Why does my desktop very occasionally lag badly when turned on?

[Double Bind]

Hello,

Just a curiosity more than a problem. Sometimes (very rarely) my desktop lags quite badly and shows graphical glitches like it is under intense load shortly after startup, but usually it runs very smooth at all times as you would expect a high end system to perform. Is this just because Windows booted badly if there is such a thing or is it an underlying hardware issue?

Sometimes this happens after I have turned off and turned back on my desktop a few times in the same day. The interval between switching on again after shutdown is at least 20 mins so I don't see why this would be an issue.

 

[Supahos]

Because it can't lag badly when turned off??? (Joke based on title)

Lol no, does I continue until you turn I back off? Or go away in a few mins? Could be updating or checking for updates for some programs