Does the size of RAM affect speed of computer? If yes, how?

Answer by Prasannjeet Singh:

Well, in some cases it does and in some, it does NOT affect the speed of the computer.

Let me explain this metaphorically: (I think Indian readers will understand this better!)

There is a street food in India called as Pani-Puri (also Golgappa).

​Little about this street food (Skip this para and the next if you already know about it!): Immediately after the request, vendor hands us a plate (size of the plate varies from place to place). After everyone around him has a plate in their hand, he starts making Pani-Puris, ONE at a time (doesn't matter what actually is in Pani-Puri) and putting one each in everyone's plate, either clockwise or anti-clockwise, and it goes on until I reach my limit.

Now, my objective as a customer is to finish my Pani-Puri before the vendor serves everyone and comes back to serve me (because the plate generally can't hold more than one Pani-Puri), no matter how spicy, or hot I feel. Because if I don't, vendor will skip me and I will have to wait one whole round to get my piece of Pani-Puri. By the way, it only takes 3-4 seconds per serving, so your chance to eat the next one come pretty fast! Also vendors are happy to wait if you are the lone customer. Sometimes, the vendor waits for you which upsets the other customers!

Now consider the plate given to you as the RAM:

​And your mouth as the Processor.

Similarity: Just like the customer picks Pani-Puri from the plate before eating, the processor picks up data/instructions from the RAM before processing.

Now let us consider few very simple cases:
Case 1 – Small plate but fast customer: If the plate is really small and only one Pani-Puri can be there at a time but you are fast enough, you can easily finish the current Pani-Puri and safely wait for the new one. Maybe you can eat something else in the meantime.

Similarly, if you have low RAM but extremely fast processor, your processor can blisteringly process all the instructions stored in the RAM thereby constantly emptying space in the RAM for more and more instructions to come.

Case 2 – Small plate and average customer: Consider you have the same plate as above but you are a slow eater, there will be a time when the whole system comes to a halt when there is one Pani-Puri in your plate, one in your hand waiting to go in but you are already eating one, also the vendor is ready with another one in his hand waiting to put it in the plate as soon as you empty it!

Similarly, if you have a rather small RAM and an average processor, your system may start hanging because your RAM is full with new instructions, but the processor is processing previous instructions and there are new instructions waiting to go in the RAM as soon as it had some space.

The reason your computer becomes slow in this case is because your computer is a multi-tasker and it has to process most of the instructions at the same time. But as discussed, few of the instructions are not even in the RAM so the processor tries to accommodate all of the instructions inside the RAM by switching instructions back and forth from RAM to the Hard Disk and vice-versa. This process which involves the hard disk is unimaginably slow, thus making your system slow.

Case 3 – Big plate and average customer: Now if you are not fast enough to finish one Pani-Puri before the vendor is ready to put one more down there, it is really handy if you have a little bigger plate! This way the vendor continues to add more and more Pani-Puris to your plate and you keep eating them at your own pace. Everyone is happy!

Similarly, if you have an average processor but a little better RAM, the processor can process each instructions in it's own speed while still receiving next instructions safely in the RAM (because of is large size) which the processor will process as soon as it is free from previous instructions.

Case 4 – Average eater but very big plate: Consider that your plate can accommodate 10 Pani-Puris at a time and your friend standing beside you has another plate which can somehow have 15 of them at once, and one serving of Pani-Puri has only 8 pieces. Assuming both of you are average eaters and slower than the vendor, Pani-Puris will keep stacking up in both your plates. Now your friend has a bigger plate than you but will it actually make any difference? No. Because obviously maximum number of Pani-Puris any of you can get is 8 and both your plates are capable of holding that much. Anything above that will just make no difference!

Got the hang of it? I think you can figure out the similarity!

Therefore, we can conclude that higher RAM does speed up the computer (Case 3), but not always (Case 4).

Thank You!

Note: The concepts are not perfectly correct as many more steps are involved before the processor can actually process an instruction, such as the use of cache memory, etc, but these can be safely assumed to understand this particular argument.


Does the size of RAM affect speed of computer? If yes, how?