We measured the differential insertion loss and the deterministic jitter for three types of differential transmission lines on a motherboard in a serial backplane bus at 2 Gbps in order to prioritize the design specifications for transmission lines. We tested three line widths having different common impedances of the lines while keeping the differential impedance at about 100 Omega, moreover varied the open stub lengths of the signal via holes. In the microstrip line, the loss and the jitter slightly depended on the line width; however, in the stripline, the loss depended on the line width and the deterministic jitter decreased almost linearly as the loss of the stripline decreased even when the impedance of the lines or the open stub length of the via holes was mismatched on the backplane. Therefore, loss design of a differential stripline pair on a motherboard is more important than impedance design in the low jitter.