@Katamari2017 buy/build mode is probably less complicated then play mode therefore takes less processing power to execute. The graphics for TS3 could be demanding and certain packs are more demanding then others - example Seasons is more graphically demanding then some other packs. Your computer's cpu has to provide the graphics chip with data fast enough to produce the screen so a weak cpu may appear to be a graphics issue. Physical memory could be an issue. The Sims 3 is a 32 bit application so the game can not access more then 4Gb of memory - actually the game uses only about 2Gb of memory due to the compilers used to create the game. There are other applications and/or services that use the rest of the memory. A gaming computer should have a minimum of 4Gb of memory for a 32 bit system and 8Gb for a 64 bit system. Again a more powerful cpu could provide data faster. And of course the motherboard needs to be designed to handle all the data as fast of the components can handle the data. Most gaming computers perform only as good as the weakest component. It's all about how fast the computer can get data from one place to another. It is a balancing act. Putting a $500 graphics card in a computer with a slow cpu will probably won't help much. The whole computer needs to be analyzed to make a proper recommendation.