You can read this about smr vs cmr which says, among other important things: SMR drives provide random-read functions for rapid data access like their CMR counterparts, but since they require ample idle time or sequential workloads for best performance, they work best with systems customized to take advantage of their high capacity and structure. So SMR drives may be better for backup storage rather than for continuous read/writes. When looking for a HDD, consider $/GB, warranty, brand reputation, etc. Reviews on websites may be slanted toward those with complaints rather than toward those who think the product is good...
Right now I have a XPS 8930 with a 256 SSD and a 2 TB HDD  I am wanting to add a 3 TB HDD to a emptyslot.  I know that I will need a Sata cable as well.  (I watched a video on installing one and it seems like I should be able to to it without a lot of trouble. I have switched out hard drives in older Dell's.)  I was looking at some Seagatehard drives on Amazon and some of the comments said not to get them because they were cmr and not smr. Ormaybe it was the other way around. What I want to do with the new drive is put all my steam and origin games onit So I don't know if it matters whether it is smr or cmr.  I believe I have a Toshiba HDD right now. Any suggestionsof what brand or type HDD I should get?   (I really don't the difference between smr and cmr.) Thanks
XPS 8930, adding 3TB HDD