RAM upgrade question.

I have an aging M17x that's starting to get a bit sluggish, I reformat it every six months or so to keep it clean but I think it's time to upgrade the RAM.
It currently has 4GB DDR2 SO-DIMM at 667MHz - 2 x 2048MB.
I'd like to upgrade to 2 x 4gb or 2 x 8gb but i'm not sure if that's possible with my motheboard.
So firstly, is it possible (specs below), what do you recommend and can I use DDR3?

Thanks in advance for any replies.

[1] Area-51® m17x
Display: 17" WideUXGA 1920 x 1200 LCD with Clearview Technology with Webcam
– Black
System Lighting: Alienware® AlienFX® System Lighting - Aqua
Operating System: Genuine Windows® Vista Ultimate - English
Notebook Tuners and Remotes: Mini Media Center Remote Control
Processor: Intel® Core™ 2 Extreme X9000 2.8GHz (6MB Cache 800MHz FSB)
Graphics Processor : Dual 512MB NVIDIA® GeForce® Go 8800M GTX – SLI Enabled
Memory: 4GB Dual Channel DDR2 SO-DIMM at 667MHz - 2 x 2048MB
System Drive: Dual Drive Configuration - 1.0 TB 5400 RPM SATA (2 x 500GB)
CD/DVD/RW: 8x Dual Layer Writer (DVD±RW, CD-RW) with LightScribe Technology
Turbo Cache Memory: None
Sound Hardware: Intel® High-Definition Audio (24-bit, 192Khz) with surround
sound
Keypad: Alienware® Customizable AlienFX® Keyboard with Numeric Pad - English

Wireless Network Card: Internal Intel® Wireless 4965 a/b/g/Draft-N Mini-Card

 

First, it is a wrong forum tab to ask this question
you should ask this question here:

Alienware Area-51/Aurora and Legacy Systems

But....

if you have ddr2 , you can't use ddr3

I think you should be ok with 2x4gb ddr2

2x8gb is NOT supported in your laptop

http://forum.notebookreview.com/alienware-area-51-aurora-legacy-systems/601419-area-51-m17x-ram.html

 

Thank you for your answer

 

I thought 8gb was the max in the M17-R1? Could be wrong