Bests & Worsts Reviews from Amazon

I purchased 10 4tb drives from amazon and they are being used in a RAID 6 with an Areca raid card. The features that make this drive great for a NAS also make it great for a normal RAID. Out of the 10 drives I purchased, none were DOA! The packaging was great from amazon as always. If you buy your drives from a different supplier, good luck! One thing Seagate seems to be trying to hide is the fact that the 4tb model's spindle speed is only 5900RPM, but don't think too much of this. For a NAS, it really doesn't matter one bit because the limiting factor for speed is normally your method of downloading data off the NAS (AKA, an ethernet 10/100/1000 port only goes up to 120MB/s). For a regular raid, it will impact performance a bit. Read/write benchmarks from HDTune Pro: Read: Min: 79MB/s; Max: 175 MB/s; Average: 140MB/s; Write: Min: 74MB/s; Max: 172 MB/s; Average: 135MB/s; Access Time: 17.3ms The drives are running at between 32 degrees celsius and 45 degrees celsius in my case after being under full load for the past 10 hours. It's completely dependent on how much airflow you have on your drives. Q&A section: What is a NAS? NAS = Network Attached Storage. Basically, it's a box of hard drives that you can access over your network or use as any external hard drive via USB/eSATA. What makes a NAS different than a normal external drive is a few things. The main reason is because you can normally setup a RAID on a NAS so if a hard drive dies on you, you don't lose a single bit of data! Different raid versions offer different levels of redundancy. If you have a RAID with redundancy setup and a drive dies, all you need to do is buy another drive of the same make/model/(and hopefully firmware version), put it in the NAS, and you can rebuild that hard drive's data based off of the data on the other drives in your NAS. The amount of data redundancy is completely up to you. You're the one buying the NAS and picking what type of RAID you want in it. Most NAS's support Raid 0 (no redundancy), 1(drives are mirrored), and 5(contains 1 drive worth of parity data so you can lose any 1 drive without data loss). If you need more information on RAID types check wikipedia:[...]RAID or reply to my review with your question. The other advantage of having a NAS over a normal external is that limitless people on your network can use it at the same time. Why is this drive better for a NAS or a normal RAID? A NAS drive is better built drive with more advance firmware. It's essentially a cross between a desktop hard drive and an enterprise hard drive for the home user. 1) NAS drives are designed to be online 24/7 where as desktop hard drives are only supposed to be on for a fraction of that time. Your NAS will be online 24/7. 2) NAS drives are more tolerant of vibrations 3) NAS drives use less energy (aka, doesn't get as hot). Seeing as your drives will be in a little box with poor airflow, this is a very good thing. 4) A NAS drive's firmware has more has some enterprise drive features. Seagate calls this "NASWorks". 4a) The main reason you want the better firmware for a NAS or any raid for that matter is because it supports TLER (time limited error recovery). This limits the time the hard drive can take to try and recover data to 7 seconds where as a desktop drive could take much longer. When this happened to me on a RAID of drives without TLER, the entire raid hung for 20-30 seconds. It would normally recover, but it eventually kicked the problem hard drive out of the raid. If that drive had TLER/NASWorks, the hard drive would have attempted to get that data for a max of 7 seconds before asking the raid controller for help. The raid controller would know that chunk of data is on other hard drives as well and so it can attempt to rebuild the problem section. Instead of the drive being kicked out of the raid, it would have recovered on its own and a full drive rebuild could have been completely avoided. Why not use enterprise drives instead? This comes down to the money. An enterprise drive will likely run you twice as much money as a NAS drive and most people wouldn't even see much of a gain from it. Enterprise drives are built for extremely heavy use. If you are running virtual machines, hosting websites, and/or constantly using your NAS, enterprise drives might be worth the money. For the bulk of us just using a NAS for a file share, it really isn't needed. Even if a few NAS drives end up failing down the road, replacing them would be cheaper than if you originally bought all enterprise drives. Why a 5 bay limit? I sent Seagate an email about this one because I couldn't find any information about it online. They said it was mainly because most NAS systems wouldn't support multiple backup drives. You really wouldn't want to use a RAID 5 (lets you lose any 1 drive and recover) with more than 5 2-4tb drives because of the amount of read/write cycles that happen when you have to rebuild a hard drive. You have a much higher chance of a second drive failing during a rebuild. Basically, go beyond the 5 bay limit at your own risk. If your NAS or raid controller supports RAID 6(lets you lose any two drives and recover) or RAID 10 (stripped and mirrored) AND YOU USE ONE OF THESE ARRAY TYPES, the 5-bay limit can be ignored. Seagate tech's exact words: "There shouldn't be any limitation that prevents you to use more while attached to a regular [raid] controller in a different type of raid." Will this work in my old external enclosure? Chances are it won't, but to be sure you'll have to check its spec. A lot of external enclosures and hot swappable external bays have their limits. Most are limited to 2tb each. Some are limited to 3tb each, and very few support going up to a 4tb external drive. Can I use this as a stand alone drive outside a NAS or raid? Absolutely. Its spec shows Seagate is more confident this drive will last you longer than one of their desktop drives. This would be a great drive for a non-raid environment. edit: Bought a 10th drive so I updated the numbers in the first section. UPDATE: I'm up to 10 drives now and the only issue I have is 1 drive occasionally timing out. It's timed out 4 times in the past 8 months. It hasn't been kicked out of the raid yet, but I do have a backup ready just in case it happens.