Wmtl;

http://forum.techinferno.com/alienware-m15x/627-%5Bguide%5D-m15x-nvidia-470m.html#post7371

Guide - M15x with Nvidia GTX 470m 

IMPORTANT: The Nvidia 470m is not officially supported by Dell. Upgrading to this card may void your warranty.

Some background to this mod: The first guy who tried to put a Nvidia 470m in an Alienware M15x was @iloveb00bs in December 2010, shortly after the cardgot released.
Unfortunately it didn't work as desired, the card worked, but only at 2d clocks. All attempts to bring it to 3d clocks failed, and the card wasn't supported by Nibitor support at this time.

Also @widezu69 didn't get it to work a couple of weeks ago, so I didn't think it would be possible. But in the process of trying toupgrade the Asus G73JW of a colleague I got my hands on aNvidia GTX 470m and since we didn't get it to work in the G73, I thought let's try it again in the M15x... 
I had to mod the vbios to get it running at 3d clocks. I'm not that experienced with Nvidia cards, so that's probably why it took me a couple of attempts to get it working.

First I changed the 2d clocks and voltage (P3 in Nibitor) to 3d values. The result was that the card idled at 3dclocks, but as soon as I opened a 3d application it went downclocked itself to about 73MHz core and got to 2d voltage again... pretty annoying.
After some more tests I realized that I had to change the lower 3d clocks and voltage (P7 in Nibitor). This did the trick. Apparently the card only checks P7 and P3 in the VBIOS, the actual 3d clock entries (P15) seem to have no effect at all.

The fancontrol works perfectly. Haven't tested DP/HDMI audio yet, but I'll do this sometime soon.

Things to do before exchanging the card:
* Download the drivers. I used the latest Nvidia beta driver (v275.27) and the modded .inf files from laptopvideo2go. As the card comes from Clevo I guess the Clevo (and resellers) driver will work as well. But I usually prefer the latest driver for performance andstability.
* Also get GPU-Z for monitoring your video card and verifying it.
* Make sure you have thermal paste, maybe some new thermal pads as well as something to 
clean the heatsink (e.g. isoproply alcohol) and some cloths around. I also highly recommend using a grounded ESD-mat and a wristband.
* Know what you're doing. You need to partially disassemble your machine to get to theGPU. Prepare yourself thoroughly, check out my little GPU exchangement guide and if you need more information also the M15x service manual, as well as the official teardown video. It can be helpful to write down all the steps in advance when you're doing this for the first time.

In case there's still something unclear about the disassembling procedure after checking out all the stuff I justmentioned, just ask. Exchanging the GPU is really pretty easy.

* Very important: Make all the necessary preparations to flash the modified vbios to the card in order to get it working at 3d clocks:

You'll need a DOS bootable USB drive with NVflash on it. If you have already such an USB drive you can skip the next step and simply copy the mod470m.rom file from the attached archive to yourstick.

If you first need to create such an USB drive open an read the Spoiler:

Creating a bootable DOS USB drive (by @Brian K. )
Spoiler

The upgrading procedure:
1. Uninstall your GPU drivers.
2. Make a power drain (Turn off your M15x, remove the power cord and the battery. Then press and hold down the power button (Alienhead) for about 10-20 sec.
3. Remove your GPU - Here's alittle guide with pics in case you need some help.
4. Clean your heatsink, if necessary replace the thermal pads with new ones.
5. Make sure the 470m has a retention bracket on the back of the GPU. If not take the one from your old GPU and put it there.
6. Properly insert your GPU, make sure that it sits properly and that the die is clean. Apply the thermal paste, and attach the...