Asus has upgraded its powerful but impractical ROG GX700 liquid-cooled gaming laptop by squeezing in a second graphic chip.

In the new ROG GX800 are two of Nvidia's latest GeForce GTX 1080 graphics chips, compared to a single GTX 980 on its predecessor. On paper, this makes the GX800 more than a match for high-end gaming desktop PCs.

Other upgrades include a 4K (3,840 x 2,160 pixels) IPS display with Nvidia's G-Sync feature and a mechanical keyboard with RGB backlight illumination.

The GX800 is expected to launch here in October, but I managed to test a pre-production sample for a couple of days.

My initial impression: this laptop is even more unwieldy than the previous version.

The laptop has ballooned in size and weight. It now has a 18.4-inch screen, up from 17.3 inches on the GX700. The GX800 weighs 5.69kg, or almost 2kg heavier than the older model.

Like the GX700, the GX800's full potential is unlocked when connected an external liquid-cooling dock (dubbed Hydro Overclocking station). This allows its graphics chips and CPU to be overclocked to run at a higher speed than they are able to without the dock.

This dock contains cooling fans, radiators and a pump that circulates the coolant inside the laptop when attached.

At 4.7kg, the dock seems as heavy as before. Unfortunately, the process to attach the laptop to the dock is also as awkward as before. Align two pins on the dock with two holes at the bottom of the laptop, then press down on a large metal switch to lock the dock to the laptop. You cannot detach the laptop from the dock willy-nilly - you have to press a button first to unlock it.

Both the laptop and the dock have their own separate power adapters. These are massive bricks that together weigh 1.28kg.

The GX800 is transported in a trolley case - Asus also includes a backpack for the laptop.

While the dock seems unchanged, Asus says that the internal cooling system for the GX800 has been redesigned for its dual graphics chips.

The GX800's mechanical keyboard does not quite reach the clickety-clackety feel of my own mechnical keyboard, but it is still very decent. Asus says the key travel is 2.5mm, compared to less than 2mm on other gaming laptops.

Installed on the GX800 is the Asus ROG Gaming Center, a one-stop location to monitor and tweak the laptop's settings.

Perhaps because of its prototype nature, the ROG Gaming Center on my unit did not let me manually adjust the clock speeds for the graphics chips and CPU. Instead, I could only toggle between normal and optimised settings.

Despite this, the GX800 produced very impressive results at optimised settings. In Crysis 3, the GX800 scored 73 frames per second (fps) at Very High setting at 3,840 x 2,160 pixels. The Asus G20 desktop (with a single GTX 1080) managed 60 fps at 3,440 x 1,440 pixels.

In the graphically-intensive Doom, the GX800 managed 50 fps at 3,840 x 2,160 pixels with Ultra setting enabled. This was not as fast as the G20 desktop (86fps), though the GX800 was running at a slightly higher screen resolution.

More importantly, the laptop's keyboard felt cool when it was running a game while docked. Only the sides of the laptop felt slightly warm.

According to the ROG Gaming Center, the temperature of the CPU was around 77 degrees Celsius while the graphics chip was at 70 degrees. These readings shot up once I removed the laptop from the dock. The graphics chip was close to 80 degrees while the CPU went up to 90 degrees.

Without the liquid cooling from the dock, the laptop's internal cooling fan also started whirring and became fairly noisy.

Asus has not revealed the actual pricing for the GX800. But given that it has two high-end graphics chips, you can expect the GX800 to cost significantly more than the GX700 ($6,198), which only has a single graphics chip.