So apparently there's been a lot of talk lately about putting in the 1TB hard drives in the MacBook Pros. As attached in the first image, I am running 1.75TB (1TB + 750GB) hard drives in my Core Duo, First generation, MacBook Pro 17" Here's some information about the larger hard drives (As of April 6, 2010): - 1TB, Western Digital Scorpio Blue, 12.5mm, 5200RPM, 8MB Cache, Advanced Format drive** - 750GB, Western Digital Scorpio Blue, 12.5mm, 5200RPM, 8MB Cache - 750GB, Western Digital Scorpio Blue, 9.5mm, 5400RPM, 8MB Cache, Advanced Format drive** The drives I'm currently using are the 1TB and 750GB, 12.5mm height running at 5200RPM spindle speed. So far, only the following systems can support 12.5mm drives in the Hard Drive Bay: 17" MacBook Pro, All Models 15" Unibody MacBook Pro 13" Unibody MacBook (Pro) 13" Unibody Plastic MacBook*** The systems that can support 12.5mm drives in the Optical Bay (Using an Optibay or other enclosures) 17" MacBook Pro, Discrete 13"/15"/17" Unibody MacBook Pro*** 13" Unibody MacBook*** 13" Unibody Plastic MacBook*** For users who wish not to hassle with 12.5mm height, the 9.5mm height is the industry standard for 2.5" Laptop/Notebook Hard Drives. With a 9.5mm drive, you can put it in the Hard Drive bay or Optical Bay with enclosure without worrying about if it'll fit or not. As of April 6, 2010, the largest hard drives are as follows: 7200RPM (9.5mm): 500GB 5400RPM (9.5mm): 750GB 5200RPM (12.5mm): 1TB For performance, with dual drives, you can either use them as dual drives or you can RAID-0/1 the drives together. OSX has the ability to do Software RAID. For more information about RAID, see: http://en.wikipedia.org/wiki/RAID The basics for RAID is: RAID-0 (Striped) is for performance. You get double the bandwidth of hard drives. The drives are also linked. For example, if you have 2x 1TB, in RAID-0, it is viewed as 2TB in Finder/OSX. RAID-1 (Mirror) is for redundancy. Anything that is changed in Disk 0 is also applied to Disk 1. However, if you have 2x 1TB drives, you only have 1TB of usable space since the 2nd drive is a "mirror" of the first. See the screenshot for the XBench and AJA System Test of my set up. Note, I am running 1.5Gbps SATA-I connection. I could probably hit the "limit" of SATA-I with this set up. (Note: I have over 700GB of data on the drives. The OS itself was upgraded from Tiger > Leopard > Snow Leopard) Any problems? I have not noticed any. I do know that the Optical Bay, during shut down, performs a "hard" shut down of the hard drive. Remember though, ALWAYS BACK UP. You can never be too careful. RAID-1 is not a good back up solution. There is no sleep issues, as least from my current uses. -- * Only certain MacBook Pro models can support dual 1TB drives as of April 6, 2010 ** Advanced Format drives are Western Digital's new method of formatting blocks. For more information, see http://www.wdc.com/wdproducts/library/?id=216&type=87 *** Untested, but in theory should work. If any users can comment on this, please post.