We systematically study the strain effects on high-field carrier velocity (v) in (100) and (110) short-channel n/pFETs by means of substrate bending experiment. v and Idsat increase by strain is determined not only by low-field mobility (μ) enhancement (Δμ/ μ) but also by the modulation of saturation velocity (vsat). It is found that v sat increases more by strain in smaller-Δμ/ μ devices. The difference of Δ μ/ μ is compensated by vsat change. As a result, Δv/v of (100)/(110) n/pFETs converge in sub-30nm regime. The superiority of (110) CMOS to (100) CMOS is maintained in terms of both Idlin and Idsat at highly-strained conditions.