Aura instances come predefined with resources allocated for memory (RAM), storage (disk) and processing capacity (CPU) and have been carefully tuned and configured to perform well.
If you find that you may need more memory or more CPU or storage to meet the needs of your application workload then you will need to align the resource need to the standard offering.
AuraDB Professional does not allow for customisation of resources.
Similar to the Professional Tier, the Enterprise Tier has standard sizing; however, you may contact the Neo4j Aura team to discuss any special requirements you may have.
See the full instance sizes details here: https://aura.support.neo4j.com/hc/en-us/articles/360053015393-What-are-the-Aura-instance-sizes-available-per-subscription-tier-Professional-Enterprise-
Pricing details: https://neo4j.com/cloud/aura/pricing/