Connection problems and their effects on gameplay :
This forces a play to lead a target in order to get a hit. High ping can be due to long distances, bad routing or some port-level rules applied by your ISP.
Note : In Europe, routing through networks such as telia can cause high ping also.
Up and down ping
Unconstant ping can make the game slightly unplayable. At some moments you are able to play normally and, at others, it is very hard to get a hit or avoid damage.
Packet loss is when information gets lost between the server and you. It is usually an ISP problem. The effects include players warping from one spot to the other with no transition. When packet loss is high, your shots will be heard but won't get registered by the server. It is usually unplayable above 4-5%. No adsl or cable connection should be showing packet loss unless the provider is overloading capacity. You can use a program such as WinMTR to carry out tests.
Irregular speeds can affect the game similar to up and down ping in that game will play ok at some moments and not others. It is hard to detect this as there are no particular telltale signs. However, the game will feel sluggish at times, actions will take place a fraction of a second later and you might miss a stunt or two.
Note : Similar effects can also occur if UT or your graphics driver isn't performing correctly so reinstall these before troubleshooting your hardware.