It is quite difficult to measure and compare latencies in GSM and GPRS used as a bearer for WAP. The data rate capacity in GPRS is dependent on many different factors e.g. 1) the maximum number of time slots available for GPRS use, 2) the maximum number of time slots WAP terminal is capable to use, 3) the number of active simultaneous GPRS users sharing the same time slot capacity, 4) amount of data they are trying to transfer at the same time and 5) GPRS efficiency of the service application architecture.
As an example of differencies between GSM and GPRS as a bearer we have estimated the delay to receive the first WAP page (home page) with different methods. Delays are 7-15 seconds (GSM Circuit Switched Data), 5-10 seconds (GPRS on when needed) and 3-5 seconds (GPRS always-on mode) (pleae do not handle these as exact figures, many variables and factors involved).