Deep drilling can be a pain.

Going by the spreadsheet I made up, a 5mm standard point dull drill in alloy should need a maximum 450N of thrust at a feed rate of 0.1mm a revolution (a 5mm drill will probably need a lower depth of cut, but it depends on the drill type you're using). A similarly dull split-point drill will only need a max of 350N.

Make sure your feed rate is high enough, otherwise the drill will rub more than cut, causing excess heat and alloy build up on the drill, greatly increasing the thrust required. You want the drill to make a continual definite cut.
Play with the peck depth, as you need to ensure the drill is cleared at deeper depths. If the drill clogs, then it's a recipe for lost steps.

If you're doing lots of these, then you may want to consider doing some manual coding.
Start of with a simple single drill to a depth just before clogging becomes an issue (2 x diameter is a good start), then start a peck cycle at that depth. You may want to use more than one peck cycle, with a full retract between them.

A couple drops of some proper cutting/tapping fluid will help avoid alloy build up on the drill, and improve chip clearance.