This is not true, and the lowest limit of sleep you can get and still feel normal, energized and restarted is 6 hours. I've been testing trough the years and I've been sleeping 3 hours during the day, and 3 hours during the night and I felt more energized than sleeping full 8 hours trough the night. This is because during the day you are stressing the body and brain with the full 15-16 hours of activity, so you need to make a balance with short sleeps. It is also very good if you sleep 4 hours during the day and 4 hours during the night. Your body will feel much more energized as there will be a time balance in spending energy and renewing energy. Productivity levels will certainly increase 20-30% as your brain will be prepared for all sorts of tasks.
The most important part of quality sleep is getting into rem. People find this very hard to control and can't get into rem immediately after going to bed. but over time while watching some videos about hypnosis I found out that when you go to sleep, if you start breathing very slow and deep, and stop thinking about anything and just go into a complete darkness (I imagine space) you go into rem almost 90% of the time and you will be getting high quality sleep.
You will find it hard at the beginning to stop thinking about anything but after a week or two you will get used to it and you will find how easy it is to fall into deep sleep.
And spending too much time in front of the pc is definitely bad for your sleep. Be very careful to spend your time effective and productive.
Exercises and stretches before going to sleep will also allow you to go into deep sleep fast and wake up easier, full of energy.