Did you scan virus? Some viruses make the hard drive slow down.

Did you solve the problem ?
 

For some strange reason i had the same problem today on a buddys computer... he is running windows 8 dont know if thats the case for your rig aswell ( and im not entirely sure it has to do with it )
i upgraded the bios... ( gigabyte motherboard ) seems that there is an issue with certain bios releases...
found this... http://forums.anandtech.com/archive/index.php/t-2192825.html

after i turned back to the previous bios update things still were not working had strange readings from the crystalmark aswell so i looked at the next thing energy settings ( windows )
I normaly make sure after i installed everything that the energy level is set to full throttle ( max power )
turns out that after the windows update these settings had been set to Energy save... turned it up again restarted and ran another test and well things are back to normal...

SO im not sure if it was the bios update or the windows update itself... you could try and set the energy level to max if that doesnt change there is a small percentage that the bios version if you updated is the cause... But before that try the energy settings in windows
Personally i never do a bios upgrade on my boards when things run as they should but my buddy wanted it all updated... Thats the reason i did it...if it was running on the same bios version before there is no need to worry about an upgrade... but if you did you might wanna go back but test windows settings first

Will read back later to see if this helps you or not... 

 

YAY!!!!   I secure erased and did a clean install of Win7 back my high write speeds. Reading a tad slower though. Oh swell.

I must have had a setting wrong?

Your PC and SSD's are fine Jim, SSD's lose speed as they get more data on them is all, but they are still faster than a standard drive.

when i had my ocz ssd, i tried in vain to get their tech support people to answer my questions regarding read and write speeds decreasing. after a week of back and forth email messages from china (they no longer had a direct tech support phone number), i gave up on ocz and called corsair to ask which model of theirs they recommended for my use. i described my dissatisfaction with ocz tech support to the tech guy from corsair and he helped me getting it to function properly. a secure erase and reinstall is what he recommended i do and it worked. needless to say, i bought a corsair ssd and got rid of the ocz as soon as i could. anyway, i was also told that an ssd will slow down as more data is added to it. this is especially true if the free space on the ssd is less than half of its total capacity. i keep all my temp files of any type on a platter drive because of that. currently, i have 2 corsair force gt 120 drives in a raid array and the speeds for it have slowly decreased over time. i have 2 samsung 840 pro 256 drives on a shelf across the room that i want to install but i'm too lazy to reinstall everything again right now. i was using a solo 840 pro but it failed and i had to revert to the twin corsairs for a bit. ramble ramble ramble. lack of proper punctuation and capitalization. disjointed thoughts galore. where's the paragraph break?

" and the speeds for it have slowly decreased over time"

My speeds cut in half overnight. Faster, actually.

I secure erased yesterday, fresh install, added updates and drivers, good speeds.

Added my programs, speed cut in half. The 256 GB drive is less than a third full.

OCZ says I need to replace it. Tech support is having me run ATTO in I/O Comparison mode to test for a bad drive. It's a pass or fail test.

We shall see........

Redneck, before you RMA, take out the graphics card you just put in and rerun the test. I'm wondering if the graphics card forced the board to lower the bus speed.

Can't edit. First part of the above was a quote, of course.

Do you do the test before or after you install the gfx card drivers? Do you know if the Southbridge frequency has changed at all? Have you tried swapping cables on your SSDs? What kind of performance tests have you been doing and for how long?

ATTO was used by request by OCZ and results sent to them, which is why they say the drive needs replaced.

Good article, Savyg.

UPDATE:

OCZ sent me a new Vertex 4.

Rated higher than my Agility 4, costs about $130.00 more than I paid for the Agility 4.

I'm happy...lol.