What are the factors to a high AUDIO track count?

Say you have 50 tracks, 48Khz/24-bit. What are the factors to make sure those 50 tracks play perfectly without a single glitch? Hard drive is obviously the most important thing, but it seems no one talks about HDDs anymore. Its all 7200 rpm and the capacity is a non-issue. So when it comes to a daw, what makes the DAW powerful as a sample-heavy+ audio-heavy capable DAW?

Not sure if you noticed this link posted in your other thread? It's all about high track counts and disk. Also, if the question truly is high track counts and disk, you'll want to see what that limit is before including anything else such as VSTs etc. It doesn't matter if you'll use them later, you need a baseline that includes only audio and disk performance first so you'll know where your starting point is. ;) Ultimately, there is a point where more than just the disk matters because the processor has to process all the audio coming from those disks so there is a line where those two (proc/disk) affect each other.

Track count without plugins is pretty much an HDD thing. Its probably a good practice to only pull about 48 full tracks of each 7200 rpm drive. If you do a lot of samples from a library in addition to the audio track... That should be in its own drive This is how my main rig is. System Samples Audio 1 (first 48) Audio 2 (second 48) Storage