Ram Question

[Koolpc]

What is the difference between CAS 4-4-4-12 and CAS 5-5-5-15 Will they work together ok?

[Aez]

cas4 is slightly faster and yes they will work together but will run at the speed of the slowest ram.

[chrestomanci]

What is the difference between CAS 4-4-4-12 and CAS 5-5-5-15 Will they work together ok?

They refer to the number of clock cycles that the RAM takes between a request for data, and the delevery of that data. The clock cycles refer to the clock speed of the RAM, not the CPU. So for example, if you have DDR 3200, then it has a clock speed of 200MHz, so CAS-4 ram will take 4 cycles between request and delivery (20 nanoseconds)

If you mix speeds of ram in the same system, then the whole system will run at the lowest common denominator, so in your case everything will run at CAS 5-5-5-15. The difference in performance will be measurable, but not very large. You may find that you get better performance from having more memory, of from having a small amount of fast memory. It depends what apps you are running.

There are more detailed explanations out there on varous hardware sites, check Google.