I tried to downgrade the BIOS to version 0484 from USB using recovery mode with my old E6700 installed, but all I get is a blank screen. I also attempted to downgrade to version 0517 using Iflash2 from a bootable USB drive, but it failed. I can still get into the BIOS upon startup with either cpu installed with BIOS version 0572, but the OS will only install with the E6700 cpu installed.
All very old, and unsupported. I cannot find a compatibility list that says the Q9560 is supported on your board. Yes,, you say the bios detects it. But, that does not mean anything if the bios does not support it.
If you have tried the latest bios, and the q9560 is known good, then I would have to start thinking that it is not supported by the bios. Otherwise, the q9560 is bad.
With such vintage products, I would not waste my time trying to make them work.
Thank you for your reply. This web page lists it as being supported, along with some Xeon cpu's. http://www.cpu-upgrade.com/mb-Intel/DP35DP.html
With BIOS version 0267 and the Q9650, I could install an OS, but the BIOS was detecting the cpu to be 2.0GHz instead of 3.0GHz. After the BIOS upgrade to 0572, the cpu was correctly detected at 3.0 GHz, but I could not install the OS.
This thread suggests that the Q9560 works with the previous BIOS (v. 0517), but not the latest (v. 0572). https://forums.intel.com/s/question/0D70P0000068ZoISAU/dp35dp-and-q9650-bios-incompatibility-issue?l... However, I tried downgrading the BIOS as this poster did but was not successful. It is looking like I am stuck with v.0572.
I realize this is old and unsupported hardware, but it is more than adequate for my requirements if I can make it work.