Why do Youtube videos show being completely loaded, but aren't actually loaded?

Question

It's kinda hard to explain. Ever since downloading Firefox 4, I've been getting this odd error in Youtube, and Youtube only. When viewing a video, the time bar or whatever you want to call it shows it's fully loaded, even when just starting to view. Also, when it ends the recommended videos, replay button, Like button, etc, show up a good 3-5 seconds before the video actually ends. This is not an error with Youtube itself. Since I tested it in other browsers. Namely Google Chrome, Opera and even Internet Explorer and didn't experience this problem. What should I do?

Answer 1

It's very difficult to say without knowing more about your system. There are a number of possibilities. First, your 13" lacks a discrete GPU, so the CPU is doing the work that a GPU would have done as far as decoding video streams, etc. Each video stream will consume considerable resources from the machine, and if you have multiple things running with video streams being decoded (for example, a browser with video Flash or cumbersome animation and iMovie running at the same time), then that may be a factor.
Additionally, it could be that you are memory constrained. You didn't post a picture of the process list from activity monitor or the memory usage stats, but you probably want to look and see what the memory and CPU usage is and who's consuming what. Some applications are pretty inefficient. For example, if you have iPhoto open and have thousands of images, the indexed metadata and thumbnails are all stored in RAM. iMovie pulls in clip thumbnail sets - (and worse, it has to do on-the-fly transcoding video assets from some cameras that don't encode the video using the parameters it expects to make indexing frames easier). Again, this would show up as periodic spikes in CPU activity for the app.
You seem to have plenty of disk space, that's not likely to be a problem.
Check if Time Machine is running. Time Machine introduces a performance impact, but it's exacerbated by the presence of frequently changed large files (e.g., you don't want Time Machine backing up your video projects while you are working on them).
Lastly, you may consider checking the console for error messages. This might reveal background processes that might be bogging down the system, or things like filesystem/disk errors. If there are errors in the filesystem, when you access certain portions of the disk, the OS and applications can slow down or lock-up as a result.