2009 mac pro lion raid 0 slowing down

i have 2 2tb wd caviar black drives raided together. on newly created raid aja speed test gives me 250 read , write speed. been month since created raid , speed has degraded 140 read , write. when raid empty speed 140. causing decrease in speed? tried verify , repair disc permissions no speed gain.

 

anyone?

 

Forums Macs Desktops Mac Pro

• iPhone
• Mac OS & System Software
• iPad
• Apple Watch
• Notebooks
• iTunes
• Apple ID
• iCloud
• Desktop Computers
• Apple Music
• Professional Applications
• iPod
• iWork
• Apple TV
• iLife
• Wireless