It means that is the type of memory that is compatible with your motherboard.
Buffering and ECC (error correcting code) are features that are mostly used in server systems, and only sometimes supported in desktop systems. So this is just letting you know that you shouldn't get server memory for your desktop system, as it will not work.
You can read more about buffered (aka registered) memory:
and about ECC memory:
Un-Buffered - RAM which doesn't have buffering circuitry. Servers are the only ones which need this as they have a large number of chips on the board.
Non-ECC - RAM which doesn't have error correction capabilities. Only necessary in servers, data centers, and other such applications, not for home users.
DDR3 - DDR3 memory chips.
SDRAM - Pretty much the only kind of memory chips manufactured today you can buy.
can i use this type of un- buffered ram for gaming or should i purchase a standard DDR 3 RAM module since you have stated that the un buffered is mostly used for servers yet am using the cpu for light weight gaming and rendering and home use only ?????
what is likely to happen if i install this type of ram ( un-buffered non-ECC DDR3) module yet i am using the cpu for home use and light weight gaming use and rendering particularly using blender
Standard RAM IS unbuffered non ECC RAM, but there is no way in the universe you will be able to game on that machine, it's built as a cheap office computer. Don't waste your money on a RAM upgrade, it won't do anything.