The Alienware M18x Revisited

In our first run with the Alienware M18x, we sat down and took a look at the notebook itself along with NVIDIA's current top shelf mobile graphics part, the GeForce GTX 580M. We came away from the experience with mixed impressions of the M18x itself, a notebook that is by all means incredibly powerful but also seems to lose a lot of the balance that made the M17x R3 so desirable. On the other hand, the GeForce GTX 580M wound up being the fastest mobile GPU we'd yet tested, made only more formidable through the SLI configuration the M18x enables.

Today, Alienware has graciously provided us with the second half of the current top shelf performance equation in the form of a near-identically configured M18x, this time with two AMD Radeon HD 6990Ms in CrossFire. We'll also take a look at the Intel Core i7-2920XM's stock performance and compare it against the overclocked settings Alienware allows you to configure it with.

In a beautiful bit of synchronicity, our Radeon-equipped M18x also uses Alienware's black shell instead of the "nebula red" they equipped our GeForce model with. Other than that, this review unit is going to seem very familiar to those of you who caught the first part of our review. If you missed it, give it a read first.

There are a couple of major differences between this unit and our last one that are worth pointing out. First, while our GeForce-based system simply had a pair of 750GB 7200-RPM hard drives, this one has them configured in the RAID 0 that Alienware inexplicably seems to love shipping notebooks with. Don't ask me why, I just work here, but hopefully if I keep harping about this eventually they'll offer an SSD+HDD configuration in models that support it--the way they should have been doing for a while now. This is liable to affect PCMark scores somewhat.

The other major difference? The Radeons of course! While the AMD Radeon HD 6970M sported a slightly cut down Blackcomb GPU, essentially a downclocked version of the desktop Radeon HD 6850, the 6990M features a Blackcomb with all 1120 shaders enabled and a minor clock speed bump beyond the 6970M. Compared to the jump from the GeForce GTX 485M to the 580M, this is a bit more substantial of an improvement in raw hardware power. The 6990M features those 1120 shaders and a core clock of 715MHz (up from 680MHz on the 6970M, but down from the 900MHz of the desktop 6870), with 2GB of GDDR5 strapped to a 256-bit memory bus and running at an effective 3.6GHz (down from the desktop model's 4.2GHz clock.)

Since this M18x is otherwise identical to our previous system, we've eschewed retesting the screen and battery life, and our assessments of the unit's design and build quality from the previous chapter still apply. While the two differ in graphics configuration, Alienware uses muxes to switch the graphics hardware on and off, making any differences in running time academic at best. We've also opted to run our CPU-based benchmarks (and the 3DMarks) again using the i7-2920XM at stock speeds to compare performance against the maximum preset overclock Alienware makes available. The net result is a tremendous amount of new data for us to sift through.

Application and Futuremark Performance

In the first part of our Alienware M18x review, I pointed out that the overclock on the Intel Core i7-2920XM processor is actually higher than the stock clocks of the desktop i7-2600K. More than that, our dual-GPU configurations should be in the neighborhood of a pair of desktop GTX 560s and certainly within striking distance of most single-GPU desktop gaming systems. So to up the ante and spice things up a bit, where possible I've included the results from CyberPower's Gamer Xtreme 4000, a desktop system I reviewed at the beginning of the year that features an overclocked i7-2600K (at 4.4GHz) and a GeForce GTX 570.

Additionally, for the application and Futuremark testing, I've also included results from the M18x with the i7-2920XM at stock clocks and a single HD 6990M. Keep in mind that in some cases, the RAID 0 in the Radeon-equipped M18x might give it a slight edge.

In most cases, the AMD and NVIDIA-based M18x notebooks mirror each other and trade blows. As far as PCMark 7 is concerned, the difference between the two is negligible, and not only that, it doesn't seem heavily impacted by the RAID 0. Meanwhile, the ASUS G74, Clevo, and HP notebooks benefit from SSDs to boost their scores.

As far as Cinebench is concerned, the two graphics solutions have roughly the same CPU overhead, and multi-GPU configurations don't seem to affect it. The numbers are close enough to call it a wash. The x264 benchmark yields the same results. Meanwhile, our overclock on the i7-2920XM has a tangible performance improvement but ends up being surprisingly minor compared to the massive lead the overclocked desktop i7-2600K stakes.

In the 3DMarks, the Radeon and GeForce solutions basically trade blows with no serious leads going to either contender. At least as far as Futuremark is concerned, AMD and NVIDIA's top-end parts are basically comparable.

Gaming Performance

We've seen that as far as Futuremark is concerned, the AMD Radeon HD 6990M and NVIDIA GeForce GTX 580M are essentially comparable. 3DMark doesn't tell the whole story, though, and we've seen graphics hardware perform well in it and then go belly up in actual benchmarking situations. Maybe our game testing will break the stalemate?

At least in our "high" preset, the two tend to trade blows, though when the GTX 580M wins it wins big, blowing past the Radeon in STALKER, Mafia II, and surprisingly DiRT 2, where the Radeon puts in an unusually poor performance. The 6990M is still totally playable in every case, but the GeForce is always at least on par with it.

The gap closes a bit in our "ultra" testing suite, but still generally favors the GeForce in multi-GPU settings while the single GPU solutions perform roughly on par with each other. Meanwhile, our multi-GPU solutions are oftentimes faster than our gaming desktop, and that's not too shabby. For users that want a desktop-level gaming experience in a notebook and are willing to pay for it, SLI and CrossFire look ready and able to provide it.

Heat and Noise

Given the relatively similar configurations of the two M18x units we've reviewed, it should come as no surprise that thermals are remarkably close between them as well. For reference we're including the results from the NVIDIA GeForce GTX 580M-equipped system to compare against the pair of Radeons in this unit, though it bears mentioning that HWMonitor could only read the temperatures from one Radeon HD 6990M. The RAID 0 configuration also prevents HWMonitor from getting temperature readings from the hard drives.

Single Radeon HD 6990M (Left) and CrossFire (Right)

Single GTX 580M (Left) and SLI (Right)

So what can we gather from this information? First, it seems that the pair of GeForces run ever so slightly hotter than the Radeons, and that produces warmer peak core temperatures on the overclocked i7-2920XM. While the GeForces are really pushing the i7-2920XM to its thermal limits, the Radeons still get peak temperatures above 90C on the cores, more than anyone wants to see.

On the plus side, the i7-2920XM's overclock doesn't seem to be exacting too much in the way of heat. At stock speeds thermals are essentially comparable under load when only a single GPU is enabled. End users of the M18x may want to keep an eye on temperatures just to be on the safe side, but should still be reasonably comfortable with a solid overclock on their processor.

As for noise, the fans run too low to really be noticeable when the M18x is idling, but under load it picks up to about 43dB. This is still nowhere near as nightmarishly loud as the Clevo X7200 can get; that notebook has to cool roughly 330 watts of hardware in a chassis roughly the same size as the M18x. Overall the M18x is definitely noticeable when being stressed, but it's not overwhelmingly so.

Conclusion: NVIDIA Retains Their Title, But Barely

We had a hunch that NVIDIA's GeForce GTX 580M would continue to be the fastest single GPU available in notebooks, and that turned out to be accurate...mostly. In a couple of games the 580M is a slam dunk, while in others it trades blows with AMD's Radeon HD 6990M. Once multi-GPU solutions are brought into the equation, things tend to veer more in favor of NVIDIA's solution, but we remind you that two isn't always better than one: it may look better on charts, but benchmarks don't tell the stories of micro-stuttering and sometimes inconsistent performance. There's a reason none of our editors would recommend a multi-GPU solution in a desktop, and so I personally can't really recommend it in a notebook either.

What are we left with? Well, once again my recommendation at the end of the first part of the M18x review applies: the M18x feels like too much, especially compared to the M17x R3. That's doubly true when you realize the M18x's only single-GPU solution is a GTX 560M; everything else is SLI or CrossFire. So when you bounce down to the M17x R3, you can get a single 6870M, GTX 560M, 6990M, or GTX 580M, and unfortunately for NVIDIA, this is where AMD steals the show.

Simply put, the 580M just isn't worth the $300 premium over the 6990M. The two are comparable enough that situations where NVIDIA's part leads just don't justify the massive difference in price. Those of you still itching to configure an M18x will have an even easier time with it: a pair of GTX 580Ms is a staggering $700 more than a pair of 6990Ms. If price is of no consequence to you then by all means go for NVIDIA's solution, but if it matters even in the slightest, AMD wins the value competition hands down. Think it's just Alienware? A visit over to AVADirect reveals the same kind of price difference in a custom configured X7200.

Ultimately both of these solutions are more than adequate for getting your mobile game on, but AMD really does win the value proposition by a landslide. The GTX 580M is a fantastic GPU and I've certainly gotten a lot of mileage out of mine, but I also need the support for CUDA. If you don't, your answer is a simple one, and the M17x R3 with a Radeon HD 6990M may just wind up being the best balance of price and performance for mobile gamers. The M18x remains, as before, too much for most users.