For Basically a professional/server version of the TITAN 5GB of memory seems strange. Since Titan has 6GB of memory and the 780TI has 3GB I though it would be increased in 1.5GB size intervals.
Maybe since enabling ECC will cause some of the memory to be used for the ECC bits, so the user available memory will decrease by 10%, they threw a little extra on.
I could be way off since i just opened my eyes and had only a sip of coffee so feel free to correct me.
Desktop ecc adds another chip as that's how their memory bus has been designed. Basically everyone not using ecc has extra dimm traces and logic sitting unused because its been decided that its "ok" to use data integrity as a market segmentation feature as dram density has increased 1000 fold in a decade or so. The whole situation is **** dumb, plain jane desktops still manage tons of data all over the world and they should have gone 9 dram chips standard ages ago. A lot of data buses already have ecc or similar functions running on them because errors do happen period, its nature.
Except for crap like older atoms and more recently some amd apus, every single amd and intel wafer for many years supports ecc when it comes out of the fab. It might be disabled later depending how it is binned. For an example of this stupidity, desktop i3s support ecc as they are sold along with E3 xeons by many server vendors as the bottom tier dual core option, however i5/7 do not. They also make very
sure no unlocked cpu supports ecc, though ironically if you don't care about overclocking many E3 xeons can be cheaper than identical speed i5/7s.
A lot of GPUs instead reallocate through their memory controller to accomplish the same algorithm, I believe that titan has 6GB physical.
Tune in next week for my rant on why all hard drives are trash and your file system is a joke even if you don't know it: just remember 2 is one, 1 is none.