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After testing a bit later, I've got strange results. Performance degraded for no reason to ATA-100 (133Mb/s). Still faster compare to HDD but strange.
Then after googling a bit and reading blogs I've found out that actually you have to do many things in XP to make SSD work smoothly. Mainly because OS was not designed for them. As a results performance will degrade in time. See Performance Degradation Over Time, Wear, and Trim for more details. The conclusion is to try Windows 7 and see what happens there.