快速传输特定文件（大小> 70MB）到两个不同区域的S3桶？

I want to transfer a file whose size is greater than 70Mbs into two S3 buckets ( 1 - Our S3 bucket in same region and 2 - Client's S3 bucket in different region) of different region with minimum transfer time.

Following are the steps which I have implemented for the above requirement but it is taken too much time to transfer file specially in client's S3 bucket

1. I have created two objects of S3 AWS, One with our access id and access key and another is with client's access id and access key.
2. First I use our S3 AWS object to transfer file into our S3 bucket which is in same region through PUT Object function and it is not taking much time.
3. Then I use client's S3 AWS object to transfer file into client's S3 bucket which is in different region through PUT Object function and it is taking too much time.

I have also tried an alternate way to do the same is - first transfer file into our S3 bucket then transfer that file from our bucket to client's bucket through COPY Object function, but i found this process is also taking too much time.

So please help me out on this. I want to reduce the time taken to transfer the file into S3 bucket which is in different region. And Yes I forget to mention that I am using PHP as a client so please provide solution in php.

Thank in advance, Any help or suggestion would be appreciated.