For those who bought the mid-tier XPS 15 but plan to swap out the 32 GB SSD, I'm including commentary I've read related to this action. I don't own the mid-tier and thus have little motivation to read through this section in detail. I encourage a wiki visitor to take ownership of this section and flesh it out/clean it up!
Please note that to swap out the SSD or anything else inside the XPS, you will need a T5 (torx) screwdriver. Note that at least one user has commented that they are easy to strip out (i.e., the heads are a little soft) and that you should take care to ensure full engagement between the driver head and the screw head before twisting. Also, as noted in the FAQ, consider investing in a quality torx screwdriver; their sharper tines typically result in better screw engagement and a lower risk of slippage/strippage. Odds are good that if you're spending $12 or more for a single T5 screw driver that it is machined from a high quality alloy and will perform well. Manufacturers producing these include Wiha, Witte, Bondhus, SwissGrip, and Wera, among others.
If you wish to use your mSATA SSD as an independent device (i.e. not as a cache unit for your 2.5" unit), be sure to switch the SATA mode in the BIOS to AHCI rather than Intel Smart Response. It is possible to make this change without having to reinstall Windows (see http://en.community.dell.com/support-forums/laptop/f/3518/t/19532474 ), but in order to maximize your changes, BEFORE making this BIOS change, go into the Intel Rapid Storage application in Windows and disable Acceleration (aka Smart Response). Then also disable Rapid Start if you have it enabled, either in the BIOS or in the Intel Rapid Start application.
The following text is copied verbatim (without permission) from seancho's post to the user forum on NotebookCheck on 09 November 2013:
For those of you opting for the smaller battery + HDD, I just upgraded the small 32gb msata to a 256gb boot drive. It's a bit of a pain. A few notes from my day today that may save someone some grief..
- 32gb msata is raided to the 1tb hdd. You have to de-raid them in bios before you begin, or bad things happen when you try to upgrade. : ) Make sure sata mode is set to ahci before you start.
- Tear-down guide is in the owners manual on the dell site. Swapping msata is pretty simple if you've done similar stuff. Bottom pops off after removing several T5 torx screws and releasing tabs around the carbon fiber bottom with a plastic pry tool, or guitar pick.
- You don't have to remove the battery. Just carefully disconnect the power connector. Then remove the ribbon cable over the msata.
- Dell oem windows 8.1 key isn't written anywhere on the machine. You have to use a program or script to find it.
- Dell oem key cannot be used to download Windows 8.1 using Microsoft's tool. Torrents are your friend.
- Some Windows 8.1 ISOs only install either Core or Pro (though others can install either one). Make sure to choose the correct ISO for the version of Windows 8.1 that shipped with your system (probably Core unless you ordered your system through a Business store.)
- Follow this guide to create UEFI-compatible boot media from the ISO.
- Press F12 during startup to enter the boot device selection menu. If you have issues, see Cannot Boot from USB.
- W8.1 installer text is hilariously small in 1800p. Get a magnifying glass if your eyesight isn't good.
- All the latest drivers and bios update are on the dell site.
(In response to a query about whether one might streamline the process with Clonezilla, Seancho responded with the following:)
As shipped, the 32gb drive is a cache, only. You can't even see it in windows until you turn off raid. Anyway there's nothing on it to clone. Windows is on the HDD. I don't think you could clone HDD to msata either. Windows configures itself differently on SSDs than HDDs.
(Again, taken without permission and printed verbatim from a post by user Woodgypsy on 09 November 2013 to NotebookCheck)
Technically, you don't have to reinstall windows. Many of the recent cloning software are SSD aware, so they will automatically fix disc alignment as it goes. UEFI/GPT of newer laptops make it difficult to clone -- but some software (such as the one made by Paragon) are supposed to be able to handle them fine. Paragon is coming out is the version that supports Windows 8.1 soon, I believe. There are not much bloatware aside from Mcafee.
At the default configuration, 32gb SSD is set up as Intel RST cache. You will have to first disable Intel RST on Windows, then change it to AHCI on BIOS afterward. Afterward, I imagine you can put a new mSata fine.
(As before, the following is taken without permission and reproduced verbatim from a post by user Moda on 10 November 2013 to NotebookCheck)
You're best going with as big a drive as your budget can afford. You can get MSATA SSDs from 32gb -> 1Tb. To be honest, 120/128gb is the probably the smallest i'd go. ~250/256gb is probably the best bang for buck at the moment. For SSDs to perform at peak function they need to have at least 20% free (for TRIM and other garbage collection technologies to work properly.... roughly). I can tell you now, the 256GB SSD I have in my PC right now, is using 70gb. That is W8.1+PhotoshopCC/Lightroom5/PremiereCC/IllustratorCC/IndesignCC/AuditionCC/AcrobatPro+Office2010+iTunes/Browsers/etc+AutoCADInventor. I have Steam and all my games installed on a 2nd SSD (~120gb out of 256gb, I'm not running them in RAID0 because they're different brands etc), and I have my documents/photos/everything else stored on a 2x2tb RAID0 array.
So that being said, you could go with a 120gb and be able to have most stuff installed, but you'd be pushing it.
You can install programs on whatever drive you want. It just requires a bit more management etc. You can run some trickery to get windows to use a secondary drive as the users drive.
Nate Finch's Notes
(original content dated 10 November 2013, Nate Finch gives approval for reproduction however you want as of Nov 17, 2014)
I'd recommend at least 200 gigs. 128 might be fine if you know you won't install much software (like, you're not a gamer, engineer, or programmer).
You can install stuff on a second drive, however, some things just have to be on the OS disk (usually the installer will take care of that itself, though it's not unheard of for software to malfunction when installed on a different drive.. but that should be rare enough not to worry about until it happens).
One thing that you can do is move My Documents, My Pictures, etc to the 1TB drive. There's a setting for it, don't just manually move it. I forget where, but Google will tell you.
As for what to buy, the Mushkin Atlas series gets good reviews. Here's a link to newegg, one of the best places to buy computer parts (you can use their prices as a benchmark of "best price you're likely to get" if nothing else): Newegg.com - Computer Hardware, Hard Drives, SSDs, Internal SSDs, mSATA
Quick rundown on SSDs: 4k random read speed is what makes booting and starting applications fast. Sequential read & write speed is what makes copying huge files fast. Generally 90,000 IOPS is the top of the line for 4k read, and 550MB/s is the top sequential read. 70,000 and 400 for those values is totally fine and normal.
(stolen content disclaimer as above, dated 13 November 2013)
If this is stuff you're not comfortably doing now and then it's easy to end up with a "bricked" machine. My sequence below keeps the original HDD safely un-altered until the new OS is happy in place so that reversion is simpy changing the BIOS HDD interface mode back to "Intel" mode, restoring the HDD as the boot-first option, and reconnecting the HDD.
1. deactivate and uninstall all Intel Rapid drivers, this decouples the HDD form the SSD caching and is required
2. Reboot the system, verify that all is ok
3. Create a backup IMAGE of the system using the Windows Recovery tools (typically to a USB HDD), also allow it to create a recovery disc (one you can boot from in the optical drive)
4. With the recovery disc in the optical drive, reboot the machine. Tap the F12 key to get the boot menu and select the optical device, verify that you can get in to the repair/restore functionality (but don't bother doing so yet).
5. Shut down the machine
6. Remove the bottom of the case and swap out your mSATA SSD drives, button it back up. The Users Manual Dell has posted has info to guide you on this part.
7. If you want to be REALLY PARANOID you could at this time disconnect and remove the HDD from the system to guarantee no changes on it or restoration errors.
8. With the recovery disc in the optical drive, boot up the machine, tap the F2 key to get into the BIOS settings
9. Find and change the drive mode from Intel to AHCI (note:this will now prevent the HDD image from booting, to allow the HDD to boot you'll need to change the setting back)
10. Verify that the boot-order setup is such that the mSATA comes before the HDD
11. save/exit settings, tap f12 key to get the boot selection menu, and boot from the optical drive
12. Go in to the repair/restore functionality and use the recovery tools to restore your system image from the backup onto the new mSATA. If you have your HDD still in and active be VERY CAREFUL to pick the mSATA.
13. Once the restore completes successfully shut down the system, disconnect the USB drive, and boot up from the mSATA.
There may or may not be idiosyncracies to deal with. Windows gets it's fingers into things in weird ways if you ask me.
You will probably want to do the follow-on work with the Disk Utility to make sure your partitions are using the whole drive.
How to move windows 7 to a new or larger hard drive using Backup and Restore
14. Once you have resolved all idiosyncracies and such, shut the machine back down, pop the case off, and reconnect the HDD
15. Button-up, boot up, and then go in to the Disk Utility to delete all partitions off the HDD (even the 'system' ones) and then create a new one for data storage.
(same disclaimer as above; this verbatim text was originally posted to NotebookReview's user forum on 19 November 2013)
I don't think cloning will work because of how the SATA controller is set up to use the disk plus an mSATA cache; switching to having mSATA accessible as an independent drive involves a BIOS change (at which point your spinning drive may not be readable anymore until it's wiped via formatting) as well as a driver change -- so even if you exported an image to another medium before making the BIOS change to make sure your content was available to be cloned onto the mSATA drive, the driver configuration from the image wouldn't be appropriate for the new mSATA-only config. I'll give you a somewhat higher-level step-by-step guide; if you need something incredibly granular, that would probably be more typing than most people would be willing to do, and at that point it may be worth getting help from a tech-savvy friend/collegue/family member. But here's what you'll need specific to this machine:
1. Buy a 256GB mSATA drive. I'd recommend the Samsung PM841 (not officially available for retail, but sold on Amazon through third parties), but the Crucial M500 would be a solid choice too and IS officially available for retail, so you'd benefit from firmware updates and such that way.
2. Grab the manual for your system at support.dell.com, which will contain instructions for removing the spinning drive (if you intend to do that) as well as swapping the mSATA unit.
3. While you're there, download the drivers you'll find there, though I would get the NVIDIA GPU drivers from NVIDIA and the Intel Wifi and Bluetooth drivers from Intel, personally.
4. Make sure you have a Windows 8.1 installer on a USB flash drive. You should be able to download the installer from Microsoft to create a suitable bootable flash drive.
5. Back up any data you want to keep from the magnetic drive, because it might not be readable anymore after the next step; I'm not sure, but it would avoid a hassle to have a backup.
6. Power up your machine and go into the BIOS. I don't have the machine yet so I can't tell you exactly what the name of the option is, but under a heading like SATA Mode (or something to do with SATA), switch it to AHCI; it will probably be on something that says RAID or Intel Smart Response prior to that. This will let you use the mSATA drive as an independent drive rather than treating it only as a cache. Then move the mSATA drive above the magnetic drive in the boot order.
7. Boot from the flash drive, install Windows onto the mSATA unit, and then install all required drivers and applications. If you want to use Intel Rapid Start, you'll need to take extra steps to partition your disk to support it. Intel's guide for this is here for MBR disks and here for UEFI. At that point if you retained the magnetic drive, you can format it to start clean and use it as bulk storage going forward, or you can leave it out to reduce weight, noise, and heat, as well as increasing battery life.