How To Install RAM in a PC

This blog post is about how to install RAM in a PC, and also provides details on how I worked out what RAM to buy for a PC I upgraded.


My girlfriend is using an old HP Compaq dx2420 Microtower Business PC, which had 3GB of miss-matched ram installed. We wanted to increase the memory to 4GB.

WARNING! Whilst I hope this blog post helps others, you use the information within this blog post at your own risk! If I’ve made any mistakes and provided any incorrect information, you are not to hold me responsible for any problems, including financial losses.

How I worked out what RAM to buy.

A quick look at the ‘Illustrated Parts & Service Map’ pdf document we have for the PC, and it lists 4GB as the maximum RAM supported and the RAM type as DDR2-SDRAM DIMMS, PC2-6400 (800 MHz) non-ECC. The document also showed a photo of the motherboard with two slots for RAM.

Next I ran CPU-Z (as an administrator) on the PC and looked at the specific RAM in those two slots. It turns out my girlfriend’s PC had been running 2GB DDR2 PC2-6400 and 1GB DDR2-PC2-5300. I noted down the product details for the 2GB memory used in one of the slots. 

DDR2 PC2-6400

A quick search on eBay and I found another 2GB of exactly the same memory which I think would be suitable for the second slot, and a few days later I won the auction and received the used item.

Step 1 – Prepare the computer and yourself!
Whilst it could be tempting to try and install the RAM with the computer left in its usual position, please make sure you place the computer in a clean environment, where you can easily access the motherboard.

All I do is touch a radiator before touching the computer, and make sure the computer is turned off at the wall, but I’m fairly sure I’m taking an unnecessary risk that could result in damage! Worse still I have a wrist strap in a box, that I never use. I don’t think you should take the risk I do!

I’ve read and heard about people using an anti-static wrist strap, connected to the PC case with the power turned off at the wall, with the person stood on an anti-static mat away from carpet, to help try and deal with static which can cause damage.

When you’ve prepared yourself and taken precautions for installing the RAM, remove the side of the computer case that allows you access to view the motherboard and RAM.

Step 2 – Install the RAM and tidy up.
The RAM slots should have plastic clips (arms) at either end which holds the RAM in place. You will need to make sure these have been gently pushed over to the side, and will enable you to place the RAM into the slot(s).

If you need to remove any existing RAM, then you need to gently move the plastic clips either side a stick of RAM to release it, and then gently remove the memory by holding the board, and not the items on the board.

Empty Slot for RAM Stick

The top white plastic clip (arm) in the photo has been moved to the side. Whilst you can’t see it, the same has occurred to the clip on the right of where the RAM will be placed.

Lower the new RAM slowly into an empty slot and make sure you place it the right way round, so that it fits over any plastic in-between the connections, and when satisfied, gently apply pressure on one side then the other so that the arms snap up. Make sure you don’t push too much and damage your motherboard!

One Plastic Clip Pushed Down

The top white plastic clip (arm) in the photo has not snapped up. The bottom left plastic clip on another piece of RAM has locked the memory in place.

If the RAM stick doesn’t appear to be slotting into place, don’t force it and take a moment to assess the situation: Is the RAM type incorrect or the stick the wrong way round? Is the RAM bent or is there an obstruction? Perhaps switch the RAM modules around, and see if that helps.

Once the RAM is in place, do a visual check that everything else seems in order, and when ready place the cover back on the computer.

Memory Stick in a Slot

The RAM is now in place and you can see the plastic arm (clip) on the top-left has locked the RAM in place. You can’t see it, but the same has occurred on the right.

Step 3 – Boot up the computer.
Once you’ve repositioned and connected the computer back up, turn it on and hopefully the new RAM has been recognised and is working properly.

If however, the computer starts beeping, you will need to cut the beeps, which will help you identify the problem.

I had a computer many years ago, where the graphics card worked, but if I did an upgrade to another part of the computer, maintenance or moved the computer, it could cause an issue, with the computer beeping. I then had to reopen, remove and slot the graphics card back into place.

As mentioned towards the beginning of the blog post, the computer I recently upgraded was old, but it still meets requirements. My girlfriend and I are thinking about replacing the old PCIe 2.0 graphics card which has 512MB of DDR3 ram. Another option we’re considering is purchasing a second-hand CPU.


Q. Will I need to perform Windows activation again after installing new RAM?
A. All I can say is that on the Windows 10 free upgrade, I didn’t need to reactivate Windows after performing the upgrade.

Q. Why won’t CPU-Z show the memory slots under SPD?
A. It is likely because you’ve not run CPU-Z as an administrator.

Q. Can I use RAM with different memory sizes and bandwidth in the same PC?
A. Yes you can, but I don’t recommend you do. I could be wrong, but I think faster bandwidth RAM is slowed down to the speed of the slowest. I suggest you use exactly the same RAM in different slots.

Q. How can I view how much RAM my computer uses?
A. I prefer to use CPU-Z, but you could look in your BIOS or via Microsoft Windows OS itself. i.e. On Windows 10, right click on the start icon and select ‘System’ and then a window should open that shows you the amount of RAM installed.

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