Which DDr2 memory???

I am about to get the new Conroe duo core chip (having upgraded from a
Athlon 64)

I am a bit confused as to which memory to get for this,

My old system had Corsair DDR with very low latency CL2, now looking at the
DDR2 market there are hundreds of speeds, I want to get DDR2 800 but which
one? I have seen on overclockers.co.uk that they are selling the following:
G.Skill 2GB DDR2 NR PC2-6400 (2x1GB) CAS5 Dual Channel Kit
(F2-6400PHU2-2GBNR) Now the timings for this are 5-5-5-5-15, they are also
selling this: G.Skill 2GB DDR2 HZ PC2-6400 (2x1GB) CAS4 Dual Channel Kit
(F2-6400PHU2-2GBHZ) (MY-013-GS) with timings of 4-4-4-5-15

What is the difference between these as far as performance goes? I noticed a
change when I upgraded my Corsair Value select 1 gig to a Corsair XMS Pro 1
gig stick, will I notice any difference between the above named sticks as
there is over 70 uk pounds (120 Dollars) difference between the CAS 5 and
CAS 4 kits,

Ok, I'm speculating here ....

All of the Conroe chips, I believe, currently have a 1066MHz FSB, which
is a physical clock of 266MHz "quad pumped" (a carryover from the Intel
Netburst architecture) up to 1066MHz.

Since the memory clock is going to be based on the same 266MHz FSB, it's
likely that Conroe motherboards will want 533MHz memory, which is
PC2-4200 (there is 1066MHz memory available, PC2-8500, but it's scarce
and ungodly expensive). It's not clear to me that you would benefit
from anything faster than PC2-4200 in most situations (faster memory
might, however, be required for overclocking). But all of this needs to
be confirmed in the manual for your motherboard.


del RemoveThis @here.com wrote:

> I am about to get the new Conroe duo core chip (having upgraded from a
> Athlon 64)
>
> I am a bit confused as to which memory to get for this,
>
> My old system had Corsair DDR with very low latency CL2, now looking at the
> DDR2 market there are hundreds of speeds, I want to get DDR2 800 but which
> one? I have seen on overclockers.co.uk that they are selling the following:
> G.Skill 2GB DDR2 NR PC2-6400 (2x1GB) CAS5 Dual Channel Kit
> (F2-6400PHU2-2GBNR) Now the timings for this are 5-5-5-5-15, they are also
> selling this: G.Skill 2GB DDR2 HZ PC2-6400 (2x1GB) CAS4 Dual Channel Kit
> (F2-6400PHU2-2GBHZ) (MY-013-GS) with timings of 4-4-4-5-15
>
> What is the difference between these as far as performance goes? I noticed a
> change when I upgraded my Corsair Value select 1 gig to a Corsair XMS Pro 1
> gig stick, will I notice any difference between the above named sticks as
> there is over 70 uk pounds (120 Dollars) difference between the CAS 5 and
> CAS 4 kits,