My sweet husband got to hear how much I didn't like his very expensive mattress. No matter the "number" this bed was uncomfortable to me. I got this memory foam mattress topper to see if it would help (a lot of the decision was based on the reviews) and it helped so, so much! For 200.00 saved us from getting a new mattress for the time being. Not hot, really comfortable. Good fit to the California king bed.