Not sure to understand you, did you mean faster blockchain at 128kb
What I mean is -- when you broadcast a transaction with 128KiB of data within it you will want the TX distributed through the network so it can easily be included by miners in the next block.
A limit of 128KiB makes it possible for even the most limited peers to be able to verify and relay the transaction in a relatively short period of time.
big file are writen on multi TX ?
The "how to" is up to you. Think of it like splitting a file into multiple chunks where part 1of8 is in one transaction and part 2of8 is in another transaction.
In this way you are able to spread a large upload across multiple transactions.
If you're familiar with Usenet and the alt.binaries newsgroups, it would be similar to seeing a nice large upload split across dozens of posts.
Best Regards,
-Chicago