There is a lot of (mis)information floating around the web about what’s important when shopping for a mouse. The goal of this page is to give you an intuitive understanding of the various factors regarding mice.
- How much will a mouse cost me?
- Resolution / CPI / DPI / PPI
- Polling Rate / Refresh Rate / Hertz (Hz)
- Tracking Speed / Inches Per Second (IPS)
- Lift Off Distance (LOD)
- Optical vs Laser
- Flaws & Flawless Sensors
- Feet / Skates
- Shape & Weight
How much will a mouse cost me?
Good mice don’t have to cost an arm and a dick, what I consider to be the perfect gaming mouse at the moment only costs $25 on amazon - the Nixeus Revel. Don’t believe the marketing on these $200 mice, use the information on this page to make an informed purchase.
Resolution / CPI / DPI / PPI
First of all, just to clarify:
- DPI (Dots Per Inch): A term used in the printer world to describe how many little blobs of color (dots) the printer can fit in a linear inch
- PPI (Pixels Per Inch / Pulses Per Inch):
- Pixels Per Inch: A term used in the display world to describe the pixel density, also measured in linear inches
- Pulses Per Inch: What people called CPI long ago
- CPI (Counts Per Inch): This is the correct term for mice, like with all the other “per inch” measurements, this is measured in linear inches
There are a few ways to think about CPI, if you google it you’ll get something along the lines of “the number of steps the sensor will report after moving one linear inch”. I think a more intuitive way to think about it is by looking at the extremes. If we have a mouse with 1 CPI that means we will have to move the mouse an entire inch before a single movement step is sent to the computer.
In other words, CPI is the measure of the minimum physical movement of the mouse which will be sent to the computer. You can test this yourself by plugging in a mouse that can be set to 100 CPI (or lower) and very gently moving it. You will notice the discrete steps the cursor takes. A higher CPI means a more accurate representation of the movement will be reported to the computer.
There are two caveats with resolution:
- At some point the movement reported by the mouse will be smaller than the minimum visually noticeable movement on your monitor / in your game. At this point raising the CPI will not produce visual differences. This number depends on your resolution, and your field of view.
- Some mouse manufacturers will use the microcontroller to fudge the numbers that the sensor can actually achieve, check the sensor specifications and make sure it lines up with what the mouse claims. If this is the case, it is likely the mouse will have jitter
A rough estimate for the maximum useful CPI is to look at this extreme example: 4k (aka 2160p) resolution width is 3840 pixels, combine this with a 3D game which defaults you to 60 degrees field of view (borderlands 1?) and you get a total of 3840 * (360⁄60) = 23040 pixels per 360 degree rotation. If you have a very high sensitivity of 4 inches per 360 degree rotation that gives us a maximum useful CPI of 23040 / 4 = 5760 CPI.
Generally speaking, anything above that will not provide a benefit to you. I’ve put those numbers from the example above into this little calculator, give it a shot to see what the maximum useful CPI is for you personally:
Polling Rate / Refresh Rate / Hertz (Hz)
This section is about the USB polling rate, not the sensor refresh rate. I have yet to see a sensor which has a refresh rate slower than the USB polling rate. This is only part of the sensor section because it’s often associated with the sensor.
The polling rate is the rate at which your computer asks your mouse to send an update. I am not a fan of this definition because it doesn’t give you an intuitive concept around the consequences of low polling rates, for that we’ll conduct a little thought experiment in the next paragraph. An easy way to think about the polling rate is by looking at it as the maximum variance in response time. In other words a 125Hz polling rate has a maximum variance of 8ms - This means you will see your cursor respond anywhere between ~0ms and 8ms after the physical movement of the mouse.
We will start our thought experiment with two identical mice with differing polling rates: a 1Hz mouse, and a 1000Hz mouse. If we move both mice one inch on the mouse pad, will they move the same distance on the screen? Yes, they will - even though one is polled once per millisecond and the other is polled once per second, the total distance reported by the mouse will be the same. The real question is: How long will it take for the 1Hz mouse to complete the motion?
The answer is very interesting: it’s possible that the 1Hz mouse actually ends up moving the cursor the total distance more quickly than the 1000Hz mouse. How is that possible? If the 1Hz mouse sends an update and then 999.5 milliseconds later you move the mouse 1 inch another update will be sent only half a millisecond later, whereas if the 1000Hz mouse sends an update then immediately after you move the mouse 1 inch another update will be sent one whole millisecond later. In that exact scenario the 1000Hz mouse is slower to respond than the 1Hz mouse. However, the variance on the 1Hz mouse is extremely high, your response time could be anywhere in the range of ~0ms to 1000ms after the physical movement of the mouse. The 1000Hz mouse will respond anywhere between ~0ms and 1ms after the physical movement of the mouse.
This example is ridiculous, but it helps you understand an important consequence of polling rates: The higher the polling rate, the lower the variance of the response time, and therefore the higher the predictability.
One very interesting subtlety of mouse polling rates has to do with monitor refresh rates. If you have a 60Hz monitor and a 125Hz mouse then the best case visual response time is still ~0ms, if the monitor and your mouse refresh virtually at the same time you physically move the mouse. In the worst case you move the mouse right after a mouse refresh, which then takes 8ms for the next refresh. The monitor then refreshes just before the mouse information is processed so you have to wait an additional 17ms for the monitor to refresh, and finally after 25ms you see the cursor move. So the variance of this setup is between 0 and 25ms. The visual variance of a 144Hz monitor and a 1000Hz mouse is between ~0ms and 8ms.
The key to consistency is predictability, you want to minimize the variance of your setup in order to perform more consistently. Since this isn’t a guide to buying a monitor I will give recommendations for the mouse sensor only: The higher the polling rate, the better, period.
Some nerds might give some crappy arguments like:
To that I say: Show me a computer that will run your FPS game but struggle handling 1KHz polling rate. The human eye arguments really annoy me because they’re just completely wrong. First of all, you can easily disprove this by comparing a 60Hz monitor and a 120Hz monitor, everyone can see the difference just by spinning the mouse cursor in a circle. Second of all, when you play at a very high level your hands will move faster than you can decipher the visual information. If you’re not convinced, set your monitor’s max refresh rate to 30Hz and downclock your mouse to 30Hz… GOOD LUCK!
The acceleration of a mouse sensor is usually rated in g’s, this rating represents the maximum linear acceleration the sensor can undergo and still function accurately.
I used an NGIMU to measure the linear acceleration that I could apply with my arm. I went through some regular motions and then some more vigorous movement; You can see the data in the following video:
In this video I was able to reach an acceleration just shy of 13g. After the video I tried holding the sensor in my hand and moving as fast as I possibly could and was actually able to max out my NGIMU at 16g. I don’t think I was moving much faster than 16g though. This data shows that if you want a sensor which won’t get in your way with “twitchy” movements (like clearing long doors on dust2 coming from ct side) you need a sensor rated for at least 13g of acceleration - to be safe get one with 20g or more since that seems to be the limit of what a human shoulder can produce.
Tracking Speed / Inches Per Second (IPS)
Tracking speed is most often rated in inches per second. It’s the maximum linear velocity which the sensor will accurately record.
I tested how fast I could move my mouse 18 inches and measured the time it took. The fastest time I was able to perform was 0.13 seconds - measured on my phone’s stopwatch. Those numbers give me an average velocity of about 138 inches per second. I moved at a similar velocity as my 13g measurements in the video testing acceleration. My recommendation is to look for sensors rated a little bit higher than that to account for some error in my measurements and also differences in our anatomy.
Lift Off Distance (LOD)
There’s not much to say here, every sensor has a working distance. If you play on low sensitivity or for some other reason find yourself lifting the mouse off of the surface often, then you want a lower lift off distance. I personally play on a very low sensitivity so I look for a lift off distance of less than 3mm. Some sensors have configurable lift off distances. Every mouse will seat the sensor slightly differently so this is more of a mouse specific measurement rather than a sensor measurement.
There is a trick you can do by taping the sensor aperture which will lower the lift off distance at the expense of other mouse specs. I recommend using this as a last resort, instead look for a mouse with the right lift off distance for you.
Optical vs Laser
The only reason this should influence your decision is due to which surfaces these mice work on. An optical mouse works by shining visible or IR light to illuminate the surface, as you can expect it struggles with reflective, and translucent surfaces. Laser mice generally use light as well, but in a laser to illuminate the surface and generally perform much better on reflective and translucent surfaces. There are different laser technologies though, even within the “laser” category you will find some work better than others on some particular surfaces (like mirrors or whatever kids are using for mousepads these days). I haven’t seen a sensor that doesn’t work on a cloth mat.
Flaws & Flawless Sensors
Some sensors, or sensor firmware, or microcontrollers introduce “flaws” into the output of the mouse. If there is any distortion of the signal that the sensor or microcontroller receives and it cannot be disabled, then it is a flaw. You want to look for a sensor which has none of the following issues:
Pointer Acceleration / Tracking Speed Inconsistency
Not to be confused with the sensors rated acceleration, this has to do with the output of the mouse. If your mouse has pointer acceleration then the distance pointer moves on the screen is a function of both the physical travel of the mouse and the velocity which the distance was travelled. Some people add pointer acceleration through software, which is perfectly fine - but you absolutely do not want it built into the hardware you purchase. Pointer acceleration will make it harder to develop muscle memory.
Some sensors have differing sensitivities (maybe due to CPI distribution?) on different axes. A mouse should work the same regardless of the axis it’s moved.
Prediction / Drift Correction / Angle Snapping
Some mice will try to correct your nearly horizontal or vertical movements and report them to the computer as true horizontal or vertical movement. In other words if the mouse thinks that you are trying to move in a straight line it will kindly tell the computer you’re moving in a straight line. Some people like this feature, most people do not.
Some mice use either extrapolation or other techniques to claim higher CPI numbers than the sensor is actually capable of. Often this causes the movement to feel as if they’re moving a little bit too far, or a little bit in the wrong direction.
Feet / Skates
Most people want feet with the lowest amount of friction to the mousepad. Generally speaking PTFE (also known colloquially as TeflonTM) is a good choice for mouse foot material since it has an incredibly low coefficient of friction.
There are some people who prefer more friction, if you are one of those people I recommend looking into “control” mousepads. Usually they are metal with a coarse surface. If you use one of these pads your feet will wear down more quickly.
When looking at mouse feet, one thing we should note is that friction is independent of surface area. So in the friction case size does not matter. However in the case of wear - the larger the mouse foot, the longer it will take to wear down. Many mouse manufacturers will sell you replacement feet, there even exists a 3rd party market for feet (see Hyperglide).
If there is a mouse which is perfect for you but uses a crappy material for the feet or the feet have worn out and you can’t find replacements, you can purchase a roll of PTFE adhesive tape (solid not woven). This tape is basically a very thin amount of PTFE which you stick right on top of your mouse feet and use a razor blade to cut it down to size. This will perform just as well as solid PTFE feet, but will wear down quickly depending on the material your mouse pad is made of.
Many of you may already be familiar with the concept of switches from your fancy mechanical keyboards, well it’s the exact same for mice. There are different manufacturers for the switches, however, it isn’t a very hot topic of debate. Cherry of the mechanical keyboard world is analogous to Omron in the mouse world. Omron makes two types of switches, one with a 0.6 newton actuation force, and one with a 1.2 newton actuation force. If the sensitivity of the mouse switch is important to you then you should pay attention to which switch your prospective mouse has. You can differentiate these by the color of the plunger on the switch itself.
The scroll wheel is technically also a switch. To my knowledge there is no Omron or Cherry of the scroll wheel world - although many swear by Logitech’s “infinite” scroll wheels.
Shape & Weight
There are 3 common ways to hold a mouse:
- Palm Grip - Your entire palm through the fingers lays on the mouse surface
- Claw Grip - The base of the palm and the finger tips lay on the mouse surface
- Fingertip Grip - Only the fingertips lay on the mouse surface
My personal recommendation is to measure from the middle of your palm to the tip of the longest finger. For palm grip the mouse should be at least that long. For claw grip it should be at least one inch shorter than that. For fingertip grip it doesn’t matter what the length is. The shape of the mouse can play some role in the sizing too so check the reviews on the particular mouse you’re looking at if you think it might be an issue.
The weight of the mouse is a debated topic. Some companies market heavy mice, some market light mice, and some market adjustable weight mice. The physical consequences of a heavy mouse are: more friction, slower acceleration of mouse. Some people argue that this gives you a more accurate mouse movement… I don’t buy it. I think a heavier mouse actually makes you less accurate in the same way a dull knife makes you less precise. The less effort it takes to make the movement, the more you can focus on the quality of the motion. There is a very small difference in weight between the heaviest and lightest mice, so it likely makes a very small difference in performance - pick what’s more comfortable.
If you’re having wrist problems and want a mouse that will help you prevent further injury then I highly recommend a vertical mouse. Unfortunately there aren’t any performance vertical mice on the market - all the sensors in use are garbage. The best one I found in my years of gaming with a vertical mouse was the Delux M618LU. There are many versions of this mouse, but this particular one uses a decent sensor, I’m not sure what it is but it has a medium acceleration (around 10g). If you’re looking to game on a vertical mouse that’s what you need. The best thing you can do for your wrists is strengthen them, handstands and ring holds will give you iron wrists. I recommend that method over any vertical mouse.
Some mice will have software you can download which will allow you to change the settings on the mouse such as: color of LEDs, CPI, and macros. Other mice will have dedicated hardware buttons for some or all of these functions, if these are important to you check the manufacturers website for software or see if it’s in the feature list.