This is kinda a blog post to vent some steam about my frustration with people and their high DPI mice.
So what I'll basically be doing here is explaining what DPI means and how it affects our computing experience, then I'll tell you all about the current trends in top end mouse products and why (I think) high DPI mice are just using DPI as a gimmick to suck you all in.
What Is DPI?
DPI stands for "dots per inch" (otherwise known as CPI or "counts per inch", which is probably a better term) and the way it works is, a mouse will record a "step" (think of the step as the dot part of DPI) after it has been moved a certain distance. This step is fed to your computer to tell it to move the mouse cursor one pixel.
So one step (or dot) = one pixel. If you have a 1600 DPI mouse, you need to move it just 1/1600th of an inch before your cursor moves one pixel. To look at it another way, move your mouse one inch and you will move your cursor across 1600 pixels. This dot to pixel relationship will be very important later on.
If you have a lower DPI, you will need to move your mouse further before it registers a step, and the opposite is true for a higher DPI mouse.
The other thing to consider is software interpolation. If the Windows mouse sensitivity is not set on the middle notch and / or mouse acceleration is enabled, then you will not get the 1:1 dot to pixel ratio. With mouse acceleration this ratio will always vary depending on the speed you move the mouse at. If you decrease the mouse sensitivity in Windows, you are essentially dividing, which will always have rounding errors. This is not ideal but it still gives adequate accuracy (rounding errors are tiny). If you increase the mouse sensitivity in Windows you will be in trouble. Increasing means multiplication. Let's say you double the mouse sensitivity in Windows. Your 1600 DPI mouse still reports a step after moving 1/1600th of an inch but Windows interpolates this as 2 pixels. That in itself is fine, but what if you move the mouse 1/3200th of an inch? Nothing happens. Your cursor cannot move less than 2px at a time. Same sensitivity, but less accuracy.
The DPI Race
Mouse manufacturers nowadays seem to want to cram the highest possible DPI sensors into their mice. This is basically just a marketing gimmick. People read "8000 DPI" on the box and think the mouse will perform better than the lower DPI mice.
Now don't get me wrong, higher DPI has its uses. If you have a super high resolution screen, you'll have more pixels crammed into your monitor than most, and so your pixel density will be higher (think about the Retina MacBook Pro). In this situation, a higher DPI mouse will allow you to maintain a decent sensitivity, the goal being you don't need to move the sensitivity notch up from the default position - you keep the 1:1 ratio. That and if you really hate moving your mouse, a higher DPI will let you move your cursor a great distance without much hand movement. It can also be useful for DPI switching in a game like CoD when you get stunned by a grenade and the game forces your sensitivity lower. But I don't DPI switch and I still win 9/10 games and I am a seasoned CoD player, so it isn't neccesary.
Why It Is Silly
All that is fine and dandy but the important thing to remember is higher DPI does not make a better mouse. After a certain point having a higher DPI is useless. Try using an 8000 DPI mouse with a 1080p monitor without lowering the sensitivity. Yeah, it is almost impossible to control. Try it at 1440p... that's right, still out of control. 8000 DPI is useless for just about all practical purposes. It's probably even too sensitive for DPI switching purposes.
But the big issue I have with high DPI mice is not how irrelevent they are, it is what is compromised in order to achieve this higher DPI. That's right, I have a big problem with laser sensors. Laser sensors have always been able to accomplish higher DPIs than optical sensors. On the box, laser mice look way better than optical mice due to the whole DPI comparison thing but that simply is not the case. Ask around on enthusiast forums and you will realise that most professional competitive gamers (the guys that get paid large sums of money to win) use low DPI optical mice due to their better perfect control speeds and lack of acceleration (many actually use a Windows Mouse Optical, which is more than 10 years old and has 450 DPI - I've tried it and it works great for low sensitivity uses). Laser sensors usually have positive or negative acceleration. They have a higher "control speed", which means you can move the mouse faster than an optical mouse before it can't register movement anymore, but from my experience they usually have a lower perfect control speed, so they start to experience acceleration issues before optical mice do. Again, don't get me wrong, there are plenty of optical mice with the same kinds of issues (usually cheap ones), but at least a few of these issues are inherent in all laser mice (including expensive ones). Optical mice also don't work on glass surfaces like a few laser mice do but if you're reading this, you shouldn't be using such a surface...
In the end, it is best to ignore the packaging and marketing and look at ALL of the numbers before you make your decision. If you are a low sensitivity gamer, you should realise that 1600 DPI is more than enough (I'm a medium-low sensitivity gamer and I use 1050 DPI at 1440p with the sensitivity two notches down and at 2.5/10 or 3.5/14 in CoD) and you should be far more concerned with jitter and perfect control speeds than anything else. If you are a casual gamer or high sensitivity gamer (yes, I'm putting you guys in the same bracket, hahah) then by all means use the DPI that you require but just remember that if you have to notch the sensitivity down, you're just wasting DPI.
Phew, that's a lot of stuff I just wrote. I should probably add that some of it is based on my experience with mice and is down to personal taste and is aimed at FPS gamers more than anyone else. I just hate seeing people ask on forums about the best mouse to use for their purposes and everyone gives completely wrong facts and the guy ends up getting his 5th high DPI laser mouse and hates it and wonders what's wrong with his aim.