Warm Regards,

NonSequitur777

[rooai]

May I ask one more similar question? Can I use an i5-13600k or i5-14600k CPU in the Elite 800 G9 Tower? Of course, I expect it to run as a non-k processor.

[NonSequitur777]

@rooai,

It would appear so: here is an HP Elite 800 G9 Tower user who fitted an Intel Core i9-13900K: HP Elite Tower 800 G9 Desktop PC Performance Results - UserBenchmark.

Please note that this processor seems to be struggling: "Performing way below expectations (1st percentile)".  I wonder if this has to do -not with the already high "Processor Base Power" 125-watt TDP, but its "Maximum Turbo Power" 253-watt TDP which for sure your motherboard cannot handle.  Both the i5-13600K or i5-14600K have the same 125-watt base TDP and a max 181-watt TDP, which your motherboard still cannot handle.

Unofficially, your motherboard cannot handle anything above 150-watt.  In order to avoid electrical/performance issues with either an i5-13600K or i5-14600K, you must cap the max wattage to your processor to 150-watt.

You do that quite easily with a most useful freeware software program called QuickCPU which I used for my HP Pavilion TP01-3003W upgrade project when I installed an i7-12700KF, also with a 125-watt base TDP and a Maximum Turbo Power TDP of 190-watt.  My PC would crash as soon as it 'crossed' the 150-watt barrier, but QuickCPU fixed that nicely: https://h30434.www3.hp.com/t5/Desktop-Hardware-and-Upgrade-Questions/Upgrading-an-HP-Pavilion-TP01-3....

Kind Regards,

NonSequitur777

[rooai]

Hello. I updated the BIOS on my Elite G9 Tower,

but it still does not recognize the i9-13900T.

I downloaded and installed 02.21.00.Rev.A from the HP website.

After installation, I checked with tools like CPU-Z or HWInfo,

and it displays only as 02.21.00 without Rev.A.

Was the BIOS installed correctly?

[NonSequitur777]

@rooai,

The BIOS update appears to have installed correctly.

On HP systems, “Rev. A” is only the SoftPaq/package revision from HP, not the actual firmware version shown by CPU-Z or HWInfo. Seeing only “02.21.00” is normal after installation.

The more important issue is likely the motherboard System Board ID revision.

For the HP Elite Tower 800 G9, there are multiple board revisions:

• 8AC1 / 89B2 / 89B3 → generally support 13th Gen and newer Intel CPUs
• 894D / 89B4 / 89B5 → early-production boards mainly limited to 12th Gen CPU support

Even with the newest BIOS installed, HP appears to lock CPU microcode support based on the motherboard board ID. So, an early 89B4/89B5 board may still refuse or improperly recognize 13th Gen processors such as the i9-13900T.

This is probably not related to the CPU being a 35 W “T” model. From a hardware standpoint, a lower-power 13900T should be easier to support than a standard i9-13900.

I would recommend checking your motherboard System Board ID in:

• BIOS Setup (F10)
• HP Support Assistant
• or HWiNFO under motherboard information

If your board is 89B4 or 89B5, then the limitation is likely platform/firmware-enforced and may not be fixable with a normal BIOS update.

Kind Regards,

NonSequitur777