Ever since we reviewed the CORSAIR Neutron GTX 240GB SSD last year, I was somewhat puzzled by the decision to go to a 7mm thin casing. On one hand, this wouldn't affect desktop users at all because most drive cages and trays would still bolt to the standard four screw holes on the bottom of the drive. Even if this was not possible, CORSAIR still included a drive caddy that allowed it to be adapted to a 3.5 inch bay. But when it came to notebooks, the 7mm size was a problem for two reasons: 1. The 7mm size was too thin to fit into most standard notebook hard drive bays and 2. There were no adapters to make it fit.
While many first generation Ultrabooks and slim notebooks may use a 7mm drive, many of them already come with SSDs so the upgrade path is somewhat redundant. What'll confuse even more is that Seagate and Western Digital are both adopting a new 5mm size for their new Solid State Hybrid Drives or SSHDs for short. So now we'll have 9.5mm, 7mm and 5mm drives out there.
For the majority of people looking for upgrades, the 9.5mm size is the standard and discovering that you picked up a 7mm drive by accident is just annoying. ADATA has alleviated the problem with a very simple plastic sleeve that adapts all their new 7mm drives to a 9.5mm height. They plan to start shipping these sleeves with their new lineup of 7mm form factor drives, allowing their products to work in more machines, and annoy fewer DIY upgraders.
So at least with ADATA, if you need a 7mm drive, you've got a 7mm drive. If you need a 9.5mm drive, just pop the sleeve on and you're good to go. Simple.