Every new offering from Razer is a special one. Adored by gamers and style-conscious peripheral users alike, there are many people who look to Razer for their needs.

The Razer Lachesis uses a super-accurate laser to track your mouse movements rather than the previous 3G infra-red sensor used by the Death Adder. Boasting an incredible 4000dpi and nine programmable buttons, the Lachesis sounds like one of the best gaming mouses out on the market and today we will find out.

About Razer:

“Razer is the world’s leading brand in high-end computer gaming peripherals. We reinvented the computer gaming industry by bringing the competitive edge to gamers when professional computer gaming was in its infancy. In the mid 90s, with the advent of networked gaming and competitive first-person-shooter (FPS) games, gamers found that their legacy peripherals were inhibiting rather than enhancing their gameplay.”


  • 4000dpi Razer Precision 3G Laser™ sensor
  • 32KB Razer Synapse™ onboard memory
  • Nine independently programmable Hyperesponse™ buttons
  • 1000Hz Ultrapolling / 1ms response time
  • On-The-Fly Sensitivity™ adjustment
  • Variable true dpi setting adjustments in increments of 125dpi
  • Always-On™ mode
  • Ultra-large non-slip buttons
  • 16-bit ultra-wide data path
  • 60-100 inches per second*
  • Ambidextrous design
  • Scroll wheel with 24 individual click positions
  • Zero-acoustic Ultraslick™ Teflon feet
  • Gold-plated USB connector
  • Seven-foot, lightweight, non-tangle cord
  • Approximate size: 129mm (length) x 71mm (width) x 40mm (height)
  • Requirements: Windows® 2000 / XP / X64 / MCE 2005 / Vista / Vista64 Available USB port CD-ROM Drive (for drivers) At least 35MB of hard disk space (for drivers)

The Lachesis comes in the usual Razer box where you can see the mouse in its plastic casing before you buy or open the box. Following the trend of naming their mice after snakes, we found out that the Lachesis Muta Muta, which is the full name, is the name of the largest pit viper in the world. It is rather ironic how Razer name their mice after snakes since they have an appetite for…well, mice. Moving on…

The mouse uses the same rubbery surface that as the Death Adder. It’s used for the top half while the bottom is a glossy plastic. Buttons are in abundance on the Lachesis with two directly behind the scroll-wheel and then another two on either side, covered with the rubbery surface. The main two buttons for left and right click are formed out of a single piece of plastic that makes up the top of the mouse which makes the design look seamless.

The box contains the usual stuff that Razer bundles in with their products, including the certification of authenticity and a manual. You also receive a driver CD that is more than likely going to be out of date due to regular driver updates released via the web.

You can get this mouse in both blue or white, which refers to the colour of the LED’s in the scroll wheel and the rear Razer logo.

The mouse uses an ambidextrous design meaning both left-handed and right-handed gamers can use this mouse.

As you can see from underneath, you have the glossy black plastic which is obviously designed for reducing friction with the help of the Teflon feet. There are three white Teflon feet that make sure the mouse will travel as smoothly as possible on your gaming surface. The front two feet are quite small, while the rear foot is much larger and shaped around the curve of the mouse. There is the usual profile button which allows you to change the software profile without having to refer to the on-screen driver menu. You can also see the optical sensor and some bits of information telling us of its 4000 DPI goodness, which may we add is the highest DPI mouse we’ve used before.

We did find the Lachesis to be a big too big. Our fingers head to be spread out to comfortably click the buttons which we weren’t used to. In fact, it was quite annoying. The side buttons are, however, placed in the perfect spot so that your thumb can easily access them – if you’re right handed.

As this is a wired mouse, you get a cable coming out of the mouse – a tail if you like. That ‘tail’ is 7 foot in this case which is almost certainly long enough for everyone.

Another USB product, another simple installation. With both XP and Vista, the mouse is installed without any hiccups with basic drivers and unlike other Razer mice, the advanced functions work without drivers. The top two buttons behind the large scroll wheel are instantly usable for DPI adjustment, switching between highest and lowest in four steps. The right-hand side buttons change the profile of the mouse up and down, which has no effect apart from flashing the LED’s of the mouse when pressed until the drivers are installed. The other side buttons are forward and backward in your browser which is strange when you first accidentally press one and go back a page on the net.

It sounds like a small deal that the DPI adjustment works without drivers; you have to remember that other Razer mice wouldn’t do this, and you would have to install the drivers and then restart your PC before they worked. Then, if you were to remove the mouse, you’d have to reinstall the drivers before the mouse would be detected again. Thank God that Razer has fixed this annoyance.

The Lachesis comes with something called Razer Synapse which is 32KB of on-board memory. This is where your profiles are stored which means that if you were to take this mouse with you, and plug it into a friends PC, you will instantly have all of your profiles loaded and ready to use, even without the Razer software installed.

Testing & Performance

Due to the ambidextrous design, the Lachesis feels less comfortable than the Death Adder. It’s not uncomfortable, but if an older (and cheaper) product fits your hand better you can see the obvious choice to take. The ambidextrous design obviously sacrifices comfort for either-handed players, which is not really that necessary in our opinion.

There is, however, a more serious issue with the Lachesis. The mouse sensor is no longer an infra-red LED as seen on the Death Adder or Krait but rather a laser version, which is why you have the ridiculously high DPI value. Now that’s not the problem, the problem is the fact that the sensor is faced downwards rather than at an angle like most mice. This isn’t a problem most of the time, but when you use a soft mouse mat and click the mouse button, the cursor moves slightly, which is most likely due to the placement of the sensor. This problem doesn’t occur on a hard surface, and is only present on cloth mats, which makes us believe this is due to the mat bending under pressure and causing the sensor to pick it up as movement. As you can imagine, this gets worse as you increase the DPI setting.

General use isn’t affected greatly, but when it comes to gaming – the main use for this mouse, you have problems. For example, when we tried sniping in Crysis (using a mouse mat of course) it was quite difficult and almost impossible. Thankfully, only mouse mats are affected but it’s still quite an issue. For the record, we used a SteelSeries QcK Heavy as the mouse mat.

Considering this mouse features over twice the DPI of the Death Adder, its accuracy should be unmatched. We personally thought that the additional DPI would make for much smaller movements, but the difference wasn’t quite as huge as we thought, which in our case was good. We do think it will be adequate enough for most high sensitivity gamers, though.

Use the Lachesis on a hard surface and it works brilliantly. You mouse movements are accurately matched on-screen by your cursor, at any DPI setting. In Crysis, sniping is a breeze on a hard surface. Pushing up the DPI using the buttons behind the scroll wheel, you get the additional speed burst you need with no noticeable negative deceleration. On either hard or soft surfaces the mouse travels over the surface like a Razer product should and the Zero-acoustic feet name is rightfully given.


Overall, we were a little let down by the Lachesis. It’s pretty much unusable on a soft mouse mat, and isn’t as comfortable as the previous Death Adder. There are a few advancements, which we welcome like the on-board 32KB memory, mouse controlled DPI setting, driver-less operation and superior laser technology.


  • Looks good
  • High accuracy
  • Razer build quality
  • Driverless operation


  • Near unusable on soft surfaces
  • Not as comfortable as previous Razer mice