If the laptop had a lot of extra airflow, it may be fine.
I don't think it's an issue of ever leaving the charger. I think it's more an issue of the power being supplied to the computer. The power brick can only produce so much power, and once that is fully depleted, you have problems.
Overclocking is a no-no for laptops.
if you had it set up in a wind tunnel i would still not do it.
Im going to be brutally honest and say its an incredibly stupid thing to do.
When manufacturers make laptops the hardware setup inside is usually extremely fragile due to the manufacturer trying to save money. Some parts are no-name brands and the rest are not made to overclock at all. Any overclock whatsoever would throw off this fragile balance and cause parts to malfunction or function even slower. Plus, the parts in the laptop have almost NO room to breath as they are surrounded by metal and plastic, unlike a desktop machine. And if you know anyone overclocking their laptop they either have millions of dollars to spend, or they are dull.
Even if you had a crazy laptop, the BIOS most likely would not have options for overclocking. Your CPU is also probably locked.
To go even further if one part lets say, the video card fails, hardware is often integrated into the motherboard on laptops, so if your cpu, sound, video, networking, or mainboard fails, you have to replace virtually the entire computer as everything is integrated into the motherboard.
Now I sound a little harsh here, but I know exactly what youre feeling. Your laptop isnt good enough to "keep up" but take my word for it when I say NO because you would rather have a slow laptop than one that does not work.
I hope ppl see this and I hope they read this before overclocking a laptop.
-Blue