Dell Optiplex 790 Maximum CPU

@JOcean 

As I've already stated, this PC came with Windows 7. But when I decided to update to Windows 10 Pro, It passed the compatibility check. I even did a fresh installation to make sure, & it was still able to install Windows 10 without any problems. I even bypassed the Windows 11 installation & so far, no issues or malfunctions have occurred as of now. So I don't understand why Dell decided to put it as Windows 10 incompatible On the Microsoft website, read the bolded words. And so far, there aren't any problems occurring. On the Microsoft page, it stated "If you proceed with installing Windows 11, your PC will no longer be supported and won't be entitled to receive updates. Damages to your PC due to lack of compatibility aren't covered under the manufacturer warranty." 

To begin with, as you know, that is quite an old CPU and Dell did not even list the 790 as Windows 10 compatible. That obviously does not mean you cannot run Windows 10 or bypass the requirements for Windows 11. Now this support page lists the systems that can be updated to TPM 2.0 and the 790 is not on the list. But to answer your question, no there is no way to update the system to have Secure Boot and TPM 2.0. and you cannot upgrade to a Gen 8 CPU which is the oldest generation that MS is supporting on Windows 11.

@bradthetechnut I am using the DT Model Dell OptiPlex

That's granted you don't have the USFF.

Just because Dell decided that the system was not Windows 10 compatible does not mean it would not run Windows 10. I have a Latitude E6420 that was also listed by Dell as not compatible with Windows 10 but it runs like a charm. Sorry if my statement mislead you.

As for Windows 11, it was not Dell's decision to list your system as incompatible with Windows 11. That was entirely a Microsoft decision. The system requirements have left a number of manufacturers having to remove Windows 11 support for their older systems not meeting the MS requirements. Now as for the MS statement. MS has threatened to remove support and updates for any unsupported system that has Windows 11 installed. As of this date that has not happened and it may not ever happen. But the possibility exists that one day MS will withdraw support and updates and may in fact block those systems from running Windows 11 in the future. It's MS world and we just live in it.

Yah, funny how MS listed minimum requirements for Win10 as 1.0ghz CPU and 1GB RAM.  Those will definitely run it slower.  4GB RAM is ok, but 8GB runs it faster, which you have.

@JOcean knows your 790 can run Win10; and Win11 with checks bypassed.  Just due to the age of those systems, Dell didn't validate the system for those OS'.

I had Win10 on my 755 and when we had Rockstar speedstep, he had a GX620 running Win10 stating that's as far back as it can go with an Optiplex.

I was so used to seeing some speedstep posts, I just remembered it might be false that Win10 can only go as far back as a GX620.

The laundromat here in town as 2 old PC's for public use - a 380 SFF and 760 or 780 SFF, both with Win10.  I tested them out a ways back and the 380 was herky-jerky just for the internet.

Dell probably doesn't care any more about system requirements for the Dell OptiPlex 790 since it is such an old model and they discontinued it. So that's probably why they say that the Dell OptiPlex 790 isn't compatible with Windows 10/11

I have a Dell Optiplex 790 and I put an i7 2600 CPU in it but the computer does not give
mean image. They told me that it is the model of the motherboard that is disabled and that
the i7 2600 is compatible but it has more power than what the motherboard supports in video and 
that the onlyway to get an image is to buy a video card, is that correct? or the cpu 
is flat out bad since my computer turns on and gives an image with the cpu it had before

I think you ended up with a bad CPU.  There has been no such thing as a 790 MB that won't take the i7-2600 that I know of.  Exception is the USFF model doesn't take 95w CPU's.

I attached the 790 Tech Guide.

@bradthetechnut​ 

@AndiB10​ 

Which is probably why Dell limited the blue PCIe slot to 35w in the 790 (ref. Tech Guide). However, the 260w PSU in the MT can still handle a 75w card and the SFF and DT PSU's can easily handle a 53w RX 6400.  PSU wattages are in the Tech Guide.  As for "no chance of finding a decent one that is less than 50w," there's the 30w GT 1030 GDDR5.  And of course, there's always the "outside of spec" and not Dell recommended YT videos of 75w cards being ran in DT and SFF models.

@ AndiB10 ,yo tengo la misma pc dell optiplex 790 de formato DT y le e puesto un i7 2600 + una gpu adm xt 580 8gb ram 32 gb de ram y windows 10 hasta ahora todo bien ,solo que hice actualizaciones en el gabinete y agregué 6 ventiladores de 8cm y 3 de 4 cm para una mejor refrigeración y un disco duro de 1t formato ssd ,he logrado hasta reproducir juegos como warzone 3 resugimiento, a 60 y 75 fps ,espero que les ayude esto ...obvio no la uso para jugar pero tenia que probar jjj ,detalle aumente la fuente a una de 5000w formato TX que es un formato pequeño ok otra cosa esta con luces argb y no son pocas