i have an HP compaq dc 7800 convertible minitower and i want to replace its cpu

[Ahmed147]

hello there 

i have an HP compaq dc 7800 convertible minitower and i want to replace the core 2 duo e6550 inisde it with core 2 quad q9400 so iwant to know if my case is compatible with this processor or not . 

also i want to know if i will have to update the bios or not

[Paul_Tikkanen]

Hi:

Below is the link to the HP Quickspecs for the dc7800.

HP Compaq dc7800 Business PC (nordykassociates.com)

The supported processors can be found on page 9.

You will probably have to update the BIOS and/or the microcode to support a quad core processor.

The Q9400 is not supported according to the list, but it may work.

If you have to buy the Q9400, I strongly recommend that you buy one of the Intel quad core processors officially supported instead.

[NonSequitur777]

@Ahmed147,

Welcome to our HP User Forum!

In addition to the processors as referenced by @Paul_Tikkanen, you can upgrade your HP Compaq dc7800 Convertible Minitower with the Core 2 Quad Q9400, as well as these dc7800 compatible processors: Core 2 Quad Q9650, Core 2 Quad Q9500 and the Core 2 Quad Q9450 as per actual dc7800 CMT Users as verified here: UserBenchmark: HP Compaq dc7800 Convertible Minitower Compatible Components -all fitted with the HP OEM dc7800 CMT "Hewlett-Packard 0AACh" motherboards.

The most up-to-date BIOS version is 786F1 v1.35 (even though it registers as "BIOS Date 20151023") as found here: https://support.hp.com/us-en/drivers/selfservice/hp-compaq-dc7800-convertible-minitower-pc/3459240.

If you need a tutorial how to upgrade your BIOS, look no further than here ("How to Update HP Compaq DC7800 BIOS Firmware Using DOS bootable USB Drive or In Bios Settings"): https://youtu.be/GmeqFTnL7_s.

BTW: you can also upgrade your OS to Windows 10 -or even Windows 11 as per @Paul_Tikkanen: Re: CPU upgrade for windows 11 - HP Support Community - 8427022.

Hope this was helpful.

Kind Regards,

NonSequitur777

[Paul_Tikkanen]

Hi, @Ahmed147 

Yes, W11 runs just fine on a dc7800 CMT.

I have W11 Pro 64 bit running on my dc7800 CMT, E8300, 250 GB SSD, 8 GB DDR2-800 memory and a Radeon HD 6570 GPU.

Works great.

I used the W7 audio driver and the W7 HECI and AMT drivers for the PCI Simple Comms Controller and PCI Serial port that will need drivers.

The W7 audio driver works better than the generic one W11 installs.

[Ahmed147]

so can i run it without any proplems ?

or if i found supported cpu from the list would i better think again ?

and thanks for guys ^^

[Paul_Tikkanen]

You're very welcome.

There are no W11-supported processors you can install in a dc7800.

Not only are none of the processors supported, the dc7800 does not have a UEFI BIOS, nor does it support Secure Boot, nor does it have a TPM 2.0 security device.

You can run W11 on your PC right now.

But first you would have to get the free upgrade from W7 to W10 by clicking on the blue Update Now button at the link below.

Download Windows 10 (microsoft.com)

Then you can use this hack to upgrade to W11.

https://dongknows.com/steps-for-windows-11-upgrade-on-unsupported-hardware/ 

Before you try to upgrade to Windows 10 or W11, I recommend that you make a system image of your current W10 installation prior to updating to W11, so you can easily reinstall W10 in the future.  I used the free Macrium Reflect software to do that, under the Backup at Home section. 

Along with the system image, make sure you create the bootable DVD or USB rescue drive you boot from to access the system image stored on your portable hard drive.

Macrium Software | Reflect Free Edition

[NonSequitur777]

@Ahmed147,

Assuming you live in the US -but regardless, if you choose to acquire a Q9650, Q9550, Q9500 or Q9400, they are very affordable online, such as through eBay:

1.) Q9650 starting at $40: https://www.ebay.com/itm/195183942549?epid=15029958281&hash=item2d71de9b95:g:EN4AAOSw36NivyAs

2.) Q9550 starting at $20: https://www.ebay.com/sch/i.html?_from=R40&_nkw=q9550&_sacat=0&LH_TitleDesc=0&_sop=15&LH_PrefLoc=1&rt...

3.) Q9500 starting at $15: Intel Core 2 Quad Q9500 2.83Ghz/6M/1333/05A LGA775 CPU Processor SLGZ4 J6-5 | eBay

4.) Q9400 starting at $9: core 2 quad q9400: Search Result | eBay

Hope this was helpful.

Kind Regards,

NonSequitur777

[Ahmed147]

so if i will upgrade the cpu to higher one should i install bios update as in the video you sent ?

[Paul_Tikkanen]

Hi:

I recommend updating the BIOS if your PC is not at v1.32.

The latest BIOS update is v1.35

If you update the BIOS, install the Quad core processor and you still get an 1801 microcode error, here is what you need to do to install the Microcode update. 

Solved: How to fix "1801-Microcode Update Error" in HP tower desktop... - HP Support Community - 617...

[Clubsoda]

Has any tried upgrading the CPU using a quad core2 extreme cpu? QX9770?