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Dell Alienware X51, SFF PC Gaming Refined
Date: Feb 01, 2012
Author: Dave Altavilla
Introduction and Specifications
Dell's enthusiast gaming PC division has built a legacy on designing over-the-top desktops and notebooks, that push the boundaries of performance and style with an unmistakable design flair.  We've been pretty impressed with the Alienware systems we've looked at thus far, and though they tend to run a premium in terms of price, performance and design quality generally scale along with that higher price tag.

On the test track, Alienware notebooks have racked up some of the best performance numbers we've seen and the company's desktops rank right up there as well.  One shape the Aliens have never assumed previously, however, is the small form-factor desktop.  And let's be honest, systems in this weight class generally aren't known for their gaming prowess but usually serve as home theater or mainstream PCs.  The folks at Alienware have a different sort of vision for their next alien life form and if you weren't paying attention, you'd almost mistake it for a game console rather than a PC. But you're here at HH, so you're obviously paying attention. And so are we.

You could say the Alienware X51 gaming PC system got our attention when it hacked into our news channel not long ago.  So we decided to send a peaceful return transmission and allow it to touch down on a test pod in our lab.

But first, we interrupt this program to allow the Aliens a bit of air time in this hands-on demo. Then get set for the specifics, the benchmarks and our analysis.

Alienware X51 Small Form Factor Gaming PC
Specifications & Features
Operating System:
Ethernet LAN/Wireless:
Front Panel Ports:
Rear Panel Ports:
Power Supply:

Core i5-2320 - 3GHz, 6MB Cache with Turbo Boost 2.0
8GB Dual Channel DDR-1333
NVIDIA GeForce GTX 555
Western Digital 1TB, 7200RPM, 32MB Cache, 6Gbps SATA
Slot-Loading Dual Layer DVD Burner (DVD±RW,CD-RW)
Windows 7 Home Premium X64
10/100/1000 Ethernet, DW1502 Wireless-N WLAN Half Mini-Card
2 x USB 2.0; Headphone and Mic
4 x USB 2.0; 2x USB 3.0; GbE LAN; Optical SPDIF; Audio inputs, HDMI
Integrated 7.1 surround sound
330 Watt External AC Adapter
1 Year Limited
$999 (as configured and tested)
Front-Height: 13.504"  (343mm)
Rear-Height: 12.54" (318.5mm)
Depth: 12.52" (318mm)
Width: 3.74" (95mm)
Starting Weight: 12.1 lbs (5.49 Kg)

The Alienware team played it smart configuring the X51.  If you're a gamer, you need a fair bit of CPU horsepower and clock speed to drive data requests to the primary graphics engine that ultimately works the magic of rendering shaders and pushing pixels to the screen. However, you darn sure better have a decent GPU at the ready, so Alienware's choice of NVIDIA's GeForce GTX 555 was spot-on.  The GeForce GTX 555 is a 288 CUDA core machine and while you may be lulled into thinking it's a midrange workhorse, it's actually no slouch, as you'll see in the benchmarks that follow.  Also, backing Intel's quad-core Core i5 CPU is 8GB of DDR3-1333 system memory and a fairly peppy 7200RPM 1TB WD hard drive.

Again however, the X51's component selection is a bit deceiving and perhaps underwhelming at first glance, so let's get a closer look at the hardware and go under the hood.

X51 Design and Features
In terms of its exterior design and aesthetics, the X51 definitely borrows more than a few cues from popular current game console designs. Whether you consider the X51 in light of the Xbox 360 or PS3, it's easy to see that the Dell Alienware design team intended this machine to drop right into the same footprint with very similar living room appeal.  And the similarities don't stop at just the skins.

Alienware's AlienFX custom lighting adorns the side panels of this toaster-sized machine. These panels can assume a myriad of hues that you can select in the AlienFX Command Center control software that comes pre-loaded on the machine. Alienware was also smart to keep the glossy trimmings down to a minimum, with only the front face of the system sporting a signature angular midnight black grill.  With a pair of USB 2.0 ports, headphone and microphone jacks and a slot-load combo DVD/CD RW drive up front, the X51 is somewhat understated for an Alienware rig, though its glowing alien head logo tips you about what's inside this little beast.  The front logo is also customizable in terms of lighting effects, like the side panels are, via the AlienFX software.  One notable missing feature we would have liked to see carved into the front panel would be an SD card slot, though you could just hang one off a USB port of course.

The back side of the X51 system sports a surprising array of ports and features; pretty much anything you'd want to connect this system to in a desktop environment or perhaps in the entertainment center, just to piss off that aging Xbox 360 a little bit.  The HDMI port off the integrated graphics of Intel's Sandy Bridge Core i5 processor is there, though if you're up for some big screen gaming, you're better off using the mini-HDMI connector on the NVIDIA GeForce GTX 555 graphics card, which by the way is a full dual-slot affair that exhausts outside the X51's classy little chassis.

From there you also get copious amounts of USB connectivity, with four USB 2.0 ports and two USB 3.0 SuperSpeed ports offering a 5Gbps signaling rate connection for up to 10x the performance when connected to a USB 3.0 compatible device.  There are also integrated 7.1 surround sound ports, driven by Realtek integrated HD audio, as well as optical SPDIF and coaxial SPDIF ports.  Finally, integrated Gigabit Ethernet connectivity (one port) comes via a Realtek PCIe Gigabit Ethernet controller.

The external AC adapter PSU for the X51 that we received is a massive 330 Watt brick, though a 240 Watt PSU is standard.  We'd suggest going with the upgraded 330 Watt brick you see here, for the extra headroom, should you wish to upgrade a bit down the road.  Speaking of which, let's give you a look at some X51 alien guts.

Internal Tear Down and Components
Looking at the size of the Alienware X51, you'd think the company had to resort to notebook components to get the job done in such tight quarters.  However, the X51 is a case study in mechanical design engineering, when it comes to layout, thermal performance and acoustics.

Dual slot graphics - NVIDIA GeForce GTX 555 with a spare PCIe Power connector available

We expected to see a single slot graphics card in this machine but Alienware managed to stuff a dual-slot cooler graphics card design right on top of the 3.5-inch hard drive.  The card plugs into a single PCIe X16 slot on the motherboard via a riser card adapter and there are no other available slots for expansion. The squirrel cage style fan design in this card pushes warm air out the back plate of the card, so it doesn't end up warming the interior. Also, surprisingly, this GeForce GTX 555 only ramped up to about 76ºC under full load when testing and was only mildly audible at that point.   In fact, when idling, the system can barely be heard.  You literally have to lean your ear up to it, unless the room you're in is very quiet.  Under heavy duty gaming, the system isn't much noisier than your average game console actually, which is pretty darn quiet, considering how much more raw compute horsepower the X51 has.

Speaking of which, if you wanted to ramp your gaming performance up even more in the future, there is a spare 6-pin PCIe power connector available inside the X51, though you've only got another 100-115 Watts or so to play with, in terms of power budget, so long as you chose Alienware's 330 Watt PSU option.  Since the X51 sports a cool, calm and collected Intel Core i5-2320 quad-core CPU, only a half-height CPU cooler is required.  Its fan pulls warm air off the heatsink and up through the fan shroud (top left shot) and then out the back of the chassis.

You can also see WD's rather snappy 1 Terabyte Caviar Blue drive here.  This is a 7200RPM, 32MB cache, 6Gbps SATA hard drive that puts up some respectable numbers as you'll see on the benchmark pages ahead. Also visible are a pair of DDR3 DIMM sockets, populated with a pair of 4GB DDR3-1333 sticks, sans heat spreaders.  The X51 doesn't push the envelope of DDR3 clock speeds so heatspreaders are simply not needed.  Not to mention memory bandwidth is not an issue for this system, as you'll note in our test numbers as well.  If you look closely, just behind the silver heat sink, you can see the 802.11n WiFi radio nestled in a mezzanine style card socket.  Finally, about the only component in the system, besides the mini-ITX motherboard, that is actually a small form factor product, would be the slim DVD/CD RW combo drive the rides just above the ATX power connector on the motherboard.  This is a slot load optical drive that accepts media in through a thin slot on the front side of the X51.

Enough of the geek grope and ogling.  What do you say we put it all back together, run some numbers and game it up?

Test Setup and SANDRA
Test System Configuration Notes: All of the test systems in this article were factory-built machines that we tested exactly as they were setup from the factory, with a few small exceptions.  We ensured that Windows 7 power plans were set to high performance and that system sleep or hibernate settings were turned off, as well as screen savers. Also, systems allowed to pull down any/all Windows updates for the hardware and software enabled on the machines.  From there, we installed all benchmark and game software and then hard drives were defragmented. The systems were then rebooted and we commenced with all testing.

**Note:  We'll point out that the reference numbers we're comparing the Alienware X51's performance to were taken from full-sized multimedia and gaming desktop systems. Other than the X51, the rest of our test systems are full- or mid-ATX towers.

HotHardware's Test Systems
Specifications & Features
Alienware X51:
Core i5-2320 3GHz
8GB Dual Channel DDR3-1333
1GB NVIDIA GeForce GTX 555
1TB  WD 7200RPM HD 6Gbps
330 Watt PSU
Windows 7 Home Premium 64Bit
Dell XPS 8300:
Core i7-2600 3.4GHz
8GB Dual Channel DDR3-1333
1GB AMD Radeon HD 6770
2TB Seagate 7200 RPM HD 6Gbps
460W PSU
Windows 7 Home Premium 64Bit
iBuyPower BTS11:
Core i5-2500K 3.3GHz
8GB Dual Channel DDR3-1333
1GB NVIDIA GeForce GTX 550 Ti
750GB WD 7200 RPM HD 6Gbps
700W PSU
Windows 7 Home Premium 64Bit
HP Pavilion Elite H8 1050:
Core i7-2600 3.4GHz
10GB DDR3-1333
1GB AMD Radeon HD 6850
1.5TB WD 5400RPM HD 3Gbps
460W PSU
Windows 7 Home Premium 64Bit
SiSoftware SANDRA{Title}
Synthetic Preliminary Measurements
We began our testing with SiSoftware's SANDRA 2011, the System ANalyzer, Diagnostic and Reporting Assistant. We ran four of the built-in subsystem tests that partially comprise the SANDRA 2012 suite with our test systems (CPU Arithmetic, Multimedia, Cache and Memory, and Memory Bandwidth). All of the scores reported below were taken with their processors running at its default settings, with Turbo enabled, and with 8GB of RAM running in dual-channel at 1333MHz.

In terms of raw general compute power, the Core i5-2320 quad core CPU in the Alienware X51 is no match for the Core i7 quad-core processors in the HP and Dell XPS systems.  Furthermore it doesn't keep pace with the higher clock speed of the 3.3GHz Core i5-2500K in the iBuyPower system either.  However, again, the X51 is built as a gaming system first, so we'll see if this translates to a noticeable deficit beyond these pure synthetic measurements that don't take into account other subsystem performance in the X51.

In terms of storage subsystem bandwidth and memory bandwidth, the Alienware X51 keeps pace with these full-sized machines. The Physical Disk benchmark rates the WD Caviar Blue drive in the X51 at about 105MB/sec on average, just a hair behind the WD 750GB and 2TB Seagate drives found in the iBuyPower and Dell XPS systems.  Memory Bandwidth is rated at 17.5GB/s for the X51, right in line with the other 8GB installations but just ahead of the 10GB setup in the HP Pavilion H8.

PCMark Vantage and PCMark 7
Next. we put these four systems through their paces with PCMark Vantage and Futuremark's latest PCMark 7 benchmarks.  These are general performance test suites that measure performance metrics across a wide range of workloads and usage models.

PCMark Vantage
General Application and Multimedia Performance
This synthetic benchmark suite simulates a range of real-world scenarios and workloads, stressing various subsystem in the process. Everything you'd want to do with your PC -- watching HD movies, music compression, image editing, gaming, and so forth -- is represented here, and most of the tests are multi-threaded, making this a good indicator of all-around performance.

We should note that the PCMark test suite results, in general, are heavily affected by both storage subsystem and processor throughput.  Here the X51 trails even the slowest full-sized machine, though by a negligible variance.  Graphics performance is hardly stressed in this test, with only DX9 rendering required to complete the test.

PCMark 7
General Application and Multimedia Performance
Futuremark's PCMark 7 is the latest version of the PCMark whole-system benchmarking suite and  combines more than 25 individual workloads covering storage, computation, image and video manipulation, Web browsing, and gaming. It's specifically designed to cover the full range of PC hardware, from netbooks and tablets, to notebooks and desktops.

Here the Alienware X51 fared about as well as it did in the earlier Vantage version of PCMark.  Not a surprise really.  Let's look at a few metrics that will set overall system and gaming performance apart a bit more.

Cinebench and 3DMark 11
Cinebench R11.5 is an OpenGL 3D rendering performance test based on Cinema 4D from Maxon. Cinema 4D is a 3D rendering and animation tool suite used by 3D animation houses and producers like Sony Animation and many others. It's very demanding of system processor resources and is an excellent gauge of pure computational throughput.

Cinebench R11.5
Software Rendering Performance - CPU
This is a multi-threaded, multi-processor aware benchmark that renders and animates 3D scenes and tracks the length of the entire process. The rate at which each test system was able to render the entire scene is represented in the graph below.

Here again, the Alienware X51 puts up similar results to what we saw in the SANDRA CPU and Multimedia tests.  The lower speed Core i5-2320 CPU in the X51 just doesn't offer as much available CPU horsepower as these other full-sized systems with Core i7 quad-cores and the higher-end Core i5-2500.  That said, the Alienware X51 is a gaming system first and foremost, so let's see if it has enough CPU juice to hang with the big boys but the right amount of GPU muscle to perhaps even show them up.

3DMark 11 Benchmarks
Synthetic DX11 Performance Tests

Futuremark 3DMark11

The latest version of Futuremark's synthetic 3D gaming benchmark, 3DMark11, is specifically bound to Windows Vista and WIndows 7-based systems due to its DirectX 11 requirement, which isn't available on previous versions of Windows. 3DMark11 isn't simply a port of 3DMark Vantage to DirectX 11, though. With this latest version of the benchmark, Futuremark has incorporated four new graphics tests, a physics tests, and a new combined test. We tested the graphics cards here with 3DMark11's Extreme preset option, which uses a resolution of 1920x1080 with 4x anti-aliasing and 16x anisotropic filtering.

In 3DMark 11 the tables turn a bit.  Here the Alienware X51 surges past the Dell XPS and iBuyPower systems by a sizable margin and just falls short of catching the Radeon HD 6850-infused HP system.  Let's see if these synthetic benchmark scores translate into real world gaming performance results.

Metro 2033 and STALKER Benchmarks
First up for in-game performance testing, we have Metro 2033 and S.T.A.L.K.E.R., both of which are absolute murder on graphics cards in terms of workload but also boast impressive cutting-edge visuals.

Metro 2033
DX11 Gaming Performance

Metro 2033

Metro 2033 is your basic post-apocalyptic first person shooter game with a few rather unconventional twists. Unlike most FPS titles, there is no health meter to measure your level of ailment, but rather you’re left to deal with life, or lack there-of more akin to the real world with blood spatter on your visor and your heart rate and respiration level as indicators. The game is loosely based on a novel by Russian Author Dmitry Glukhovsky. Metro 2003 boasts some of the best 3D visuals on the PC platform currently including a DX11 rendering mode that makes use of advanced depth of field effects and character model tessellation for increased realism.

First, in the immortal word of Ricky Ricardo, we have a little bit of "splaining to do."  As you'll notice we only have numbers from the X51 for our 1080p resolution. For the other full sized systems we didn't have the reference numbers on hand at 1080p but you can certainly garner a view of performance based on the other two resolutions.  Here the Alienware X51 stacks up much like it did in the 3DMark 11 test, besting two of the full-sized gaming systems but not quite catching the Radeon HD 6850 power HP rig.

S.T.A.L.K.E.R. - Call of Pripyat
DX11 Gaming Performance


Call of Pripyat is the third game in the S.T.A.L.K.E.R. series and throws in DX11 to the mix. This benchmark is based on one of the locations found within the latest game. Testing includes four stages and utilizes various weather conditions, as well as different time of day settings. It offers a number of presets and options, including multiple versions of DirectX, resolutions, antialiasing, etc. SunShafts represents the most graphically challenging stage available. We conducted our testing with DX11 enabled, multiple resolutions, and Ultra settings.

STALKER shows a different result with the Alienware X51 taking the lead position at all resolutions.  This test is a little less demanding versus Metro 2033's gauntlet but its interesting to see the GeForce GTX 555 in the tiny X51 actually powers it past the other full-sized systems.

Lost Planet 2 and Far Cry 2 Benchmarks
FarCry 2 is an aging game title but it's DX10 powered engine still renders gorgeous visuals.  Here we cranked up AA to 8X levels just to clean up pixels a bit more and put a strain on our test systems.

FarCry 2
DX10 Gaming Performance

FarCry 2

Like the original, FarCry 2 is one of the more visually impressive games to be released on the PC to date. Courtesy of the Dunia game engine developed by Ubisoft, FarCry 2's game-play is enhanced by advanced environment physics, destructible terrain, high resolution textures, complex shaders, realistic dynamic lighting, and motion-captured animations. We benchmarked the graphics cards in this article with a fully patched version of FarCry 2, using one of the built-in demo runs recorded in the Ranch Map. The test results shown here were run at various resolutions and settings.

Here it's game, set and match for the Alienware X51 machine and this the alien nation took the top spot by a more comfortable margin.  Even at 1920X1080 resolution with 8X AA enabled the X51 maintains solid performance well in excess of playable frame rates.

Lost Planet 2
DX11 Gaming Performance

Lost Planet 2

A follow-up to Capcom’s Lost Planet : Extreme Condition, Lost Planet 2 is a third person shooter that takes place again on E.D.N. III ten years after the story line of the first title. We ran the game’s DX11 mode which makes heavy use of DX11 Tessellation and Displacement mapping and soft shadows. There are also areas of the game that make use of DX11 DirectCompute for things like wave simulation in areas with water. This is one game engine that looks significantly different in DX11 mode when you compare certain environmental elements and character rendering in its DX9 mode versus DX11. We used the Test B option built into the benchmark tool and with all graphics options set to their High Quality values.

It's no secret that Lost Planet 2 always seems to favor NVIDIA GPU driven systems and as a result, the X51 once again beats out these full-sized desktop PCs by a comfortable margin.  We had our pixel processing set at 4X AA levels but if you backed things down to 2X perhaps, you'd likely see playable frame rates even at 1080p resolution.

Batman Arkham City and Power Consumption
Though we didn't have reference numbers to compare it to, we figured it made sense to run the Alienware X51 over various resolutions and settings with Batman Arkham City.  We even turned on NVIDIA PhysX in the game engine, to ramp up the visuals and work the little alien speedster a bit harder.

Batman Arkham City
Cutting Edge DX11 Game Play with Enhanced Physics Effects

Batman: Arkham City

Batman: Arkham City is a sequel to 2009’s Game of the Year winning Batman: Arkham Asylum. This recently released sequel, however, lives up to and even surpasses the original. The story takes place 18 months after the original game. Quincy Sharp, the onetime administrator of Arkham Asylum, has become mayor and convinced Gotham to create "Arkham City" by walling off the worst, most crime-ridden areas of the city and turning the area into a giant open-air prison. The game has DirectX 9 and 11 rendering paths, with support for tessellation, multi-view soft shadows, and ambient occlusion. We tested in DX11 mode with all in-game graphical options set to their maximum values, at various resolutions.

Though we had image quality set to very high, tessellation and PhysX turned on and FXAA enabled in the game engine, the Alienware X51 still maintain playable frame rates, right on up through 1920X1080 resolutions.  With this system, you can quite literally play any game on the market currently, at high resolutions and high image quality settings.

Power Consumption
Idle and Full Load Power Draw
Before bringing this article to a close, we'll take a look at power consumption of the Alienware X51 versus the other full sized systems we tested. We let each system boot and sit idle before measuring idle power and then loaded down each system with both an instance of Prime95 (to load down the CPU) and Furmark (to load the GPU) before taking our full load power consumption measurements.  Our goal was to give you an idea as to how much power each configuration used while idling on the desktop and while under a heavy workload. Keep in mind, this is total system power consumption being measured at the outlet.

Loaded for bear with Prime95 and Furmark, only pushing 212 Watts

Another impressive turnout for Alienware's X51, as the little system consumes the least amount of juice either at idle or under full load.  Its PSU has a significantly lower power capacity as well but the external brick is likely more efficient that the larger standard internal PSUs in the full sized systems.  When you consider it's performance, the X51 has the best performance-per-watt profile of the bunch, easily.

Performance Summary and Conclusion
Performance Summary: When some consider the size of a small form factor system, they tend to set their expectations in performance directly proportional to that size, for the most part.  To say we were impressed with the numbers this little machine put out would be an understatement.  We'll stop just short of "blown-away" but we're a bit jaded around these parts anyway.  In terms of general compute performance, the X51 performed about where we expected for its midrange Core i5 quad-core CPU.  It's not a workstation number cruncher but it gets the job done for gaming and multimedia tasks especially, where GPU performance is more critical.  In that regard, gaming performance of the X51 was, for all intents and purposes, the fastest of the bunch among the other full-sized systems we tested.  We gave the X51 a high watermark to hit, pitting it up against full-ATX and mid-ATX systems, and the little alien invaded and cleaned house.

It's not often we're fully satisfied with an SFF PC and though the X51 isn't perfect, in our opinion the folks at Alienware should be commended for putting out an exceptional product.  If they found a way to carve an SD card slot into the front of the system, we would really have been splitting hairs to find any other remotely significant omission.  Beyond that, this small but mighty alien life form is a downright supreme being.  The system is stealthy quiet.  We've seen reports of some other press folks noting that noise can be a factor under load but that definitely was not our experience.  It's a bit of a subjective area but we've heard more than our share of systems and notebooks over the years.  The X51 is definitely offers what we would consider to be a quiet PC experience, whether idling on the desktop or under intense gaming action.

Performance-wise, it's hard to strike a balance between size and thermal capacity within systems like this, but Dell-Alienware had their thinking caps on when they decided to engineer the power supply as an external solution.  Keeping 330 Watts exterior to the system was a smart move and allowed the team to drop a beefier graphics processor in this machine, to help drive frame rates higher in its primary usage environment.  Speaking of which, NVIDIA's GeForce GTX 555 was sort of a sleeper for us.  We expected more middling performance from the graphics solution in a box of this size but once we figured out it was a dual-slot, 288 CUDA core engine in there, we knew there might be a bit of muscle going on.  How much more, honestly, we were pleasantly surprised to see.  The Alienware X51 small form factor gaming system offers full-sized gaming guts and gusto in a tight little package.  This thing has a Napoleon complex and we like that a lot.

Style-wise, though we've said before that Alienware systems can sometimes be a love-it or hate-it affair, we'd be hard pressed to think anyone seeing this sleek little machine would think otherwise.  The X51 is a stylish little black box that will class up any TV room, dorm room or similar setting and it won't take much shelf space to do so.

The Alienware X51 that we tested retails for $999 currently on Dell's site and you can configure a system with various upgrade options from there, which will affect your pricing either north a bit, or much lower if you prefer.  It's not cheap but as the cliche' goes, you get what you pay for.  We think the Alienware X51 is so impressive for small form factor gaming or as a kick-ass HTPC, that we have zero hesitation in giving it a HotHardware Editor's Choice.
  • Powerful machine for its size
  • Sleek, attractive design
  • Extremely quiet, even under load
  • Great gaming performance up through 1080p resolution with high image quality
  • Cool AlienFX lighting effects
  • Relatively low power consumption
  • A little pricey, depending on your config
  • No SD card slot

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