X220 faulty EEPROM possibilities now by 2015

[CPC464]

Hi,
I've got a maxed out X220 as main computer, since 2013.
- Core i5 2520m
- 16 Gb DDR3
- 1Tb HD
-120 Gb SSD
- IPS
I don't want to replace it, I don't like the 6 row chiclet Keyboard in the X230, and X240-X250 are not real Thinkpads anymore for me. This X220 still must last me for a while.
Now I've got the opportunity to get a working Core i7 2640m motherboard. I know it's only a bump of about 10% in CPU Power, but since everything else is already maxed out, and I'm not planning to buy a newer X2X Thinkpad, it were nice...
This I7 motherboard is manufactured in december 2011, my current i5 motherboard is manufactured in june 2011. I've read that some boards made between september and december 2011 could be affected by the faulty EEPROM problem, but, according to what I've read, the boards with faulty EEPROMs die usually within the first year of life.
So, my question is... Should I still be afraid about this i7 board (it has been working flawlessly for almost 4 years)? Should all the uade faulty boards be already dead now, by 2015?
Thank you!

[Puppy]

There is long thread about it https://forums.lenovo.com/t5/X-Series-T ... -p/659779/ and last report is April 2014.

I have X220 bought in May 2012. I don't know the exact motherboard date but it was one of last X220 boxes available before the X230 design failure appearance. I still have effective warranty till April 2016.