I already have a seagate barracuda 500 gb (6gb/s) and was wondering about getting another hard drive because of the current sales on new egg I was wondering if it would effect my speed at all if i got another hard drive at 3gb/s if it would effect my speeds
Nah dude, i have 1tb 3gb/s and 2tb 6gb/s no problems with speed. Just go for it.
Mechanical HDD's cant even saturate the bandwidth of SATA 3gb/s so you shouldnt see any difference.
i would say Mechanical HDD's cant even saturate the bandwidth of SATA 1.5 untill you use 10,000 rpm or 15,000 rpm but they cost more per gb than ssd's