Performance Laptops vs. Performance Desktops

CPU wise you looking at 0.8Ghz less then the top desktop model, and a furture 1Ghz after overclock but higher turbo is going to make up some of that lose. That said performance is still great. Its in the region of deminishing return where performance don't increase that much. CPU is not the limiting factor.

GPU wise, not so great, 670m is same range of a low midrange graphic card. Not even 6850 performance level.

Also keep in mind a "gaming" laptop like the one you talking about it still very heavy, it is portable relative to a desktop but you don't want to carry it around with you all the time.

Laptop graphics cards are usually similar to a desktop model one or two steps below it. For example, a Geforce GTX 580M is a little weaker than the desktop GTX 560Ti. This obviously means that at the high end, desktops can just scale far beyond contemporary laptops.

And then there's overclocking, which can give a decent extra boost on desktops, but isn't really much of an option for laptops due to cooling concerns.

PS: Do keep in mind that gaming laptops are essentially just portable desktops, in the sense that they are bulky and their unplugged performance is limited.

A few comments/ideas:
1) You are living abroad! Get out of the house and experience the culture and learn the language! Don't waste your time in your room playing games! Believe it or not, but as a foreigner you will be a curiosity to the people around you and you will have tons of opportunity to make friends where you may not have been all that popular where you were from originally.

2) In many countries (especially European countries, but no place is immune) theft is a major issue, and you never want to purchase hardware that you cannot afford to replace. Along the same lines; Never store anything on a laptop that is not also backed up somewhere else as your data can walk away. This is where Lenovo laptops are handy; they are plenty fast, but as they look like they were made in 1980 nobody would steal it unless they knew exactly what it was, where as a flashy laptop will catch someone's eye and invite trouble. Sadly Lenovo does not make a gaming laptop though...

3) As far as performance goes. Dollar per dollar for gaming laptops are generally 2-7 years behind desktops. Even most of the current lineup of mobile GPUs are rebrands of the last generation, so be careful as to what you purchase.

4) Duel channel memory does not work in sets of 3. Get 2 or 4 dimms of ram (8 or 16GB). If they are claiming that 3 sticks works as duel channel then they do not deserve to be in business and are pulling your leg. Also, win7home will only do up to 16GB of ram, so do not purchase any more unless you also fork over the money fro win7pro (really 8GB is overkill for gaming and multi-tasking, I rarely use more than 5GB on my desktop unless doing massive video editing projects).

5) Sell the desktop and move exclusively to the laptop, and keep it on your person at all times. Flights are expensive (it costs me ~$1-2000 for my wife and I to go home, and that is just in the states) and will not make it conducive to fly home often. Especially if you get a part time job while you are away (or more likely a girlfriend), it becomes harder and harder to go back for long periods of time, and the desktop will just sit and rot, and the few times you do go home will mostly be spent sleeping and catching up with friends and family. Besides, then you can add to your laptop budget a bit, and not sit at home wondering if the thing is safe.

6) HDDs (especially 7200RPM drives) will eat power, produce heat, make noise, and for relatively little benefit for any gaming experience. RAID 0 will only fail on you and cause issues (especially as a daily driver and your only available PC), and RAID 1 will add some stability, but negate most of the performance gains that I think you are looking for. What I would suggest is to get a HDD, and pair it with an SSD. Have a 40-60GB partition dedicated to Windows and your most used programs, and then have a separate 60GB partition dedicated as a cache for the HDD, and use that to store all your music, videos, and less used programs. Set the HDD to sleep after 5 minutes to save on batter/heat/sound, and then the system will still fly with the SSD using much less power, 0 noise, and minimal heat. It will be MUCH faster than both HDDs in RAID1, and both faster and more stable than HDDs in RAID0.

7) "sound blaster compatable" simply means that it is a crappy realtek sound card with the Creative xFI MB2 software suite installed ($30 on amazon). It does help a lot over standard realtek, but it is only $30 special, not the same as having a dedicated Sound Blaster or Turtle Beach sound card. If it is a plain realtek chip without MB2 then go purchase it yourself, it helps a ton, and is relatively cheap.

8) While Silver may be a 10-15c step up from the stock compound, you are only talking a 2-5c difference between silver and diamond compound, so you really have to ask yourself if it is worth it.

8) If it were me here would be the changes I would make to the configuration:
-$80 Sandy Bridge CPU (IB's improvements are mostly on the iGPU... which you are not using, and games are not bottle-necked by CPUs these days. Plus the SB will OC better than the IB with less heat).
+$60 you want a blue ray reader/DVD writer (unless you are going to have your own TV there, in which case leave the stock drive in there).
+$15 clan install (or you can spend time uninstalling crap-ware yourself for free)
+$15 recovery DVDs (you still want to make your own image backup after you have your software setup the way you want, but keep these discs some place safe 'just in case')
+$15 Silver 5 compound
+$28 for 16GB of ram (oddly cheaper than going down to 8GB of 1333 and buying your own set of 8GB to make 16GB. But the point is that you do not want 12GB... that is just dumb to even have an option for)
Leave everything else stock

Build price $1553
SSD $245 256GB M4 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Total: $1798

Just move your image over to the SSD (or reinstall using the restore discs to the SSD), reformat the HDD and move your bulk files (music/movies/etc) over to it. This config will run faster than your config (worlds faster for program loads), quieter, longer battery, and all for less money  . And with an SSD that large you should not need to mess with SSD caching, or installing programs over multiple drives (though that is still an option if you choose a smaller SSD). You also do not need to worry about RAID which can be a bit annoying (meaning you loose EVERYTHING if one drive goes down), and add 5-20sec to your boot time (it takes time to initialize the RAID controller, which negates any time savings for boot time).

Thanks for your reply, that's quite an informative post. I wouldn't normally go above 8 GB of RAM anyway but I want 1600 MHz and the only 8 GB they have is 1333, so I chose 12 but I didn't know how dual channel memory works I guess... I'll keep in mind what you said.
But the thing is, I chose the Kingston CL9 and not the standard RAM they have on the list (the brand is not mentioned). I'm not sure if this is a smart move though. I thought I might want to overclock the RAM in the future and a good quality model might be better for this. Again, not sure how laptops would react in terms of heating if you overclock your RAM or if they even allow it...  

About RAID 0, I've been using it on my desktop since 2 years and it hasn't caused me trouble and I want to go for more space, so I'm not sure about SSDs. The model you mentioned actually looks very promising but I'm not too sure how comfortable I am about unscrewing a new laptop just yet...