I had a qucik question for you guys. For gaming how much of a difference does core memory clock and effective memory clock if it close. For example I'm looking at the Radeon 6970 graphics card and within the 6970 there are two different cards. All 6970's have a streaming process of 1536 but the cheaper cards have a core clock of 880 and an effective clock of 1375. The more expensive 6970 cards start out at a 900 core clock and 1400 mhz effective clock. So how much of a difference does the 20mhz core clock and 25mhz effective clock make for gaming? Also is it worth it to spend an extra 30+ dollars for 20 and 25mhz more power.