Actually, it has only a little to do with FSB and more to do with the data
transfer rate. Though FSB is many times used in line with what FSB mostly
pertains to the speed of the CPU connection to the northbridge, while bus
more is reference in the case of memory; they are used interchangeably
though. The numbers in question are related to data transfer rates overall
(1600=12800MB/s). The series of numbers are the timings, and they have a
distinct effect on the transfer rates. The higher, the slower. But
typically, if you have a 1600mhz set of DDR3 triple channel memory, having
run at the lower timings can cause delay and burps because of temperature
discrepancies. More importantly, it can cause the CPU to overheat if the
voltage is mismatched where they are higher on the memory side. Unless one
is pressed for time in the nanoseconds, having run on low latency just to
attain them isn't going to offer much. I use 1333mhz set on auto and I get
speeds that can run as well as 1600 set on 8-8-8-24. If you are going to use
1600mhz memory or higher, refer to your CPU specs and the temps that the
memory will run when at their recommended speeds.

Unless one is doing serious graphics and especially gaming, you really don't
need memory that fast.

-----Original Message-----
From: Personal Computer Hardware discussion List
[mailto:[log in to unmask]] On Behalf Of Dean Kukral
Sent: Monday, November 29, 2010 6:29 PM
To: [log in to unmask]
Subject: Re: [PCBUILD] RAM specs

Well, I have been waiting for someone who knows what they are talking 
about to answer this, Peter, and since nobody has, I will step in and 
give you my understanding.

First of all the  "1066" and "1600" refer, I think, to the FSB speed.  
(Front Side Bus.)  The 1600 can be reliably run at a much faster speed 
(is certified to run at a higher speed) than the 1066.  Higher CLOCK 
speed of the FSB.  The other numbers are the number of clock cycles to 
do individual operations in the accessing of the memory.  Since they are 
clock cycles, they are not a reliable indicator of speed except relative 
to the same FSB speed.  In this case, if your motherboard (FSB) will 
support the 1600 chips, then you will get significantly better 
performance than with the 1066 chips for those operations that require 
the memory access.

If somebody wants to give a better answer, I am happy to yield the 
floor.  :)

Dean Kukral

On 11/28/2010 4:07 PM, Peter Shkabara wrote:
> I thought I understood RAM, but I find myself confused now. Looking at two
> 240-pin DDR3 SDRAM specs.
>
>
>
> RAM 1: rated as DDR3 1066 with timing of 7-7-7-18
>
>
>
> RAM 2: rated as DDR3 1600 with timing of 7-8-7-24
>
>
>
> What I don't understand is why RAM 2 has a faster clock interface
(1600MHz),
> but its timing is slower! Which will be faster in a system? Any
explanation
> or pointer to references will help. Thank you.
>
>
>
> Peter Shkabara
>
> --------------------------------------
>
> [log in to unmask]
>
>
>    

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