Memory for my new rig

nem2k

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my new computer, tentatively, consists of the following...

C2D e6600
Asus P5B deluxe
evga geforce 7950gt
enermax liberty 500W psu (this will probably change)
creative x-fi extreme music

can someone help me pick out the memory for this system? Im asking because even though ive read as much as i can regarding ram, it sitll confuses me

I need 2gb of it, and im going to be pushing the e6600 to 3ghz+ so I guess this means the ram will need to be overclocked as well?

Im not too sure about what speed and latency ram would be best in this situation, any help appreciated
 

playboyman007

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any suggestions?

im struggling to understand the difference between these...

http://www.overclockers.co.uk/showproduct.php?prodid=MY-092-CS

and

http://www.overclockers.co.uk/showproduct.php?prodid=MY-108-CS

looks the same to me but ones cheaper

Get the Corsair 2GB DDR2 XMS2-6400C4. In your P5B deluxe manual...recommends the CAS 4 version. I read alot of threads about the cas 5 version where people have gotten the black screen of death. Spend the extra money to prevent this problem.
 

rwaritsdario

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In your P5B deluxe manual...recommends the CAS 4 version. I read alot of threads about the cas 5 version where people have gotten the black screen of death.
Thats because they try to OC beyong its potential, which is ~100Mhz lower than the CL4. Dont mind the QVL because any JEDEC aprooved memory will boot and work without a hitch.

@theOP:
For that mild overclock pick any 667CL4, itll run you well up to 3.5Ghz
 

nem2k

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667 is PC2 5300 isnt it?

the thing that i dont understand is this. if i change the FSB by overclocking (i heard that p5b deluxes can reach 500+) dont i need to pick memory that runs at the same frequency? or something to do with ratios?

thats why im a bit worried about which ram to buy, because i dont really understand the relationship between overclocked cpu and the ram
 

rwaritsdario

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667 is PC2 5300 isnt it?
667Mhz equals PC 5300/5400, yes.
the thing that i dont understand is this. if i change the FSB by overclocking (i heard that p5b deluxes can reach 500+) dont i need to pick memory that runs at the same frequency? or something to do with ratios?
Yes, it does. But 3Ghz on a E6600 is only 333Mhz (x9 multiplier).
 

nem2k

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so my memory frequencydoesnthave to match the cpu? whats the ratio?

i thought if your FSB was 400, then you need to run 400mhz ram as well?
 

lewbaseball07

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mmmk...theres a multiplier on the processor and ram. heres an example. Lets just say ur fsb is running at 1066(and its quad pumped. so 266 4 ways). For kicks lets say your processor multiplier is 8 and your memory one is 2(you can change your memory muiltplier higher. But unless you have a intel extreme edition your processor multiplier will be locked but u can set it like lower)

so 266x8=2.13ghz which is your processors clock frequency
....ya...some one..i really forget how the memory multiplier works!!!

soo when you raise the fsb your whole system gets oced...get it now?!?!
 

nem2k

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ok, i read through that, i kinda understand how ram works now, but what is the actual relationship between ram and cpu compitability?

i understand that you need both components running fast enough so that its not the bottleneck. so you increase the fsb to bring it up to speed with the memory controller so its not slowing it down, fair enough. but by increasing the fsb, do you need to alter the memory speed in any way? and if so, how and why? isnt this where ratios come into it?
 

nem2k

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can anyone help me to understand this? the relationships between front side bus and memory bus when it comes to overclocking confuses me...
 

Mondoman

Splendid
Data is transferred between the memory and CPU as follows:

Memory<->Memory Bus<->Memory Controller<->FSB<->CPU

The max throughput of the FSB puts an upper limit on how quickly data can be transferred to/from the CPU. You want to make sure your memory bus speed is set fast enough that it can transfer data at least as fast as the FSB maximum, otherwise it will be the memory bus putting an upper limit on the transfer speed.

With DDR or DDR2, 2 pieces of data are transferred per clock cycle, so if the memory bus is running at 267MHz clock, throughput from a single controller will be 533 MHz data rate.
In dual-channel operation, where two memory controllers are working at the same time, in parallel, data rate is doubled again because of the 2 channels.

The Core 2 Duo FSB transfers 4 pieces of data per clock cycle; current C2D CPUs have a normal FSB clocked at 267MHz, for 1066MHz data rate. Thus, you want your memory to supply data no slower than 1066MHz. For DDR2 running in dual channel mode, a memory clock of 267MHz yields 533MHz data rate per channel, or 1066MHz data rate overall. That's why people suggest running DDR2-533 or faster memory speed for non-overclocked C2D CPUs.

If you overclock the CPU, increasing the FSB, you will need to increase the memory bus speed proportionally to keep up.
 

nem2k

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so that means both the fsb and memory bus have to be overclocked in synch with each other?

how does this affect which memory to buy?

PC2-4200 is 533mhz memory right? so I should buy that if im to go with a 1066mhz cpu like the 6600?

but i was looking at PC2-6400 which is 800mhz memory. meaning the memory bus would have to run at 400mhz. therefore, if i buy that, i can leave the memory at stock, then increase the fsb to 400mhz to match?

and if i go PC2-8500, 1066mhz, id have to increase the fsb to 533mhz to get a 1:1 ratio?

is that how it works?
 

Mondoman

Splendid
so that means both the fsb and memory bus have to be overclocked in synch with each other?
No, but doing so will prevent bottlenecks.

PC2-4200 is 533mhz memory right? so I should buy that if im to go with a 1066mhz cpu like the 6600?
Yes, if you won't be OCing.

but i was looking at PC2-6400 which is 800mhz memory. meaning the memory bus would have to run at 400mhz. therefore, if i buy that, i can leave the memory at stock, then increase the fsb to 400mhz to match?
Yes. However, as with most "performance" memory sold today, you may have to manually set the memory bus to DDR2-800 and adjust the memory voltage, as described here:
http://forumz.tomshardware.com/hardware/modules.php?name=Forums&file=viewtopic&p=1249881#1249881

and if i go PC2-8500, 1066mhz, id have to increase the fsb to 533mhz to get a 1:1 ratio?
Yes, but it's unlikely your CPU or MB would be able to stably handle that speed.
 

nem2k

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ah ok i get it

so basically pc2-6400 ram is fine for me, because as long as i increase the fsb to 400mhz, then ill have a 1:1 ratio

i could also push the memory bus speed to say 450mhz, which also means fsb will have to be increased too

when i receive my ram and install it for the first time, its speed will be slower than advertised. so id need to go into the bios, set the voltage (to...?), set the frequency (to match the fsb), and finally set the latency to match what the product is advertised as

i know im kinda rehashing the same information that you just gave me, but im just trying to get a solid understanding of this...plus im starting to find it somewhat interesting which scares me :lol: