What is the most server intensive feature in Dolph

It seems yet another 'speed' based forum post!...

What is the most intensive requirement/feature on Dolphin for bandwidth and speed on the server... Or, what is the most likely to sloooow things down.

I have a new site launching, it has some videos but not many that stream from the Dolphin server, and active forum. Other than that, its pretty minimal. Has some embeded features within articles but then I guess as they are embeded they use their own servers bandwidth?

IF I use video embeds from youtube rather than self hosted, are they not going to use my bandwidth? This would be the main feature I can think of on my site other than forum that would use bandwidth. If I can lighten this I guess it would really help with longterm site running?

So, main question other than what Dolphin features are bandwidth intensive is, do video embeds from another site not effect your own bandwidth or am I getting it wrong in my thinking!?

I suppose it'd be the audio/video communications available (chat, messenger...), but that's only an issue if your RMS plan has a limited amount of resources available to it. Personally, I believe it's the video uploading which can drain your bandwidth if enough people use it. Since embedded video is hosted on a remote site, you shouldn't be taking a hit from it bandwidth-wise.

as I thought.

So if I want to reduce bandwidth and speed up my site, it would be beneficial to have the script on a server, then to have all vids as embeds on say youtube, then any file downloads just as links to another server. That way the only thing on the main bandwidth is the script running.

Would this significantly speed up the site though or at least prevent it from slowing down!