Latency is an issue with all DAWs, and is the term used to describe the time taken for an analogue audio signal to be converted to digital, processed, and then converted back to analogue again. While latency normally isnt a big problem for effects plug-ins when mixing, in some circumstances it can cause difficulties, and when playing virtual instruments, any latency of more than 10 milliseconds or so is very off-putting for a performer.
So how do you improve on system latency? A good place to start is the adjustment of your audio settings. Firstly take a look at the buffer size reducing this will reduce latency, however lowering it too far can cause clicks and other noises during audio playback, so then try increasing it slowly until these disappear. If you cant satisfy your latency requirements in this way, more drastic action is required! Either improve the performance of your computer itself, or add some separate DSP processing as we discussed earlier.