Alienware X51




  • Good mid-range specifications
  • Suitable for 1080p gaming and VR (GTX 970 model)
  • Slimline desktop chassis design


  • Compact design increases heat and noise
  • Relatively expensive

Key Features

  • Review Price: £1000.00
  • 6th-gen Intel Core i5 or i7 processor
  • 2GB Nvidia GeForce GTX 960 or 4GB GTX 970
  • 16GB DDR4 memory
  • Opitonal Samsung PM951 256GB SSD
  • 1TB or 2TB hard disk
  • VR-ready (GTX 970 model)
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What is the Alienware X51?

Alienware is one of the strongest global brands of gaming PCs, with a range that now stretches to multiple mobile and desktop form factors. While many gaming PCs come in giant towers, the X51 packs a top-of-the-line CPU and mid-range graphics into a desktop chassis that’s not much bigger than a current-generation console.
The X51 line has been around for a while – Trusted covered the previous version back in September 2014. This update is really more about introducing up-to-date technology and a spec boost than a radical design overhaul. Our original criticisms of the previous version focused on its specification, which wasn’t capable of gaming beyond 1080p resolution, lacked an SSD and lead to some toasty internal temperatures. Have these issues been resolved with new-generation hardware?

Related: Best PC games 2015

Alienware X51 – Design

The X51 is all about squeezing a capable gaming PC into a console-sized chassis. As with previous versions, its dimensions make it only slightly larger than a PS4 or Xbox One, with a width of 9mm and a height of 343mm (in vertical orientation).
If you’ve worked in an office at any point over the last decade, there’s a high probability you’ve used one of Dell’s slim corporate desktop systems, and the X51 borrows heavily from them. It has two sets of rubber feet for both vertical and horizontal placement. A glossy plastic cover runs around the side, featuring the iconic Alienware logo on the front that illuminates in blue, along with a plastic section at the top that’s illuminated with LEDs.
Alienware X51
The edges are curved at the front. The power switch sits on the right, its status indicated by a white LED. There are two front-mounted USB 3 ports and audio, but notably, the optical drive of last year’s model has been given the chop. This reflects the modern dominance of cloud services such as Steam and Origin for gaming.

Related: Best gaming headsets 2015

Alienware X51 – Specifications

Quad-core Intel Skylake processors are the new performance champions for PC gaming, if only by a disappointingly slim margin over the previous Core i7-4790K Devil’s Canyon chip. The X51 comes with a Core i7-6700K, but by default, it doesn’t run at its full 4.2GHz Turbo Frequency. Instead it’s limited to 3.9GHz, the lower clock speed is intended to keep down internal temperatures, which can be potentially problematic in small chassis gaming desktops.
The Alienware Command Centre software makes it easy to change this, however. With this R3 version of the X51 – there are four listed on Dell’s site – the CPU has an all-in-one liquid-cooling system that allows that clock frequency to be raised to 4.4GHz. This software also lets you fiddle with various settings – the Alienware FX mode, for example, which changes the colour of the LEDs on the top of the unit.
As with last year’s PC, Alienware has chosen a mid-range graphics card for the X51. The “Maxwell”-based Nvidia GeForce GTX 960 is a slight improvement over the Radeon R9 270 in the previous machine. It only has 2GB of GDDR5 memory, which isn’t a huge amount by today’s standards, but enough for solid 1080p performance. This card comes with 1,024 stream processors, 32 ROPS, 64 TMUs, a base clock of 1,127MHz and memory frequency of 1750MHz.
 Alienware X51
Related: Best gaming laptops 2015

It has 16GB of DDR4 memory, running at 2,133MHz. There’s also a 256GB Samsung PM951 PCI Express SSD, plugged directly into the motherboard’s M.2 slot. PCI Express SSDs come in all shapes and sizes, offering wildly different performance figures. Samsung’s 950 Pro is the current king by a long way, with read and write speeds of well over 1GB/sec; the enterprise-grade SM951 isn’t too far behind.
The PM951 isn’t quite as good, though. While it’s a PCI Express Gen 3.0 device including NVMe support, with quoted read speeds that are an impressive 1,000MB/sec, the 280MB/sec write speeds lag behind normal 2.5-inch SSDs. It’s inclusion is probably down to saving internal space from the small M.2 form factor, rather than the performance. But those read speeds are still very nice indeed.
Additionally, there’s a 2TB Seagate hard disk, an obvious essential for a large library of games or media.
Windows 10 Home comes as standard on all X51 configurations and Steam comes preinstalled as well. During testing, I was cursing Dell’s inclusion of the McAfee antivirus trial, which had expired and kept popping up during benchmark runs requesting I pay them money. Not a chance, matey.

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