[NAME] , The supported configurations meant they were tested with optimal performance for your system.  Scalable storage up to 8TB seems plenty enough.  You can add higher capacity drives, not supported doesn't mean that it won't work.
Hi, I just bought today a new Dell Precision 3440 SFF Desktop Core i7-10700 16GB RAM 512GB SSD. Since I will be storing lots of personal pictures and videos, 512GB will not be enough and I'm planning on buying additional storage, most likely internal. So I browsed the 'Setup and specifications guide' and the Storage chapter contains a list of the supported configurations and apparently I cannot freely add storage according to my needs! For example, according to a table on the referred chapter, the maximum storage capacity is 4 TB (3.5" HDD drive with 5400 rpm). Does this mean I cannot buy an HDD with a capacity of 5 or 6 TB? Also, one of the supported configurations described in the chapter is: "One M.2 2230 or 2280 solid-state drive (class 40)". Can't I have both a 2230 and a 2280 M.2 SSD? There are 2 slots available and one is free. Are these combinations really mandatory? Or am I getting this all wrong and these are the different storage configurations available for purchase in stores for the Dell Precision 3440 SFF model? Below is the excerpt from the manual. Thanks for any help! Regards, Nuno Guerreiro   ----- excerpt from the manual, page 15 ----------------------------- Storage Your computer supports one of the following configurations • One 2.5-inch hard-disk drive• Two 2.5-inch hard-disk drives• One 3.5-inch hard-disk drive• One 2.5-inch hard-disk drive and one 3.5-inch hard-disk drive• One M.2 2230 or 2280 solid-state drive (class 40)• One M.2 2230 or 2280 solid-state drive (class 40) and one 3.5-inch hard-disk drive• One M.2 2230 or 2280 solid-state drive (class 40) and one 2.5-inch hard-disk drive• One M.2 2230 or 2280 solid-state drive (class 40) and two 2.5-inch hard-disk drives Table 6. Storage specifications  
Dell Precision 3440 Small Form Factor storage configurations