Performance Summary & Conclusion
Competitively, between the AMD and NVIDIA solutions we tested, the AMD Radeon HD 6990M CrossFire setup, in general offered better dual-GPU performance scaling, at least in the tests we ran. However, NVIDIA's and AMD's solutions traded victories, depending on the game engine we tested in. However, in single GPU performance, the NVIDIA GeForce GTX 580M showed itself to be faster more often than the AMD Radeon HD 6990M, taking the lead in all but one of our game tests (Metro 2033). Again, we'd offer that future driver updates can and probably will affect both single and GPU performance from both sides of the graphics equation.
The Alienware M18x is a notebook built for gaming and performance enthusiasts, plain and simple. This isn't a machine designed to strike a balance in power efficiency or portability by any means. Dell's Alienware division apparently built the M18x with one mission in mind--to deliver the best possible gaming and multimedia experience available in a self-contained, "desktop replacement" form-factor. To that end, Alienware has delivered masterfully.
Over the years, we've watched the Alienware M series of gaming notebooks evolve. Early on they were beefy, solidly built machines that still felt a little rough around the edges at times. However, the recent crop of Alienware M series machines, from the diminutive M11x to the midrange M14x and now the big Daddy M18x, offer refinement, build quality and performance improvements that easily deliver best-of-class experiences for enthusiasts in their respective categories and sizes. The only caveat is price.
Though our test systems came strapped with dual-GPUs, you can obviously configure an M18x at much lower price points versus the $2600 - $3300 range that we were playing at. A quick scan through Dell's M18x configuration menus shows we can build an M18x for about $2100 currently, with an NVIDIA GeForce GTX 560M, a 750GB 7200 RPM HD and 4GB of memory. Comparatively, you can find a 17-inch Asus G74-SX, with the same CPU and GPU but with 12GB of DDR3-1333 (M18x uses 1600MHz memory), a pair of 750GB drives in RAID 0, and a Blu-ray/SuperMulti combo drive -- all for about $1700. The trade-offs would be a smaller 17.3" LCD (not quite as high quality either) slightly less bling, along with more modest build quality/materials. In our opinion, you can't go wrong either way really.
That's a lot to digest, so we'll condense things down a bit. The long and short of it is this; the M18x is one heck of a gaming notebook and if only the best will do, this big fella is definitely plush and cranked up for performance. Though, if you're game for a higher-end dual-GPU build, you'll need to look hard at cost and feature options available.
Currently, a pair of GeForce GTX 560Ms is a $300 up-charge over a single configuration (not bad). A pair of Radeon HD 6990Ms in CrossFire is a $500 adder; also a reasonable premium if you consider how much faster they would be versus the 560 series from NVIDIA. On the other hand, if you're swinging for the fences, a pair of GeForce GTX 580Ms in SLI will cost you a whopping $1200 more. That is a huge price premium for what is currently a negligible if any performance boost versus AMD's CrossFire setup. We asked both Dell and NVIDIA about this discrepancy. Dell of course wouldn't take sides, saying pricing is what it is, so to speak. NVIDIA didn't have an official comment to offer.
We'll let you decide for yourself, which configuration you feel is right for you in the end. For now, one thing is very clear. The Alienware M18x is easily deserving of our Editor's Choice award.