Disclaimer: Everything discussed here in this post is out of pure curiosity and educational purposes. If you wish to discuss the benefits of overclocking a GTX550 TI in 2016 instead of buying a new card, please skip that thought.
In my quest of staying 5 years behind in technology, I have obtained an MSI N550GTX-TI Cyclone II OC (blah blah blah...) from UCC after following @VANGUARD bro's post. Yesterday I tried to OC it, to see how much can I go, just out of curiosity. But I cannot OC it even a little bit. If I increase the core clock just 5 MHz to 955 MHz (from it's factory OC 950 MHz) it starts racking up error's on OCCT's GPU test with Error Check, and display driver crashes within 5 minutes in any game. The more interesting thing is even if I increase the core voltage (tried up to max 1.15v from it's stock 1.062v) it still behaves the same.
Is there something that I'm doing wrong here? A quick google shows me a lot of people going well above 1000MHz with this card. Even if the chip I got is the worst cherry picked one, if it is able to run stable at 950MHz at 1.062v it should OC at least 5 MHz with a 88mv voltage boost, right?