Do emulators slow down you Android phone?
Most emulators (namely reputable ones made by real emulator devs like nes.emu, snes9X, gba.emu/gbc.emu, muppen64, epsxe, ppsspp, nds4droid, dolphin) will not slow down your device as they wont be installing anything "extra" with it that could/would be running in the background. Not that ones not listed will slow your device down, but im sure there are some in which have less then noble motives behind them. (as can be the case with ANY software or apps on the internet). But no, an emulator should not be installing anything in which would be running in the background slowing your device down. The only time it should be running any kind of processes is when you are physically using it. And if you have the emulator open with a game and dont close it, it can slow down your device as it will still be using cpu cycles and ram. Emulators also generally dont take up much storage space either (games may, depending on system and how many u store). TLDR: no they dont
How to improve DS emulator speeds and lag?
NO$GBA is a faster emulator. DeSmuME lags even on fast computers. If you really want to use DeSmuME, here are some advices: * Get the latest version (0.9.6), it's faster than the old ones. * Do not apply any Magnification Filters (just set it to Normal). * Set 3D Settings to SoftRasterizer. * In Sound Settings, you can make it Linear (this will reduce the sound quality a bit, but it should make things a bit faster) if you want to. * In Frame Skip, enable Limit framerate. Also, enable Auto-minimize skipping, and choose 9. This should give the best speed the emulator can offer, with limited frame skipping. It is possible to make the speed above 100% during some parts of the game by disabling the "Limit framerate" option. In general, NO$GBA 2.6a is a better emulator.
Dolphin emulator Android??
you need to put your games in a folder somewhere on your device (say roms/gamecube on your SD card). Id HIGHLY recommend you transfer the games from your pc to your phone, rather then downloading them on the phone itself. After you have them on your SD card in a location you know. Open dolphin and set your directory to that which you put your games in. It should then show up (they need to be in .iso or .gcm or .gcz format. NO OTHER format will work. if its a .zip or .rar extract it on your pc first and you will get one if those file types) But know no phone will play GC games for a VERY VERY VERY long time. (id say 5-10 years. WII will take 20+). This is because to get even the lesser demanding GC games to be at "playable" speeds (70-95%) you need atleast a 2.4ghz dual core cpu. And for the very demanding games it can take 3.0ghz+ to get playable speeds. For 100% speed in all games id say you probably need a 3.6ghz dual core or better. Dolphin is only able to use 2 cores max, so having more cores doesnt help speed at all. (and phones are usually multi core cpus at very low clock speeds). Becuase of this, i believe it will be atleast 5-10 years before games are playable on a phone.
Why does emulation on android suck?
I agree with the other answer, I have an Xperia Play (Playstaion phone) which uses android. No problems at all running emulators, even more advanced emu's like ps1 and n64 generally run decently with some exceptions.