I am building a new comp and just had a question about the case. It will be a cm690 and I was just wondering about airflow & cooling. I will be running a q6600 SLACR with a Xigmatek HDT-S1283 heatsink atm. Do I need to purchase and install the 4 optional 120mm fans to help with cooling. I plan to overclock the CPU to 3.2ghz. If I do get the fans, will I need high CFM fans (70+) or just standard fans. I want to keep the temp at load on the CPU between 50-60c. Also, which PSU is better - Antec Neopower 650w or Silverstone ST75ZF?