To speed up your readings/writings, we have two suggestions. Standard volumes have a default average of 150 IOPS, with a burst capacity up to 450 IOPS. So, we recommend using multiple aggregated volumes, or io1 type volumes instead. Using burst capacity will penalize following IOPS, so for heavy duty usage, either multiple "standard" aggregated volumes or io1 type volumes should be used. The first solution is more complex to put in place but is less expensive, the second one, which leverage SSD, has an additional cost per provisioned IOPS.
For more information, see About Volumes and Improving a Volume Input and Output Performances with Logical Volume Manager (LVM).