I need some more space and since I have already one 500GB drive installed I thought I may as well get another 500GB drive and have 1TBm What do you think , I know I'd save some money but wonder if over all performance will be the same. I've read it somewhere that 2 drives consume more power than say one, do you agree with that ?
Anyways should I buy 1TB drive or should I get 500GB drive and have the same space for less money ?
I would really say it depends on your storage needs. Specifically, do you need only 500 GB more or do you know you would definitely benefit from a full TB extra? Maybe you might even want "room to grow". Anyway, with power consumption, if one drive consumes X amount of power and the other consumes Y amount of power, power consumption would be X+Y, so logically adding another drive would add more power consumption. If you're not super concerned about saving every penny, then I wouldn't worry too much on the cost of it. If you want a recommendation, I'd say it would be best to ask yourself how much space do you know you need, and do you really care about your power savings.
Well, if you want no more than 1 TB, and you want maximum speed and aren't too concerned on data security (such as isolating data on separate drives in the event one fails) you could buy a second 500 GB and take your first one with it and put both in a striped RAID array. In a striped RAID array it will treat both the drives as one giant drive, but as it writes it alternates between the drives, nearly doubling your speed. However, if one drive fails, you will lose the data on both since for each given piece of data each drive stores half of it. However, if you had just a single 1 TB drive you will still lose all your data in the event of a drive failure, but being it's a single drive you won't have the speed of a striped RAID array.
So if you get a 1TB drive, the only main benefit over two 500 GBs is the power consumption of a single drive (which in my opinion is marginal to begin with, but I respect the fact that there are power users out there that need to save every watt possible). If you get a second 500 GB, you have options with how to manage them, either keeping them separate in the event of data loss, or combining them in a RAID array for increased speed. If suppose then I would recommend a second 500 GB, especially since you don't want more than one TB, and a 500 GB is cheaper than a 1 TB drive.