Reply To: Before you purchase, just know that some of these questions could be better..

[Lifelong1250]

<div>OK Jon, that is fair. I want to stress that with a few exceptions, I think the questions are great. I haven’t certified in a few years so they are helping me find my weak spots. I am glad you’re responding to the post and I am going to start posting questions here so we can discuss.</div>

Question:

A company deployed a high-performance computing (HPC) cluster that spans multiple EC2 instances across multiple Availability Zones and processes various wind simulation models. Currently, the Solutions Architect is experiencing a slowdown in their applications and upon further investigation, it was discovered that it was due to latency issues.

Which is the MOST suitable solution that the Solutions Architect should implement to provide low-latency network performance necessary for tightly-coupled node-to-node communication of the HPC cluster?

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The correct answer is :
Set up a cluster placement group within a single Availability Zone in the same AWS Region.
(that is what I selected)

But I have a question about this answer:
Use EC2 Dedicated Instances with elastic inference accelerator

Now, I know that EIA doesn’t have any impact on the solution. However, in the explanation you state:
Use EC2 Dedicated Instances with elastic inference accelerator is incorrect because these are EC2 instances that run in a VPC on hardware that is dedicated to a single customer and are physically isolated at the host hardware level from instances that belong to other AWS accounts.

My question: Ignoring the EIA, wouldn’t instances on the same physical hardware provide for the lowest possible latency?