Polyester mixed yarns with fine filaments

A mixed-filament polyester yarn comprised of fine filaments and fatter filaments that differ in denier but are of the same polyester polymer, wherein said fine filaments are of filament denier 0.2 to 1, said fatter filaments are of higher filament denier more than 1, and wherein the ratio of the average filament denier of said fatter filaments to the average filament denier of said fine filaments is in the range 2:1 to 6:1, wherein the polyester polymer is of relative viscosity (LRV) in the range of 13 to 23, of zero-shear melting point (T.sub.M.sup.o) in the range of 240.degree. C. to 265.degree. C., and of glass-transition temperature (T.sub.g) in the range of 40.degree. C. to 80.degree. C., and wherein the yarn has an elongation-to-break (E.sub.B) of 40% to 160%, a tenacity-at-7% elongation (T.sub.7) in the range of 0.5 to 1.75 g/d, and shrinkage values such that the thermal stability value (S.sub.2 =DHS-S) is +2% or less, and the (1-S/S.sub.m) value is at least 0.1, where S is the boil-off shrinkage, S.sub.m is the maximum shrinkage potential and DHS is the dry heat shrinkage measured at 180.degree. C., and the maximum dry heat Shrinkage Tension (ST.sub.max) is 0.2 g/d or less at a peak temperature T(ST.sub.max) that is in a range of 5 to 30 degrees above the glass-transition temperature (T.sub.g).