I assume you are using a Pentium M or a Core (2) Duo. If so, the 1.73Ghz is comparable to a 2.6Ghz Pentium 4.

Ghz ratios are a bit misleading these days. I remember some guy thinking that a 1.86Ghz Core 2 Duo E6320 could not run H2V (2.00Ghz P4 requirement), just because it said 1.86 Ghz, when in reality the 1.86Ghz kills even a 3.8Ghz P4.