DDR3 RAM sticks, all of them. The ones above are 4GB, but I don't know their speed. As for the ones below, they are all 8GB with a speed of 1600Hz, and they are considered good. If you buy both of the ones below, a feature called dual-channel will be activated, which allows the processor to send data to the RAM quickly. The ones above are priced at 40. The ones below are priced at 80. If you buy both, there's a different price.