Prior to updating to OS X Lion, I had one of those hybrid SSD drives installed in my Macbook Pro (a Seagate Momentus). It definitely boosted my computer's performance with much faster bootup times, fast application loading for recently or frequently used apps, etc. I had no problems with it and pretty much forgot about it.
But when I updated to OS X Lion, I had lots of problems that puzzled me for some time before I realized the cause. The main problems centered around rebooting and the computer remembering which apps were open. Even when I turned off features like "restore windows when quitting and reopening apps" and even when I quit apps before rebooting, my computer would reboot into apps and windows that I didn't want. There were several other problems that had to do with preferences for different apps and utilities. It was driving me crazy until I remembered about the hybrid drive. It made sense then, of course. The system was trying to read information from the SSD portion of the drive some of the time, and from the regular part of the drive some of the time... with very unpredictable results.
I replaced the drive with a standard drive and everything worked perfectly. I haven't researched it further since then to see if anything has changed, but at that point, hybrid drives were not compatible with many aspects of OS X Lion.
Missing the speed of the hybrid drive, I finally purchased a full SSD drive and the performance is remarkable and stable.
- Drive hardware faults
For any drive there is a potential for hardware faults to affect its performance. These faults include the development of bad blocks if the storage medium is corrupted, or other hardware problems such as firmware glitches that might result in a specific drive not working as opposed to there being problems with hybrid drives in general. In these cases you can use a tool like Drive Genius, Tech Tool Pro, or Disk Tools Pro to check the drive for bad blocks and test its performance and reliability.
- Volume setup faults
Another option related in part to drive hardware faults: problems with the logical configuration of volumes on the drive. To use the drive, the system needs to set up a partition table on it and allocate chunks of the drive into storage volumes (for example, "Macintosh HD" is a volume on your drive, and not the "drive" itself). If there are problems with the drive's partition table or with its volume format, then the system may have trouble accessing data on it and will spend time resolving conflicts and resorting to alternate means of functioning instead of smoothly performing tasks.
To resolve volume setup faults, be sure you have a restorable full system backup such as one with Time Machine or a file-level drive clone (file-level cloning ensures the file data and organization is copied, without preserving partition tables and volume structures--see more on cloning differences here). Then fully partition and format the drive using Disk Utility on the OS X installation drive (available for OS X Lion if you create a separate restore volume). Ensure you rewrite the partition table by selecting the drive and setting the number of partitions to something different than "Current" (even if you just select "1 Partition"), and when the drive is formatted then restore your backup back to the drive.
- Faulty OS upgrade
Even if the drive hardware is working properly, sometimes faults in software can result in slowdowns after an upgrade. Many times people have existing problems with their operating systems before they upgrade, these problems are then left in caches and other faulty configurations that may result in odd and slow behavior with the new OS version.
To fix faults with the OS configuration, my first recommendation is to run a general maintenance routine on the system to reset these caches and some of the settings that may be causing problems. After doing this, if the problems persist, then try some general troubleshooting steps to see if you can see any improvement by running in alternative accounts, or in special boot modes like Safe Mode.