Gpu confusion?

After 2 years of going to lans im kind of over hauling around my custom built rig so i decided to purchase a powerful laptop. I have several alienware models that I have in mind but I cannot really make up my mind. I was looking at both the m17x and m15x. Both of the models have the i7 620M but have different GPU's. The M17x has the 4807m xfire and the M15x has the 5850m. I tried looking up reviews for the 4870m xfire but they seem to be based off the old drivers which aparently is crap. From those results its hard to conclude the performance difference. So basically my question is that how much performance difference is there between the 5850 (which i will OC to hell and back, 775/1100) and the 4870m xfire in terms of gaming? My primary use will be gaming
Thanks Guys help much appreciated

 

A lot!
Comparing a single GPU setup to XF setup is not fair.
Saying that i favor single card setups myself but if you can afford it get the 5870 in XF.

 

As I understand it, there are less driver issues with a single GPU option,

But it really comes down to price, how much do you want to spend?

Either option (single 58xx or CF) is going to give you a decent perfromance rated laptop.

 

Crossfire setups are better for benchmarking but it comes with their own set of headaches and crappy driver support. Go with a single 5850/5870 and you'll save a lot of troubleshooting down the road.

 

what will you be doing with the laptop? if its extreme gaming go for 5870 xfire!!!! you'll appreciate the fps gain. Although i can pretty much max out any game on my 5850

 

@ Mandrake,
Very true.
Plus, there aren't too many games that will be unplayable @max settings with a single 5870.

 

My budget is under 2k... Cant really fit in the 5870 xfire lol >.> So you guys rekon it would be better with just the 5850?

 

I've never really seen any driver issues for any crossfire setup-excluding, ironically, the latest 5870 crossfire.

A single 5850 will be marginally faster than a single 4870. You're talking around 15%, maybe. Possibly less.

Add a second 4870...it all depends on the compatibility of the game but you could possibly see as much as 70% better performance, as compared to a single 5850, in the games that support Crossfire extremely well. Even those games that don't support Crossfire very well will most likely see more performance out of crossfire 4870s than a single 5850.

You'll appreciate the extra power from crossfire 4870s, particularly as more games come to support crossfire.

That's my take on it. Crossfire 4870s for sure. At the same time though, as the others say, there are very few games that the 5850 can't max out. Even those it can't max out will still look absolutely fantastic. Your choice, really.

If you want the most raw graphics power, then the M17x with crossfire 4870s is for you. If you don't want maximum power, then the M15x's benefits might be better for you, and it'll still max out many of the games you play, and still look great on those games you can't max.

 

Yea im not looking at maxing out games i just want to play them at high or highest at 30 frames or more.