I have worked as a student immigration adviser for 25 years, and interestingly it is only ever students from the US who ask about options for coming to the UK before their student visa starts.
The one month lead-in period is specifically designed to allow some flexibility for travel, and to allow some time for finding housing.
While it is technically possible to come to the UK as a General Visitor before the Tier 4 visa kicks in, as advised above it is logistically, financially and legally awkward. The Border Force Officer would need to be satisfied that you are a genuine visitor, coming to the UK for a short visit and leaving again within 6 months, with no intention to study during your visit. You would then need to leave the UK, and re-enter under your Tier 4 visa in order to start your studies. You would need to be very clear and mindful of the fact that you were presenting yourself in two totally different immigration categories, each one with its own rules, conditions and requirements.