test server performance

I’m trying to improve my website performance, which are host on an apache VDS.

But even if i’m trying to improve all code, i’m starting to questionning my self about my server.

For example I’m testing a simple very simple image of 3Ko
I get those result:
Load Time First Byte Start Render Visually Complete Speed Index DOM Elements Result (error code) Time Requests Bytes In Time Requests Bytes In
0.302s 0.211s 0.394s 0.400s 400 6 0 0.302s 1 6 KB 0.383s 2 7 KB

is it normal to first byte at 0.211s to view an image of 3Ko?

Sure, when including DNS lookup time and socket connect that is not unreasonable and it will be different depending on where in the world you test from. At a minimum it takes 3 round trips to make a request (DNS, socket connect and then the actual request). From the other side of the globe each of those could take as long as 250ms so 750ms best case. For something close by it can be a lot faster but it is still going to depend on the timing of each component.