Hello,

if I may, which of the 6 variants of the 13900 have you installed ?

The reason a 13rd gen CPU does not work on your machine because you purchased a 12th gen CPU system.  It would come with the earlier motherboard version which being made when 13rd gen CPU did not come out yet.

The same was applied to other models 3660, 5820, 7820, etc.  When it spans for two or more years, different motherboard versions were added to support the release of newer CPUs.  It was also the reason why a replacement motherboard did not fix the issue.  Because Dell support would please you to replace the board but they had to replace it with the same motherboard product number on your system tag, according to warranty term.  Resulting the same, older board won't work with newer CPUs.

When the same workstation model number can support different generation of CPU, so the manual and tech specs were revised to include the newer CPUs. 

I hope these information will help you understand better and not chasing for a problem when it is not there.  A similar upgrade discussion can be view here.

Until someone can confirm, I found that motherboard 05DF4W is compatible with 13th gen CPU.

I don't want to get your hopes up but based on the part number provided for your motherboard, there is a possibility that the board 0DV6DR might work with 13th gen CPU.

You may attempt to install the new CPU again.  To ensure technical compatibility, you may consider to update system to latest BIOS firmware.  After installing the new CPU, perform a CMOS reset.  Then boot system up to see if the new CPU is recognized.

Dell Tech Support didn't identify that there needed to be a newer motherboard to work with a 13th Gen CPU.  To confirm that there are different motherboards between 12th Gen and 13th Gen.  Can an owner of a Precision 3260 with a 13th Gen CPU confirm the motherboard DP/N (Should be near the RAM and CPU

The part number for a unit with a 12th Gen CPU is 0DV6DR

The 13th Gen CPU tested as was a i9-13900 SRMB6BX8071513900 

So after talking to technical support, they dont sell a CPU upgrade and wont confirm what CPU options will work.

I ended up ordering a 3rd party Core i9 12th gen CPU and this works fine in the system

Waiting for the 80w heatsink to arrive so I can take advantage of the increased processing power.

Yep - just found this out also.....bought a 13th i9 to find out it didnt work. Just tried bios 2.6.1 thinking that might work but no luck...just in case anyone else tries this.

I recently purchased a Dell Precision 3260 from the Dell Outlet with the plan to use the system as a portable workstation that I can use when I am on site or at a clients office.  My main workstation is a T7920 which is upgraded to process 3d scans and photogrammetry data sets that require serious computation power (CPU and GPU).  

I Precision 3260 system that I purchased had a 12th Gen i3 CPU with the intent to upgrade the system to an 13th Gen i9 with additional RAM to handle the workload.  prior to the purchase I had checked the Dell Support page that listed the 13th Gen i9-13900 CPU as being supported (Data sheet and user manual), the website also has 3260 systems for sale with the i9-13900 CPU.  Having checked this, I ordered a 13th Gen Core i9-13900 CPU from a reputable seller here in AUS and installed the upgraded CPU.

The system now boots to a BIOS message stating that the 13th Gen CPU is not supported, I have been on the phone with tech support and they don't understand why 13th Gen i9 is not working and organised a replacement motherboard in case the one supplied with the unit had an issue.  

The laptop came with an 8th Gen Intel Core i7 CPU, but I decided to upgrade it to a more powerful 9th Gen Intel Core i9 processor for better performance. I did my research on the Dell support page, and it clearly listed compatibility with 9th Gen CPUs for my laptop model. I purchased the Core i9 processor from a reputable source and installed it. Upon booting up, I received an error message indicating that the CPU was not supported.