Have you thought about scaling back your server a bit to reduce the costs? a 32 GB RAM server, or even a 16 GB should be enough if you are storing the memory file on SSD.
More details here:
https://steemit.com/steem/@steemitblog/exploring-steem-scalability
yeah... I am even looking into using zram to reduce the cost. Thanks @timcliff for the advice.