CPU fsb 1066 = mem fsb 1066 a must right?

ghb70005

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If I'm looking at the Intel core 2 duo e6x00 Conroe
All versions have a FSB of 1066
Does this dictate that getting memory with a FSB of anything less that 1066 would create a bottle neck in performance, hence a waste?

And if I insist on getting Corsair mem than the twin2x2048-8500c5 is the mem for me right?
 

zenmaster

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OK, to simplify.

What you want is memory that runs at 533 for CPUs that use a FSB of 1066. (DDR2 533)

Faster ram will be a waste of money unless you over clock.
More Conroe's can overclock very easily and other chips may soon have a faster FSB so slightly faster ram may allow you to OC or upgrade your chip in the future w/o replacing the ram.

It all depends on price difference.
I dont think I would get anything faster than 667 since it does not sound as if you have a strong desire to do serious over-clocking.


Slower ram could cause the system to run much slower as the FSB would need to slow to which would effect the CPU speed and cause it to slow. I could even see the system not booting with something like DDR2 400.
 

chuckshissle

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Overclocking wise it's good to have the highest ram frequency as possible for overclocking headroom. But you can run it with DDR2 533 and pair with the 1066 cpu, it would be 1:1 ratio. So if you go stock settings then the DDR2 533 is good but anything higher would be better.
 

-silencer-

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Basically, this is how it goes:
A CPU fsb at 1066MHz is a quad-pumped motherboard fsb of 266MHz. Since RAM is DDR (double data rate), that would be 533MHz. So you only need DDR2-533 to run your Core2Duo at stock speed. However, if you get DDR2-667 or DDR2-800, you're guaranteed at least some overclocking headroom. If you pick CAS4 or CAS3 memory at a certain spec'd speed, most likely it'll overclock higher than CAS5 memory at the same spec'd speed.

I'd go for the best bang for the buck for moderate overclocking.. DDR2-667 CAS4. I've never had a problem with this memory (Corsair, Crucial, mushkin, Patriot brands) getting to 800MHz at 5-5-5-15 timings. A pair of DDR2-667 CAS5 sticks might get you to 800MHz, but they might not make it past 700-750MHz at 5-5-5-15 timings. In fact, many companies use the exact same modules on the 667C4 and 800C5 sticks - just pre-set at different speed/timings (with the higher speed/higher timing sticks priced $10-$40 higher, even though they're the same).

2x512MB Corsair XMS DDR2-675 CAS4 is $109 at newegg.
There are a few 2x1GB DDR2-667 CAS4 models in the $210-220 range at newegg, and the Corsair model is $240 ($210 with the $30 rebate).
 

ghb70005

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With current newegg prices after rebate

TWIN2X2048-5400C4 $209
Timing: 4-4-4-12

TWIN2X2048-6400 $214
Timing: 5-5-5-12

TWIN2X2048-6400C4 $236
Timing: 4-4-4-12

looks like 64 series is the best pice performance deal
but I need to read up about the timing.
Dont understand the effects of lower timing with same mhz rating to justify $22 increase.

Good chance I'll OC slightly upon further researching of the details.

Thanks for helping this novice.







1
 

zenmaster

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Another thing to keep an eye on is voltage.

The standards state this should be 1.8v

Some motherboards will detect ram that requires more voltage and automatically increase it to allow the RAM to work.

Other boards will simply fail to boot with the higher voltage ram.
In such cases you may need to boot the PC with a single cheap stick so you can get into the bios and change the ram voltage setting to match what you RAM needs.

So, any Ram above 1.8v has the potential to cause you some headaches.
The faster the RAM is rated, the more likely it will have greater than 1.8v.

This is not inherently a sign of bad ram, just something to keep in mind that you may need a cheep stick for boot strap purposes if you go for real high speed memory.
 

ghb70005

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Hmm further thought..

5400C4 timing 4-4-4-12 is good because I can up the timing to 5-5-5-15 and get 800mhz in order to OC my cpu.

While the 6400 timing 5-5-5-12 gives me marginal gain if I up the timing to 5-5-5-15.

And 6400C4 timing 4-4-4-12 gives a novice like me too much when I up the timing to 5-5-5-15 because I probably won’t OC my e6600 enough to use it all.
 

stefx

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Ok, so if I understand right, if I want to overclock my e6600 to 3.6GHz max, I need DDR2-800?
Please confirm

I just want to make sure I don't need DDR2-1000, because those are pretty expensive

Thanks
 

skuzzy

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I think understand now! If I get 800Mhz RAM and do not plan on overclocking, I have wasted money as 533Mhz RAM would work just as well.

I will pick up 667 just in case I want to play alittle, but thanks folks. This thread was extremely useful.

I wish we could rate threads.