I got a 250GB Samsung 840 EVO SSD a couple days ago to replace my old HDD. It is connected to a SATA3 port, AHCI is enabled, and I ran the optimizations included with Samsung Magician. The benchmarks for sequential read/write are on par with what they should be (554MB/s and 523MB/s respectively) and random read/write are a bit lower (65723/56396). Magician reports that the drive is healthy.
When I installed Windows 7 Home Premium 64-bit, I noticed that it took a pretty long time to install (I don't have the exact number of minutes, but it was a good bit longer than installing on my old HDD). After the install, I got a couple lockups and crashes and I noticed that booting up took a very long time. This morning I updated everything I could (including the BIOS) on my motherboard (ASUS P8Z77-V LX) and I haven't had a crash since, but I timed my startup process and from the moment I powered on to the time the computer was ready to go, over 4 minutes elapsed (though about 30 or so seconds was just getting past the BIOS). With my HDD, this time was significantly lower.
Also of note, I have a wireless mouse, the receiver of which is plugged into a USB port on the motherboard, and it takes roughly 30 seconds for the mouse to begin working after my desktop appears (I hear the sound Windows makes when a new piece of hardware is attached before it becomes responsive) and I have a USB wireless network adapter also plugged into the motherboard that does the same thing. My keyboard (wired PS2 connection) is responsive from the get-go. Additionally, the mouse is responsive in the BIOS.
Once the computer is up an running, however, it behaves well (barring the crashes) and is very quick. It's just the painful start-up time and the issue with USB devices that I need to find a way to fix.
I am running an Intel Core i5 2400 with 8GB DDR3 memory. If anybody has any ideas as to what may be causing this or potential solutions, please let me know. If you need further information, I would be more than happy to provide it. Any advice would be greatly appreciated. Thanks.