If the serialization is really the bottleneck, as you say, then you aren't serializing the data in the Isar evaluation. Which makes the comparison unfair.
Your comment reads a bit like saying you don't like a Toyota car for transporting apples, because it takes too long to bake a pie out of them first.
BTW, if Isar's data format really is "very close to in-memory representation", then why aren't you simply packing the 512 floats into an array (which I guess is how this data is represented anyhow), and use this continuous block of memory directly as the serialized value?
Your comment reads a bit like saying you don't like a Toyota car for transporting apples, because it takes too long to bake a pie out of them first.
BTW, if Isar's data format really is "very close to in-memory representation", then why aren't you simply packing the 512 floats into an array (which I guess is how this data is represented anyhow), and use this continuous block of memory directly as the serialized value?