Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Why does it not show up as a 3TB?  It instead appears to be a 750 GB.
Document: I purchased a 3TB drive based on positive reviews. The box and the product was stamped with 3TB capacity but once it was plugged in, it actually shows up with only 800 GB. Very disappointed. Will return and find another brand that has better quality control.
This is not a cheap HD and it shows. The HD includes all your cables including USB, SATA and Firewire (3ft) and a very nice little carrying bag. It has some kind of stand as.It is very heavy and feel like a quality piece of hardware, it appears to be well designed and designed to hopefully last. I feel safer putting my data on this drive than any other drive I have owned in the past few years. You get what you pay for.
Works well. I run my steam games from this product and I experience virtually no slow down. I would say none but I'm certain someone who is more knowledgeable than me would notice something. To the average consumer, this product should work well. I've only had it a short time though
We've put it to good use in our data center for data transfers. It is fast and functions as advertised.
We have Rocstor Drives involved in a daily back up and data recovery scenario; their overall performance and dependability are outstanding!
This is a perfect external hard drive for saving pictures music and videos. I love that it supports USB 3.0 and eSATA
Not surprisingly I never heard from Rocstor or Amazon as to what the underlying problem was. Based on previous successes I will buy another 3tb Rocstor and write this off as an unfortunate one-off experience.
I'd recommend these. Power supply is built in, which is a big factor for me. Had too many drives with cheap outboard switching supplies appear to drive, when only the $.50 Chinese power brick failed. I have 5 of these working in various functions as so far so good.
I personally contacted some professional well-known photographers to get their advice on some external hard drives and this was what was recommended to me. I have been very satisfied with the speed and solid manufacturing it has. At this point I am using it for video and photo editing running my platforms directly off of it. There is a little bit of lag time at the start up of my editing programs, but in my opinion it is worth it.
I have two 3 tb Rocstor drives and they perform very well and both have been problem free. In April I purchased a third Rocstor drive only to find it would not load and there was a detectable vibration. To the extent it was not operational there was no data loss and essentially no problem except it was dead on arrival. Amazon immediately sent an RMA but at that time there were none in stock so an exchange was not possible although credit was immediately given.
Answer: Just so everyone is clear, the total number of bytes this HDD can store is, in fact, really and truly a full 3 Trillion Bytes. The 2.72 TB you're seeing is simply a different way of counting using 'binary multiples' instead of the 'decimal multiples' we all use in our everyday lives. The operating system typically counts the number of bytes on your hard drive using the 'binary multiples' method, whereas the drive manufacturer uses standard 'decimal multiples'. This is NOT cheating! It's actually a plain language indication of true disk size, rather than using the 'computereez' in use by the operating system... the 'binary multiples' method. In other words, 3TB = 3 Trillion Bytes = 2.72 Trillion 'binary multiple' bytes. They're the exact same thing, only using different number systems to describe them. Stop worrying about getting short-changed... you haven't been! And posting things suggesting you have been simply makes it clear you don't understand computers very well. Go look up the term 'gibibit'  on Wikipedia and read all about it. Pretty soon, you'll be the neighborhood expert! :)