Everyone has their personal threshold when it comes to stability. For some people, one crash a day is acceptable and for others one crash a month is not. Just remember this, if you're getting artifacting then your system is probably suffering instability due to heat. Heat = bad, so don't start crying if and when your system burns itself to a crisp. I would just lower the clock speed a bit. In my opinion, the extra 5 fps isn't worth the risk of damaging a product.