The space of value systems is vast, but I don't think the particular subspace of value systems that attempt to maximize some simple pattern (such as paperclips) is large enough in terms of probabilistic likelihood mass to even warrant discussion. And even if it was, even simple maximizers will first ride Moore's Law if they have a long planning horizon.

The space of expansionist replicator-type value systems (intelligences which value replicating entire entity patterns similar to themselves or some component self-patterns) is a large, high likelihood cut of design space.

The goal of a replicator is to make more of itself. A rational replicator will pursue the replication path that has the highest expected exponential rate of replication for the cost, which we can analyze in economic terms.

If you actually analyze the cost of interstellar replication, it is vastly many orders of magnitude more expensive and less efficient than replicating by doubling the efficiency of your matter encoding. You can double your population/intelligence/whatever by becoming smaller, quicker and more efficient through riding Moore's Law, and the growth rate of that strategy is vastly orders of magnitude higher than the rate of return provided by interstellar travel.

This blog post discusses some of the cost estimates of interstellar travel.

Interstellar travel only makes sense when it is the best investment option to maximize replication rate of return. Consider that long before interstellar replication is economical interplanetary expansion to the moon and mars would be exploited first. And long long before that actually becomes a wise investment, replicators will first expand to Antarctica. So why is Antarctica not colonized?

Expanding to utilize most of Earth's mass is only rational to replicators when Moore's Law type growth stalls completely. So hypothesizing that interstellar travel is viable is equivalent to making a long term bet about what will happen at the end of Moore's Law.

What if Moore's Law type inward exponential expansion has no limit? There doesn't appear to be any real hard limit on the energy cost of computation.

A molecular level civilization could be mind boggling vast and fast itself, without even considering reversible computing and then quantum computing. Much also depends on a final unified theory of physics. There is speculation that it may be possible to re-engineer space-time itself at the fundamental level - create new universes, wormholes, etc. All of this would open possibilities that make space travel look like the antiquated dreams of small-minded bacterium.

I think it's extremely premature to rule out all of these options and assume that future super-intelligences will suddenly hit some ultimate barrier and be forced to expand outward at a terrible snail's pace. It's a failure of imagination.