Increasing the memory can improve the performance of most computers, even older systems like Compaq that use Intel's Celeron 1.4 GHz. By expanding the memory in your Compaq, you can easily run a number of low resource operating systems like certain Linux distributions.

Memory Limits

Most Compaq computers old enough to have used a Celeron 1.4 GHz have a limit of 512 MB of RAM. Many computers came standard with 128 MB of RAM. Increasing your memory to the maximum will improve performance and help keep an older computer working a bit longer.

Memory Type

Most Compaq computers that used the Celeron 1.4 GHz processor use PC133 Dual Inline Memory Module (DIMM) RAM, which hasn't been made for some time. However, a number of online sources offer leftover stocks of this memory at very reasonable prices. To upgrade the memory in your computer, you must first remove the old DIMMs and replace them with higher capacity memory modules.

Removing Existing Memory

The fist step to upgrading the memory in your Compaq is to remove the old memory. Depending on the Compaq model, once you open the case and locate the memory modules, you may need to either press down on the plastic tabs on either side of the DIMMs to raise them out of their sockets, or un-clip the sides and swing the DIMMs outward to release them from the sockets. Look for one or two 5.25-inch long boards at a 90-degree angle to your main board with either plastic or metal clips on either end.

Installing the New RAM

Insert the new DIMMs into the sockets. If you pulled straight up on the old DIMMs to remove them, press the new ones in place. If you swung the old DIMMs outward, place the new DIMMs in at an angle and swing them upward to lock them in place. Look at the notch on the bottom of the DIMMs and match it to the protrusion in the memory socket.

Source:

Memory Stock: RAM Upgrades For Compaq Presario 6300 US Computer