And playin games i saw that the FPS has low performance every some second and using the HWiNFO 64 i see that the CPU is unstable and down from 3,388 Mhz to 797,4 (aprox). Every time that the frequency down i have low fps.
How can i stabilize the CPU frequency?
Sorry, but heat and power are your problems. The original CPU was a 45w device. The new CPU is a 55w device. The new CPU runs hotter (and faster) and it is more than the heatsink can handle. You can try using a premium thermal compound and making sure your intake and exhaust ports are clean, but I really think you need to go back to the original CPU to have any chance of stability.