That depends on whether you want to overclock or not, or if the extra 200mhz on the base clock is worth the extra 25 bucks to your or not. I think it's worth it, but you may not. Both are good enough for almost anything you want to do, so in reality, if you have no plans to overclock and aren't specifically concerned with the stock clock speed, the locked chip should be fine. Otherwise, go with the K SKU chip.