AWS EFS Throughput not exceeding 1MB

I hope you can assist with a question around EFS throughput that I am seeing on our AWS services.

I have setup an EFS filesystem which I have mounted on 2 x EC2 instances. Originally, I had it configured as burstable throughput.

When looking at the MeteredIOBytes metric, the maximum throughput never exceeds 1.05M. I thought it might be because I am not using much space on EFS and as I understand it, when on burstable throughput, the throughput increases as you use more GBs.

I then tried changing the EFS to provisioned throughput of 5MB, but even after doing this, the MeteredIOBytes metric never exceeds 1.5MB.

efs1

In both burstable and provisioned mode, when comparing the maximum MeteredIOBytes with PermittedThroughput, the MeteredIOBytes is way below Permitted.

efs2

I am only using 3GB of storage space on EFS.

Is there a setting I am missing to increase the throughput beyond 1.5MB?

Thanks