See this comment about throttled SLC 5/05 traffic, the 5/04 has similar throttles:
If those aren't your problem, then you should check if you are running your DH+ at 230k. If not, you can get a 4x improvement by converting (all devices on the channel must be capable of this, and be configured together).
Other than that, no. You'll just have to go slower. (Tag group rate.) You can only fit so much [expletive] in a one-pound bag. (The normal euphemism is ten pounds in a five-pound bag, but DH+ is a much smaller "bag".)