On linux i can mount a partition in memory (Install ubuntu/debian)

sudo mkdir /mnt/ram
sudo mount -t ramfs -o size=200G ramfs /mnt/ram
mount to show you the partitions mounted

and then move your database into the ram partition

http://aws.typepad.com/aws/2013/01/ec2-for-in-memory-computing-the-high-memory-cluster-eight-extra-large.html

That large instance could help you with the Firebird cache settings also the extra SSD could do wonders

Inspired by the stack overflow big fat server architecture

http://highscalability.com/blog/2009/8/5/stack-overflow-architecture.html