The paper deals with practical and theoretical investigations of the PA 6 high speed fiber spinning process in the velocity range from 3000 until 5450 m/min by means of tensile force measurements in the spinning line below the fiber solidification point. The measurements were evaluated under thr ee different goals as follows: Quantitative determination and interpretation of relations between the technological and textile-physical fiber parameters spinning speed throughput, and fiber fineness (in the range of 4.1 to 14.8 dtex for a single filament spun from a 9-holes die). Comparison between the experimentally measured and the theoretically calculated tensile forces by means of the own fiber formation model developed in the last years. On this occasion a satisfactory concordance could be noticed between the experimental and theoretical results. In addition to this a good model parameter estimation could be proved in the force balance part of the differential equation system for the fiber formation. Spectral analytical evaluations of the measured tensile force time functions by means of their autocorrelation functions. It could be demonstrated, that higher frequency tensile force disturbances could be caused both by the spinning pump and by unevennesses in the cross quench air conditions below the spinning die. All results from the investigations above are discussed in relation to different technological process goals and their realization possibilities.