Which One Should I buy Because they say if you use all 4 slot it puts strain on the memory controller. Also, Will 1600 be good enough for i7 2500k or should I use higher mhz like 2133 or 2200. Because I heard that intel like mhz and amd likes low cas and the 2200 has cas 7. Apparently I hear a lot of things lol, But I do search a lot in forums and benchmarks.
I suggest 8GB (2x4GB) DDR3-1600 CL9 1.5v RAM. The most important number is the voltage -- make sure it's 1.5v or you could have problems later. Lower-latency RAM won't make any noticeable difference, so save the money for something that will, like a more powerful graphics card or an SSD or something.
not true cas latency is more important than ever... if you can get your ddr3 1600 cas latency down to 6 or 7 you can outperform ram that runs at 2100+ c9 if you can get the best of both and get fast 2200+ c7 then your bandwidth will be stunning. infact it will be more efficient than ddr2 1066 running at cas 3 which is pretty damn good anyway.
the faster the ram and lower the cas will have an impact on your system performance. the ram speed will show in high end apps only like benchmarks and transcoding but cas latency will help with everything. as its not restricted the same way as ram speed.