Overclock the processor
Overclocking is the ultimate upgrade if you want more speed and can be performed without disassembling your netbook. It's also one of the more dangerous upgrades, given that these netbooks don't have the best cooling systems.
Your netbook could crash or freeze if you raise the speed or temperature too high, too fast. In many cases, overclocking will void your warranty, too.
For the brave, then, we've listed a number of applications that can help.
Abo's free, open-source SetFSB tool lets you tune the speed of your CPU, memory and key controllers on virtually any Intel Atom-powered netbook.
Asus Eee PCs can be overclocked to run 10 percent faster (or 30 percent in the case of the Eee PC 1101HA) using the preinstalled Super Hybrid Engine preinstalled. If you hunger for yet more speed, turn to Eeectl.
This free two-year-old app from Russian developer DCI lets you control the speed of the motherboard's front-side bus as well as the CPU voltage - the two virtual knobs you need to twiddle to over-/underclock your CPU. The ever-handy Eeectl also lets you double your screen's brightness, control the fan and configure various hotkeys.
It works on older 700-series Eee PCs with no need for modification. For other Eee PC machines, you may find you need to modify the code.
Finally, any netbooks that use the Intel GMA 950 graphics chip that's integrated with the motherboard of most Atom-based laptops - that includes the Acer Aspire One, most Asus netbooks, Dell Inspiron Minis, MSI's Wind, all the HP Minis except for the 2133 and Samsung's NC10 - can make use of GMABooster.
This handy application can boost your netbook's graphics chip from 133/166MHz to 400MHz without increasing the voltage.
GMABooster is easy to use, but it isn't without its hassles. To use the app for free you must download and install a new version each week. By making a donation you can avoid this annoyance.
Replace the battery
Probably one of the easiest ways to upgrade your netbook is to replace the battery. Most netbooks come with a three-cell battery, but replacing this with a six-cell version will extend life considerably.
You may find advice online that suggests creating a larger pack by wiring together a number of aftermarket batteries. But this is a recipe for disaster. Instead, check eBay: here, we managed to pick up a larger-capacity battery compatible with the existing connections (and size) of our Dell Inspiron Mini 9.
To replace the battery, flip over your netbook and look for two switches marked with lock and unlock icons. Slide both to the unlocked position, then slide out your old battery. Insert the new battery and lock it into place.
You'll almost certainly find that the battery won't lie flush with your netbook, so only attempt this upgrade if you don't mind a lump sticking out the rear.