As a PC gamer, I am often torn between a desktop computer and a gaming notebook.

A desktop PC is generally more capable, offers an upgrade path, but takes up more space.

On the other hand, a laptop is mobile, but offers less performance for your dollar.

The Asus ROG XG Station 2 graphics dock solves this dilemma by boosting the graphics performance of a laptop with a desktop-class graphics card.

This dock, an angular chassis roughly half as tall as a standard mid-tower PC casing, contains a single slot for a full-size graphics card. Its built-in 600W power supply is more than sufficient for the latest high-end graphics cards from AMD and Nvidia.

It is probably also good for the next few iterations of graphics cards, seeing as how the trend is towards power efficiency.

Press a switch at the top and the chassis opens down the middle to give access to the graphics card. Asus has equipped the chassis with cooling fans, as well as LEDs that bathe the graphics card in a red, pulsating glow visible through the transparent side window.

In addition to the Thunderbolt 3 port that connects to your laptop, the dock can support external storage drives and other devices like mice via its four USB 3.0 ports.

A Gigabit Ethernet jack also adds wired connectivity to the attached laptop. These ports are handy for modern notebooks that often lack such connectors.

The dock itself does not include a graphics card. You'll have to purchase and install your own card. My review set had a Nvidia GeForce GTX 1070 pre-installed.

Although it is marketed as an accessory for the Asus Transformer 3 Pro hybrid laptop, the XG Station 2 also works with Thunderbolt 3-compatible computers from other manufacturers.

So far, I have been successful in getting the Asus dock to work with two ultrabooks - the HP Spectre and the Razer Blade Stealth.

All I had to do was to ensure that the laptops had the Thunderbolt 3 drivers installed.

Windows 10 automatically grabbed the appropriate graphics driver after detecting the XG Station 2, though I would recommend installing the latest AMD or Nvidia drivers for the best performance.

I tested the GTX 1070-equipped XG Station 2 with the Razer Blade Stealth, which has a low-power dual-core Intel processor. The Alienware 17 gaming laptop - with a similar GTX 1070 graphics chip, but a quad-core Intel chip - is used for comparison.

In Crysis 3, the XG Station 2 managed around 70 frames per second (fps) at Very High setting and at 1,920 x 1,080 pixels. This was lower than the 85fps on the Alienware 17.

The results were similar in Doom. The Alienware 17 was faster (116fps) than the XG Station 2 (76fps). Perhaps the slower processor on the Razer laptop, as well as processing overheads over the Thunderbolt 3 interface, affected the scores.

Nevertheless, the performance boost from the graphics dock is significant. These games would not have been playable on the Razer ultrabook without it.

Asus is not the first to launch a graphics dock. Alienware did so a few years ago with the Graphics Amplifier ($419), though it used a proprietary cable and supported only select Alienware laptops.

Last year saw the introduction of the Razer Core, which would have been Asus' closest competitor, if it was available here. Like the XG Station 2, the Razer Core uses the Thunderbolt 3 interface. It even has identical ports. However, you can buy it only in the United States at US$499 (S$700).

At $888, the Asus ROG XG Station 2 is a hefty price to pay to upgrade your laptop's graphics prowess. An additional $400 to $500 is required to get a mid-range graphics card. At this point, you might as well just buy a desktop PC instead.

When I first heard of this graphics dock, I was immediately sold on its potential as a gadget to declutter my desk while still providing an upgrade path for my laptop.

I was further encouraged by the ease of use and the lack of any serious bugs. However, its asking price will likely deter me and many gamers from giving it a shot.

• Verdict: This graphics dock works as promised to boost a laptop's graphics performance. But it carries a hefty price tag.