When it comes to fine-tuning Network and Storage performance of Virtual Machines here are some things to consider
Networking (Bandwidth)
- Accelerated Networking reduces network latency, improves throughput, and decrease CPU utilization of a Virtual Machines. If you need above deploy select supported Virtual Machine SKUs always enable this feature.
- The bandwidth limit is cumulative of all outbound traffic from the virtual machine across all attached Network Interface Cards (see here). So, for example, if you use Standard_D1_v2 Virtual Machine SKU you can have a max of 700 Mbps and for Standard_D2_v2 its 1500 Mbps

Storage (IOPS / Throughput)
- Every Azure Managed Disk size has Max IOPS and Max Throughput (see here)
- Every VM has a limit on how much throughput and IOPS it can provide (see example)
- So, the overall throughput / IOPS you can get is capped by min of (VM, Managed Disk)
Also, Consider
- You can optimise disk Read IOPS by enabling caching, improve performance by implementing Striped Volume etc. (See here)
- Ultra-disks allow you to choose desired IOPS/Throughput (max IOPS: 160,000 and Max Throughput: 2,000)
- If you wish to benchmark your disk performance, consider IOMeter tests
Finally
- If you are using Azure Files or NetApp files remember they use Network Bandwidth vs IOPS so choose a SKU that optimises Network performance.