Overclocking

i have overclocked my hd 5450 1gb from 650 core to 850 core stable. But when i try to do the same with the memory it starts showing artifacts beyond 680 which is very low. Will such a configuration with high core and low memory make the card unstable. Also is there any other way to overclock the memory further?
i use amd gpu clock for overclocking and gpu tool for stability check.
thank u

You just got a card that has RAM that doesn't want to OC... Unfortunately there's no way around it unless you solder some better ram on it =D
Otherwise, having a high gpu clock with lesser clocked ram wont make it unstable... You just have to test to see what it likes.

The stock clock for the memory on that card is 400Mhz and your surprised it can't overclock past 680Mhz? That's way over a 50% overclock!

Anyway Core clock is what counts, it'll increase the performance the most.

BTW I have the same card and even when its overclocked to the limit its still ***.