Need help chosing memory 2x2GB

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Syzygy

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If you are not OCing - er well, nevermind, thats silly.

If you are NOT looking for the highest possible OC with all the headaches of top of the line cooling, fan noise, yada yada. I want to say that with either CPU a nice 8 x 400 with PC6400 ram right on spec runing 1:1 is a very nice sweet spot. But that was back when memory cost an arm and a leg. So even if not going for the bleeding edge get 1066 ram. Brand not all that important.


Why ?

It depends on how much if any you intend to overclock and which CPU, here is why,

q6600 has a max CPU multiplier of 9

9450 has a max CPU multiplier of 8

With the desirable 1:1 memory ratio Intel chipset boards seem to like best and in general are more stable at:

9 x 400 is a CPU speed of 3.6GHz and the memory runs at FSB x 2 = 800MHz with a 1:1 memory ratio/multiplier which is right on spec for the PC6400 800MHz stuff and would be under clocking the faster memory. Now that is a great OC and it will not be easy to achieve unless you do your homework and have excellent cooling. Lets say you cannot get to 3.6GHz, you have three choices.

1) leave the CPU multiplier at 9 and run a lesser FSB which will under clock the ram.
2) leave the CPU multiplier at 9 and run a lesser FSB and hope you have a memory ratio that will run the ram close to 800MHz The lowest (check your bios) multiplier I have seen is 5/4 = 1.2 so at 9 x 350 the CPU would be at 3.15GHz and the ram would be at 350 x 2 x 1.2 = 840MHz and it is certain that increasing the FSB to increase the CPU speed will very shortly require you to loosen timings to CAS 5 as the ram is becoming overclocked.
3) reduce the CPU multiplier to 8 and try 400FSB for a CPU speed of 3.2GHz which should be very do-able and your ram is running right on spec. You then can play with increasing the FSB and you will start OCing the PC6400 ram and it should be good until 420 FSB which would be a CPU speed of 3.36MHz. After that you will most likely need to loosen the timings to CAS 5 and if your board and CPU will do it you will then be good at least until 8 x 450 = 3.6GHz.

With the 9450 and a 1:1 ratio you top out with respect to OCing PC6400 memory at 8 X 400 = 3.2GHz and no matter what you do to get a higher CPU speed you will start OCing PC6400 ram and very shortly would be loosening timings to CAS 5 anyway.

so with the q6600 the pc6400 800MHz stuff will do but there are potential "rough" spots if going above 3.2GHz.
so with the 9450 the 800MHz stuff could be limiting your highest potential overclock. .

Get the 1066 stuff so you do not limit your OCing or CPU choices and dont get in a twist if you under clock it some. I like Corsair, a lot, but I hate MIR more, go with the Gskill. For $10 more than the PC6400 it just lets you have a lot more options and headroom in your settings. Only in some benchmark would you ever tell the difference between cas 4 and cas 5 in a decently OCed and tuned system and if you were going for a high OC you would end up loosening the PC6400 memory to CAS 5 anyway.

I am sure I forgot at least 3 other possibilities but I think you get the drift.
 
from what i understand though a lot of 1066 memory is just overclocked 800 memory. so, there may not be much practical difference between some 800 4-4-4-12 stuff and some 1066 stuff that has to use looser timings and higher voltage to hit its rated speed.

edit: if you look at the reviews of the gskill a lot of people can't even get it running at its rated speed.
 
that's a lot of great info Bill. I think I have read it about 10 times just because I am trying to get a better handle on OCing.
 
Thanks all for the nice comments. A lot of numbers in there but the basic ideas are pretty simple, the rest is just thinking it all through, which is harder unless you have done it before ;)

In case someone is wondering what is behind all the numbers.

On an Intel chipset board (and all others really).

Your cpu speed is going to equal the cpu multiplier x the FSB speed/frequency.

You can reduce the cpu mulitplier (down to 6 if needed) but you cannot raise it above the default and that depends on the specific cpu.

With the desirable 1:1 memory ratio/mulitiplier you memory will run at 2 x the FSB speed/frequency.

If you use a mulitplier the memory will run at 2 x the FSB x the ratio. For example with a 5/4 ratio and 400FSB you memory will run at 2 x 400 x 5/4 which is the same as 2 x 400 x 1.2 = 960 Mhz ( the x 2 is because data is transmitted 2 times for every clock "tic" hence the name Double Data Rate. )


( yep yep the extream edition cpus have multipliers that can be increased above normal but lets not complicate things with $1000 cpus few of us have. )
 
JCDenton said:
from what i understand though a lot of 1066 memory is just overclocked 800 memory. so, there may not be much practical difference between some 800 4-4-4-12 stuff and some 1066 stuff that has to use looser timings and higher voltage to hit its rated speed.

edit: if you look at the reviews of the gskill a lot of people can't even get it running at its rated speed.
Click to expand...

Basically true but I would add one comment, the memory manufacturers have screened and tested (and in some cases "the cream of the crop" from a memory chip manufacturing run is purchased/used by the stick maker) and so you can be sure that the memory will do as advertised. I do not know of any manuf that will warranty (as in replace it) your memory if it will not OC. They of course glady replace it if it wont meet advertsised specs.

That said its a pretty sure bet that good quality enthusiast memory from a big manuf will OC but it is a crapshoot as to how much and forums like this is where we all compare notes and find the "golden sticks". If you look at my posts here a year ago I strongly recommended, over and over again, not buying anything faster than PC6400 800MHz memory. I can still make a strong technical case for that opinion. But with 1066 high quality memory at the prices that can be found today (I have tried to block my recollection of what I paid for the ram in my sig, the pain, oh the pain ! ) I can not justify the 800 is good enough. It just makes things sooo much easier for very little additional money to grab some 1066 and all you can afford (go 2 x 2GB at least) . Before DDR3 becomes dominate and pushes DDR2 prices back up. I have seen this cycle since the days of EDO 64K simms, yes that is 64 KILOBYTES and it was the biggest stick you could buy.

That said, if you absolutely cannot afford the 1066 stuff a good pair of 800 sticks will certainly do.

The real trick and what I forgot to mention is to look at the cpu and memory as a system as they really should NOT be be looked at independently if you intend to OC . They are interdependent if you OC.

Ok gonna be a little mean here sorry, if you mean newegg reviews, 74% of newegg memory reviewers should not be allowed near a computer. With any performance memory you have to go into the bios settings and set the high performance settings manually. The defaults are so the memory will work/boot with any board in the world. I do recall that about a year ago some pc6400 Gskill was out that was a great deal and we/posters determined that to be stable at performance settings you needed to give the ram an extra .1V so that while the manuf said 1.8-.1.9V and if you set it that way you would have issues. But 2.0V solved the problem for 99.9% of people. Little quirks like that come along all the time with all manuf although it does make me wonder about their testing and screening procedures.

As I mentioned I prefer Corsair . I just hate MIR more. If the OP has concerns look for reviews of the Gskill from tech sites. I made the assumption we were talking about newegg reviews, if that is not the case, 1) sorry, my bad, and 2) got a link ? .
 
I just picked up the G.Skill memory you posted a link to. I'll let you know in a week or so how i like it if you have not already decided.
 
I have the G.Skill set you linked and had no issues with it. Only tip on it I have is to check your voltages in BIOS if have an issues. G.Skill rates it 2.0-2.1V most BIOS seem to have a lower default voltage.
 
Gskill is good memory, but I'm trading out my 4gb of Gskill for 4gb of Dominators.

I wish the 2gb sticks of ballistix weren't so flakey. :( My 2gb of Tracers was my favorite kit of rams. :(
 
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