Adding SSD to 8900 with clean windows 10 install

andymm,

You can add the sata lll drive and install Windows 10 on it, however,when you add the other hard drive with the windows 10 OS installed that may not work. Once you put the second hard drive in the computer you will need to go into Windows 10 Disk Management to format and activate the drive. Click the links below for information.

Understanding and Troubleshooting Your Hard Drive

http://dell.to/2iAeV4L

Windows 10 Support Options

http://dell.to/2iA6si6

XPS 8900 Drivers, Downloads and Manuals

http://dell.to/2iAhvYu

Drivers Install Order

http://dell.to/2iA9ItX

How to Add A Hard Drive to This PC in Windows 10
http://dell.to/2iAfyeZ

Windows 10 How To Activate New Hard Drives And SSD's Not Showing Up easy!
http://dell.to/2iAjLPG

How to quickly fix a Windows Blue Screen Error caused by changing the SATA mode

http://dell.to/2iAoNf8

Entering System Setup

Ask the user to tap to enter system setup and make changes to the user-definable settings. In case the user has trouble entering setup using this key, advise them to tap the key when the keyboard LEDs first flash.

Menu

Tap when the Dell logo appears, to initiate a one-time boot menu. This menu provides a list of the valid boot devices for the system depending on the following bootable devices in the system:

UEFI Boot
Windows Boot Manager
Other Options
BIOS Setup
Device Configuration
BIOS Flash Update
Diagnostics
Change Boot Mode Settings

This menu is useful if the user attempts to boot to a particular device or to bring up the diagnostics for the system. Using the boot menu does not make any changes to the boot order stored in the setup.

A NOTE indicates important information that helps you make better use of your computer. NOTE:

The default boot mode is set to UEFI and the operating system is installed in the UEFI Mode from the factory. The System will display the following error if the Operating System was installed in UEFI Mode and the Boot Mode has been changed to Legacy or Vice Versa.

Image: No Boot error message due to wrong Boot Mode.
To correct this error, the user needs to change the Boot Mode in the System Setup from Legacy to UEFI Mode. Click here This link opens a new browser window. to access more information on UEFI and to change the UEFI Mode.

Information in bold below May or May not appy to your situation:

OS installation on systems with SSD module.
When reinstalling the OS on the XPS 8900, field service technicians should ensure that they follow these steps to ensure that they can install the OS without any issue:

Ensure SATA Mode is set to RAID or in some systems Intel Smart Response Technology in the setup.
Tap Ctrl+I to enter the RAID BIOS and disable the accelerate option for the SSD.
Initiate the OS reinstall. Follow it up by installing all the drivers including the Intel Rapid Storage Software.
Run the Intel Rapid Storage software through all programs or the taskbar icon.
Click Enable acceleration under the Status or Accelerate menu.

Image: Enable Acceleration.
Select the SSD to be used as a cache device.
Select the size from the SSD to be allocated for the cache memory. A NOTE indicates important information that helps you make better use of your computer. NOTE:

Any remaining space on the SSD may be used for data storage using the simple data single-disk RAID 0 volume that is automatically created.

Select the drive (or RAID volume) to be accelerated. It is highly recommended to accelerate the system volume or system disk for maximum performance.
Select the acceleration mode. By default, Enhanced mode is selected. A NOTE indicates important information that helps you make better use of your computer. NOTE:

Enhanced mode: Acceleration is optimized for data protection.
Maximized mode: Acceleration is optimized for input/output performance.

Image: Acceleration Modes.

Click OK. The page refreshes and reports the new acceleration configuration in the Acceleration View. Your system is now successfully configured with the Intel Smart Response Technology.

Install Windows 10
How to perform a clean installation of Windows

A WARNING indicates either potential damage to hardware or loss of data and tells you how to avoid the problem. WARNING:

If you format a drive partition during installation, any data on the partition will be erased. Be sure to back up any data you want to keep before you begin.
Turn on your PC, insert the DVD or USB flash drive, and then shut down your PC.
Restart your PC, and then press any key to boot from the DVD or USB flash drive.

If you restart your PC and your current version of Windows starts, you might have to open a boot menu or change the boot order in your PC's BIOS or UEFI settings so that your PC boots from the media. To open a boot menu or change the boot order, you'll typically need to press a combination of keys (such as F2, F12, Delete, or Esc) immediately after you turn on your PC. For instructions on changing the boot order for your PC, check the documentation that came with your PC or go to the manufacturer's website.

If changing the boot menu or order doesn't work, try again by signing into Windows, shutting down, and then starting your PC.