what does this mean???

TLDR: If your processor is 64 bits (aka, within last 8 years) and your OS is 64 bits (within last 8 years) this is not a problem you need to concern yourself with. It won't crop up for you.The brief explanation of what this problem is, when you run a 32x processor or OS: Every byte on a RAM stick needs a unique number identifier. 32 bits (the maximum address size of a 32x processor or Operating System) only allows a number big enough to reach ~4GB of RAM. If your processor is 64 bits, and your Operating system is 64 bits, this warning has no bearing on your situation.

Simplified technical explanation, if you want to know why.

When you refer to bits in a processor (or Operating system... the bits of an OS is just a reflection of the processor it's supposed to run on), it's how much data a single element can be (these elements are known as "words").

32 bit means a word can be 32 bits. Newer 64 bit processors mean they can be 64 bits.

How this is relevant here:

To use a very simple example, let's say we have 16 bytes (16*8 = 128 bits) of RAM. The byte is the smallest unit of change in RAM. You still have to count every bit though, when giving these addresses out, however, the system of storage works based on the starting position of a bit (the first bit in the byte).

Say our processor uses 2-bit words, what's the highest possible value we can have as an address?
10 -> 4 (values have to be word-aligned, meaning a multiple of the word size)

Byte 1 (bits 0-3) and byte 2 (bits 4-7). So you're unable to address 14 bytes of the additional space as you have no way of referring to it.

Now, pretend we use a 4 bit processor.
Highest value?
1100 -> 12. (byte 1[bits 0-3], byte 2 [bits 4-7], byte 3 [bits 8-11], byte 4 [bits 12-15]). Better. Now you can address 4 bytes of 16.

Ultimately, to address a full 16 bytes of memory, you would need 16*8 = 128 bits.... -> a processor with a word size of 7 (2^7 = 128).

Your issue here is the exact same problem, just with much bigger numbers. As it happens, the highest possible value you can get out of 32 bits (2^32 -1) is just about enough to address 4096 bytes (4GiB of RAM).

If you got a 64 bit processor, you could address TiBs of RAM. It grows very quickly.

Note: I talk about the actual processor here; however, functionally a different-bit operating system is the same limitation, as it understands things the same way.

The OS being 32x or 64x is just a reflection of the processor it expects to work on. Can't stick 64x through a 32x opening, but you can run 32x on 64x because it's half the word size.

I took a university class specifically on processor architecture, so sorry if this is more than you wanted to know, but I wanted to tell someone and it's relevant! Yay!