After the keynote I will be switching to the light and purchasing my first iMac and intend on installing 2X2Gb 667 sodimms to avoid the apple ram premium. From what I gather this isn't a problem, but when searching local computer outlet stores there are two variations from the well known brands. Value Ram and Standard. The only thing that seems to be different is the recommended timings on value ram are CL5 instead of CL4. Both have the same claimed production standards and lifetime warranty. Will this affect the iMac performance? Any help would be greatly appreciated.