When it comes to PCs and MACs most people believe that the heart of the system is the CPU with the exception of gamers who naturally put the GPU (graphics card) above everything else. I too had the same opinion almost a decade ago but slowly and after countless of storage related reviews i begun to realize that the true heart of a system is neither the CPU nor the GPU but rather the storage device regardless of whether we are talking about mechanical HDDs or SSDs. You see no matter of what kind of CPU or GPU a system has you can always perform certain functions, perhaps not the highest demanding ones but you can nevertheless. However without a storage device or with one that has but a limited available capacity there`s really that many things one can do especially nowadays when most people have several TBs of data. Now last month we tested the latest Enterprise Capacity 3.5 V.3 4TB SATA III enterprise class hard disk drives (former Constellation ES.3) by Seagate which pretty much dominated the competition. Well today we will be taking a look at the SAS (Serial Attached SCSI) variants which as you will see later on had no issue surpassing their SATA brothers to become the fastest HDDs to ever pass from our test bench."