No, you cannot do that. You'll brick your card! Which drivers are you using? Try to decrease your core and memory under-volt and see if it makes any difference. Moreover, use the latest blockchain drivers and claymore 10.
Currently I'm using r0binhood's drivers from
https://bitcointalk.org/index.php?topic=2068446.0. My core is operating on 1162MHz, and mem volt is 1000mv, so can you please suggest me what values to try for them?
Tnx.