Why is a download manager required to utilize full download speed available via isp from computer in california accessing ec2 instance in virginia?

So far I get an average of 700 kilobytes per second for downloads via chrome hitting an ec2 instance in virginia (us-east region). If I download directly from s3 in virginia (us-east region) I get 2 megabytes per second.

I've simplified this way down to simply running apache and reading a file from a mounted ebs volume. Less than one percent of the time I've seen the download hit around 1,800 kilobytes per second.

I also tried nginx, no difference. I also tried running a large instance with 7GB of Ram. I tried allocating 6GB of ram to the jvm and running tomcat, streaming the files in memory from s3 to avoid the disk. I tried enabling sendfile in apache. None of this helps.

When I run from apache reading from the file system, and use a download manager such as downthemall, I always get 2 megabytes per second when downloading from an ec2 instance in virginia (us-east region). It's as if my apache is configu开发者_StackOverflow社区red to only allow 700 megabytes per thread. I don't see any configuration options relating to this though.

What am I missing here? I also benchmarked dropbox downloads as they use ec2 as well, and I noticed I get roughly 700 kilobytes per second there too, which is way slow as well. I imagine they must host their ec2 instances in virginia / us-east region as well based in the speed. If I use a download manager to download files from dropbox I get 2 megabytes a second as well.

Is this just the case with tcp, where if you are far away from the server you have to split transfers into chunks and download them in parrallel to saturate your network connection?

I think your last sentence is right: your 700mbps is probably a limitation of a given tcp connection ... maybe a throttle imposed by EC2, or perhaps your ISP, or the browser, or a router along the way -- dunno. Download managers likely split the request over multiple connections (I think this is called "multi-source"), gluing things together in the right order after they arrive. Whether this is the case depends on the software you're using, of course.