I recently upgraded my Dell OptiPlex 990 by installing a 1TB SSD to improve its performance. However, I'm experiencing extremely slow boot times—often taking 5 minutes or even more, with it sometimes not booting at all for over 10 minutes. It starts with a black screen, then shows the Windows logo for another 3 minutes, and finally the spinning circle appears. I've already tried enabling fast boot in the BIOS, unplugging all USB devices, booting in safe mode, and fully powering down the system. The SSD might be set up in RAID mode, and I also have an optical drive connected to the SATA ports and power connectors from the PSU. Could the RAID configuration be causing the boot issue?
3 Answers
First off, it's great that you upgraded to an SSD! Can you let us know which model of SSD you installed? Sometimes specific models can have issues with certain systems.
It might be worth testing your RAM. Try removing all the sticks and insert just one at a time to see if one of them is causing the problem. Sometimes failing RAM can significantly slow boot times.
Okay, thanks! I’ll give that a shot!
If you're comfortable, you could also try installing Windows 10 instead of 11 and see if the issue persists. It might be more compatible with your setup.

It's a Crucial BX500 1TB 3D NAND SATA 2.5-Inch Internal SSD.