Galera cluster slightly slower than single database?
Galera being slower for that benchmark is not surprising.  But is it useful info?
At the end of a transaction, in the COMMIT, the node being written communicates with each other node, asking &quot;will you guarantee that this transaction will succeed?&quot;  (This is slightly weaker, but faster, than actually waiting for the writes to finish on the other nodes.)
What's in the 12 queries that make up a &quot;transaction&quot;?  Does that reflect your usage?
If I munch the numbers correctly, the stand-alone test has 200 transactions running at any moment; 100 for Galera.  Is that realistic?  I hope not -- your quadcore machine will begin to stumble over itself after about 4 transactions.  I would expect it to hit a ceiling long before 200/100 -- This ceiling often characterizes itself by transaction-per-second improving no further, while latency goes through the roof.
Are you hitting all nodes, or just one?
Does a &quot;transaction&quot; have SELECTs in support of the transaction.  I ask this because that is a situation where running transactions on multiple nodes can actually increase throughput.  (On a solo machine, all the selects would have to be done on the Primary.)
Here's an analogy that makes me question benchmarks.  Benchmarks are like testing a hot car -- Drive it for an hour with the accelerator on the floor.  Not realistic.
If you need anywhere near 1768 TPS, neither topology will survive long.