SSD vs. HDD performance chart (from Computer World)
Intel 520 Series SSD/Western Digital WD Black HD/Seagate Momentus XT Solid State Hybrid Drive
First/third boot-up time
12/9 sec. 20/21 sec. 20/12 sec.
Max. read speed (4K blocks) 456MB/sec. 122MB/sec. 106MB/sec.
SSD much faster, hybrid somewhat faster
Max. write speed
241MB/sec. 119MB/sec. 114MB/sec.
SSD much faster, slightly faster
1.19GB file transfer
15 sec. 34 sec. 29 sec.
SSD much faster, hybrid slightly faster
First/third time opening a 372-page Word doc.
57/10 sec. 48/9 sec. 58/10 sec.
Windows caches disk info in RAM. If the info is cached, the second time you open something it doesn't matter what drive you use. Also, here in this real-world application the HDD was the fastest.
Opening a 10MB PowerPoint document
2 sec. 2 sec. 2 sec.
Most people here would not recommend SSDs as they are not cost efficient and in PCs give little real-world benefits over hard disks. My comp boots to the Windows 8 desktop in less than 18 seconds with a WD 640 GB SATA 6 GB/s Caviar Black and loads programs plenty fast. The only reason that I might opt for an SSD is if I were building a super quiet computer.
My Western Digital drive is SATA 3.0 and has a 64 MB cache; in the real world it's pretty fast. Don't just go by benchmark values; find a review that compares how real-world computing actions differ when assessing hardware components and software.