There's an advanced property on the realtime tag providers (in the gateway Config > Tags > Realtime) called "Memory Resident Tag Properties" since ~7.9.1. You could try enabling this. As you can imagine given the name, there's a tradeoff in that it uses more memory.
Other than that... reduce your dependency on browseTags. Call it less often, don't call it at high levels in the tag structure where it has to do a lot of recursion, cache results when applicable, hard code lists of tags instead of relying on tricky dynamic generation.