Hi John,
* SATA III is backwards compatible with SATA II, so no worries there.
* You will need to buy a bracket or make your own. Not all brackets will work due to how the drives mount in the 435MT. The bracket needs to have threaded holes in the bottom. This one looks like it will work:
http://www.amazon.com/SILVERSTONE-SDP08-3-5-2-5-Inch-Converter/dp/B002BH3Z8E/ref=pd_sim_pc_2
* If you plan on using your current 500GB HDD you will need a SATA data cable. The power cable should already be available on your PSU. The SATA data cable doesn't need to be very long, a 14" one will be fine. I suggest you get the kind that has locking connectors such as this one:
http://www.amazon.com/Monoprice-18-Inch-Locking-90-Degree-108783/dp/B009GUXU52/ref=pd_cp_pc_3
There are issues using SSD's in the 435MT relating to the lack of AHCI support in the BIOS. I am using an Intel 330 SSD which uses a SandForce controller. As a result of configuring my system as a single disk RAID setup the sleep mode doesn't work. Other than that it works fine. The Samsung 840 uses a Samsung controller so you may have different issues or no problems at all.
If the batteries on the motherboard are more than 2 years old then replace them. The 435MT mobo takes 2 each CR2032 coin cells. Install + side up.
Now for the tricky part-
Before you do anything backup the data on your current drive. By enabling RAID in the BIOS you will not be able to boot from your existing HDD since it was configured with the BIOS in IDE mode. You can still use it as a second drive but will need to reformat it which will erase everything on it.
When you run a single disk RAID setup you will need to be very careful. Never use Ctrl + I, that's uppercase i. If you do your system will try to build a RAID array which will not work and you will have to reload your OS all over again. You will also need to be careful when you eject any external drives using "Safely Remove Hardware" in Windows. With the BIOS set to RAID, all of your drives are available to eject. So be careful which drive you select.
There are also issues regarding doing a clean install of Windows 7. You didn't specify if you have upgrade media or a full install media. If it's a full install media then you can do a clean install no problem. If it is an upgrade media then you will have to jump through a few hoops. I suggest you read the articles on Paul Thurrott's Supersite for Windows:
http://winsupersite.com/article/windows-7/clean-install-windows-7-with-upgrade-media-128512
Step 1
Download the applicable drivers for your system from the Dell website. (The Dell Downloads website for the XPS-435MT doesn't have much there.)
For the most part, Win 7 will use up to date drivers for the 435MT.
You should be able to download the following from Intel's website:
* Intel Chipset INF Update Utility
* Intel Storage - Intel Matrix Storage Manager (driver to run the system in RAID)
The 435MT uses the Intel X58 Express Chipset and the Intel ICH10 Controller Hub
.
Copy the relevant drivers etc to a USB stick or burn to optical media.
Step 2
Backup your data on your existing drive if you haven't already.
Place the install media in the optical drive then shutdown the computer.
Remove all cabling from the back of the computer.
Step 3
Before opening the case, press and hold the power button for 30 seconds to bleed the capacitors.
Open the case. Ground yourself to the metal chassis inside the case. Do this frequently as you work to avoid static discharge.
Remove the current drive or disconnect both the data and power cables. You don't want to accidentally build a RAID array by having more than one drive connected. Also, you will be able to reinstall your current drive (as IDE) and boot from it if you have problems with your Samsung SSD or have problems installing and activating the OS.
Install the CMOS batteries on the motherboard. (2 ea CR2032, + side up)
Install the Samsung SSD and connect it to SATA-0.
Step 4
Make connections to the back of the case for power, monitor, keyboard, mouse, and Internet.
Power up the computer. When the Dell Logo appears hit F2.
In BIOS Setup, navigate to "Advanced Chipset Features". Change the SATA Mode to RAID. (IDE by default)
Navigate to "Boot Device Configuration". Select the First Boot Device to be whatever you use for your OS install media. (CD/DVD for optical media)
Save and exit BIOS Setup. Allow the computer to boot from the install media. Select Custom Install. At this point you can create partitions on your SSD if you want to but I would suggest you leave it as one partition. Follow the prompts to install the OS. After entering the Product Key select "Important Updates Only".
Step 5
After the system auto reboots when OS installation is complete it would be a good idea to make sure Windows 7 is activated before proceeding. If not, you may be able to get it to activate simply by installing Win 7 for a second time. You will also need to change the boot order again in the BIOS settings. Select the Samsung SSD as the First Boot Device.
Step 6
Run Windows Update several times to completely install all important updates. It will take a very long time. Reboot the computer.
Step 7
In most cases Win 7 will use the most up to date drivers.
Install the system drivers in the following order:
1) Chipset - I suggest you use the Intel Chipset INF Update Utility available from the Intel website.
2) Intel Storage - Intel Matrix Storage Manager
3) Audio
4) Video
5) Network Interface Card (NIC)
6) Bluetooth - CAB200 (Don't install the icon mgr, it only messes things up)
7) Mice and Keyboards if necessary.
Step 8
Confirm TRIM is enabled in Win 7
Start> All Programs> Accessories> Right click Command Prompt, select "Run as Administrator"
At the command prompt type:
fsutil behavior query DisableDeleteNotify
Press the Enter key. Two results are possible:
DisableDeleteNotify = 0: This indicates that TRIM is enabled and working on the operating system.
DisableDeleteNotify = 1: This means that TRIM is not enabled
By default Win 7 will disable disk defragmentation, Superfetch, ReadyBoost, and prefetch on SSD's but it doesn't hurt to confirm.
See this:
http://blogs.msdn.com/b/e7/archive/2009/05/05/support-and-q-a-for-solid-state-drives-and.aspx
Step 9
Make sure Win 7 is running okay and your hardware works before you install your original 500GB HDD as a second drive and reformat it.
One other thing,
The original PSU that came with the 435MT is marginal at best. Over time it degrades to a point where it doesn't supply enough power to boot. This will be evident when the system won't start and the power button flickers amber. The green LED on the back of the PSU will still be lit, however it won't supply enough power to boot. So if you haven't replaced the PSU yet keep that in mind.
Good Luck!