Hi, I'm planning to buy an iMac for my interior design works. I will have to do lots of 3D modeling as well as rendering. After swiching from PC to Macbook Pro, I'm totally in love with Mac OSX, I trust the os itself. So now, here me, an Mac fan boy ). My question is last week, my friend purchased a built-to-oder PC, cost around SGD$1700 (screen included). Here is her spec 2.93 GHz Intel Core i7 CPu 870 4GB DDR ram 2x2GB 1TB SATA NDVIA T220 256MB While the iMac 27" that I'm looking at is nearly the same spec but cost SGD$3100 2.93GHz Quad-Core Intel Core i7 4GB 1333MHz DDR3 SDRAM - 2x2GB 1TB Serial ATA Drive 8x double-layer SuperDrive ATI Radeon HD 5750 1GB GDDR5 SDRAM I know the screen of iMac is nearly unbeatable in the market right now and the OSX is what I'm in love with, but is there anything else that make the different in these 2? And why it is Intel core i7 not quad-core i7?? Its the same rite?