2010-11-19

What's Mouse DPI and Does It Matter in Real-Time Combat Gaming?

Perm url with updates: http://xahlee.org/kbd/mouse_dpi.html

What's Mouse DPI; Does Mouse DPI Matter in Gaming?

Xah Lee, 2010-11-19, 2011-01, 2011-04-22

Spent about 6 hours tech geeking on mouse again. Watched quite a few youtube videos on reviews of various gaming mouses.

About mouse, there's something i never understood completely. That's DPI (dot per inch). If a mouse has 800 DPI, supposedly it means: if you move your mouse one inch (2.54 cm), the mouse will be able to send 800 signals. However, it's much more complicated than that.

There are these issues involved:

  • There's USB poll rate (aka USB Report rate) Doesn't matter what's your DPI, if the mouse is using USB interface, the USB will get input from the mouse at a fixed rate. (Windows default is at 125 Hz) (actually, it's more complicated than that. It seems that USB has different protocol. One of them does not rely on regular poll, but i read that nobody uses that because it's more expensive.)
  • There's mouse laser scan frame rate. (Microsoft SideWinder X8 amazon says it's at 13k Hz)
  • There's “max acceleration”. The SideWinder X8 says it has “Max Acceleration: 75 G”. Don't know what the heck that really means.
  • There's also the software layer changes sensitivity. That is, how many pixels to move per signal.
  • There's also software acceleration. That is, pixels per signal over time. The faster you move, the more distance covered.
  • The application may over-ride or ignore your driver's settings. For example, in Second Life, your mouse wheel accelation is ignored.
Microsoft sidewinder x8 mouse 2

“Microsoft Sidewinder X8 mouse”, and a recharger with magnetic connector. amazon

Some gaming mouse software automatically sets your USB poll rate to a higher frequency. Some game also have its own software layer for adjusting your mouse sensitivity. The bottom line is, it's really hard to figure out what is your real settings.

I play real-time combat games (aka “first-person shooter”) in Second Life, and never in my life i find the high DPI useful. I have a Microsoft SideWinder X3 Mouse, with DPI at 2k. But that rate is just not usable. I set it to 800 DPI. LOL. I always doubted whether the DPI matters.

Here's a example of a spec, from the Sidewinder X8:

  • Resolution: 250–4000 dpi (BlueTrack™ Technology)
  • Image Processing: 13000 frames per second
  • Max Acceleration: 75 G
  • Max Speed: 120 inches per second
  • USB Reporting: Full-speed, 500 Hz
  • Wireless Play: Up to 30 hours

Does DPI Matter in Gaming Mouse?

Here's a article from arstechnica that confirms my own experience:

Does DPI matter in gaming mice? One mouse-maker says no (2010-02-10) By Ben Kuchera. @ arstechnica.com

Quote:

"Technology has progressed to a level where you can move your mouse, say, one inch on your desk, and your cursor will move 2 or 3 times your screen length. That sounds impressive for sure, but where is the real value in that?" Rom asked. "That doesn't make you more precise or accurate; I would argue that it does exactly the opposite. A higher DPI in a mouse doesn't offer a lot of value, and it is not a benchmark for how precise or awesome the mouse is. It's simply a measure of sensitivity."

Also, if you dig into hardcore combat game articles online, some'll tell you to set your mouse's DPI to the highest, and turn off any software adjustment of mouse sensitivity. So that you have the highest hardware based precision. This makes sense logically. But in practice, 2k DPI is too fast to be usable.

Also, some site i've read even tells you to even turn off the “acceleration” (aka “enhanced pointer precision”). So that, you have a linear correspondence of your mouse movement and movement of the screen, which supposedly makes you aim/combat better. This sounds logical, but i'm not so sure about it in pracitce.

Because, today, mouse technology, the laser tracking, the DPI, and the mouse software layer, sensitivity adjustment etc, all things considered, are quite robust. It's questionable a little “precision” gained from DPI or some training with linear-mouse-screen training would make any difference. The point is, adjust whatever, and as soon as you feel comfortable and habituated with that setting, it should be fine.

Here's some articles from hardcore gamers, especially the first one is fantastic. It also shows that 800 DPI is plenty for vast majority of hardcore gamers (unless you have several monitors connected).

I still don't understand the DPI in complete technical detail, but in any case, i have learned a few things from my readings.

Over the past year, i've tried to un-installed my Microsoft IntelliPoint mouse software and use Windows default basic mouse driver software. In general, i don't find it much of a advantage. Currently, i use do have IntelliPoint installed, because it provides mouse wheel acceleration setup.

The “acceleration” — changing the pointer movement rate depending on speed you move the mouse — is very useful. For example, when working in photoshop or 3D Modeling Software, when i need precision to adjust a pixel, i can move the mouse slowly, and when i need to fly cross to the screen's corner to press a button, i give the mouse a quick push.

Note, if you uninstalled your mouse driver, you can still use AutoHotkey to remap buttons and be app-specific, but you need to have some programing experience to write AutoHotkey files. See: AutoHotkey Basics.

What's the Difference Between Optical vs Laser Mouse?

Both optical and laser mouse use light technology. Optical mouse uses LED, while laser uses laser. Laser tech can track on more surfaces, at higher frequency.