Windows 7 - CPU i3 550

Does CPU i3 550 supports RAM 1600 mhz speed?

Not according to Intel,

Intel® Core

I don't know whether any of the current Intel processors officially support anything over DDR3 1333. That's the highest frequency listed for the I7-2600k (fastest desktop Socket 1155 chip). The I7-990X (fastest Socket 1366 chip) only lists DDR3-1066.

Higher RAM frequencies are available with motherboards that permit overclocking.

Thanks, my PC showed blue screen every time when I have installed OCZ PC 12000 I removed it and install g. skill PC 10600 now works with no problem

When I've put faster RAM in a PC and let it use the default settings, I get the normal frequency for the PC, not the RAM. (That's DDR3-1066 on my current system.) I need to manually set a higher RAM multiplier in the BIOS to get the rated frequency. I also have to make sure that the RAM voltages and timings are set to the RAM maker's specs.

Some PCs can be set to use the XMP information in the RAM, if it's present.

If you don't want to mess with that stuff, stay with RAM intended to run at the normal frequencies.