For most players, 256 is going to cause too much latency. I do all my tracking at the 64 setting. That yields very slight latency(which doesn't bother most players) but it does put more stress on the computer. That's why it pays to use a computer that is above the minimum spec. Here are some basic "lessons" on latency:
#1- it can be caused by a few things:
A-the playback buffer(smaller number=less latency)
B-sample rate. This will give less latency, BUT will tax the computer more if you compare 48K to 96K
C-plugin latency. Some plugins have little to no latency while others could have hundreds or thousands of samples worth of latency, so choose wisely while tracking. If you set your MIX window to show Delay Compensation(View>MIX window shows>), then you can see numbers along the bottom of the MIX window showing latency caused by plugins. Look to keep that number very low while recording(like under 10-15 samples). If you see big numbers of Delay Compensation, make those plugins inactive while tracking.
#2-latency can also be caused by bad routing(which confuses the Delay Compensation). The best example of this would be having a send on the track you are recording, but that send goes nowhere.
System tweaks can make or break performance, so don't ignore them. Hope something here helps
