"The ATI Radeon HD 3650 is the direct replacement for the ATI Radeon HD 2600 Pro as you can tell from the chart above. The ATI Radeon HD 3650 is active cooled with a core clock of 725MHz and a memory clock of 800MHz and will be available with two kinds of memory ICs - GDDR3 and GDDR2. The slower and older GDDR2 memory chips will be used on the $79 price point cards, while the $99 cards will feature faster GDDR3 memory ICs..."
Check it out at Legit Reviews. The reviewer says both cards don't really impress but are a nice choice if you only want to spend $50-100 on a graphics card. If you want good gaming performance it's a better idea to shop for a Radeon HD 3850.