I honestly don't think it will make any noticeable difference, and it's not magically going to make your aim better.

The only situation I could see a higher DPI helping is with a low sensitivity, where you will move the mouse a far distance really quickly. It might prevent skipping and not accurately picking up all the movement, but it's all theoretical.

Read on some forum--

Also read that DPI is just a marketing gimmick to make the mouse more expensive than a 2000DPI while a 5600DIP can be three times as much.

Yeah but you can just change your windows sensitivity.

All I heard is that dpi makes the mouse movement smoother overall, so there's no reason to NOT use the highest possible setting. It doesn't matter too much to me what my dpi is cause I can get the same sensitivity by changing windows and in-game sensitivity. I was just curious, but it seems like it doesn't make much of a difference either way.

A lot of mouse sensor actually malfunction at high DPI (postive/negative accel, jitter, etc)

http://www.funender.com/quake/mouse/index.html

put your shit in and it will spit out a useful dpi

It's for quake though, not sure if that changes much but it should give you a rough estimate of what you should use.

At both very high and very low dpi mice sensors tend to have problems tracking. Many mouse sensors tend to have decent performance ~1000 dpi, but each sensor is different. Some tend to work best with various multiples of some number (like 100, 150, 200, etc.) as well. To get a real answer you would be best off googling "{your mouse} sensor" or something similar to find forum posts by people who care way too much about mice. Hopefully from these sites you can find out the range your sensor works best at as well as any other non-ideal problems with your sensor such as mouse acceleration.

The general rule of thumb is pick a dpi that feels nice when you are on your OS (and not in game, since the OS sensitivity options suck for all OSs) and that should work just fine.

use w/e DPI you are comfortable with ON YOUR DESKTOP. other than that, it doesn't really matter.

You mean a lot really shitty mouses do that.

With m_rawinput 1 there's no reason for you not to use the highest DPI available and adjust the Windows sensitivity slider to compensate for normal desktop use.

there is a certain useful dpi that it does not make sense to go over and it is based off of your resolution and sensitivity

somebody please link the phoon mouse guide

also if you want 1:1 mouse movement please dont ever move your windows slider off 6:11

You'd be surprised about how very few good mice there is (mostly the sensor's fault). Here is a link for you because I don't feel like explaining everything :

http://www.esreality.com/index.php?a=post&id=2024663

To make a lil tldr though : Lot's of mice have innate issues or they start to malfunction at a certain speed

With m_rawinput 1 that's irrelevant because it bypasses your windows mouse settings

Yeah, AKA shitty mice.

Pretty much what drew said. Using too low of a dpi on a deathadder causes negative acceleration. It's usually best to use the highest dpi available. I usually just look up what OCN has to say on the mouse.

Example on deathadder.

http://www.youtube.com/watch?v=nrV_E4IkVwM

does the deathadder really function best at 3500 dpi? Or, should I use 1800? I know 450 is glitchy from above video but I want to know about the second to highest setting, because I've experienced some weird insensitivity on very fast swipes with it.

I think deathadder is the one of the few that doesn't function best at max dpi. I've read a bunch on OCN that 1800 is best on the 3.5 deathadders and from using the mouse for about 3 years.

I've got the Zowie eVo EC2 now and use it on the middle sensitivity, not the max setting, because I don't really feel a difference but at my level it probably doesn't matter.

I have my MX518 set at 1800 dpi.

That might be why I'm so horrible.

phoon's old website used to have a great explanation for this. Essentially if you use a generally high sensitivity, it's useful to have your dpi set to a higher number. otherwise, let's say you have a 6" 360, you could potentially notice that your cursor will skip a number of pixels even when moving as little as possible. However, the usefulness of using high dpi to avoid pixel problems ends when your sensitivity is generally pretty low to begin with, especially because a high dpi and a low sensitivity is a recipe for negative mouse acceleration. I'm pretty sure raw input makes this a nonissue, however. Before raw input was released, ~12" 360 and higher with something like 1800 dpi would have negative acceleration issues.

so general rule of thumb for me would be if you use a generally low sens, don't bother with raising dpi. if your sensitivity is pretty high, however, it's useful to use a higher dpi to minimize problems with pixels.