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punjabiboozer

macrumors newbie
Original poster
Jun 5, 2007
1
0
"Couple thing to understand here...

First, DDR2-800 is not running at 800mhz. The bus speed is half that, 400mhz.

Now, let me give you an overview of the FSB, and the relation between that and your ram speed.

These new chips are kinda like the e4x00 desktop series. In actuality, the FSB is 200mhz [not 800mhz], but 'quad-pumped'. Thus, 4x200=800, and you have an 800mhz FSB.

Now, the ram does NOT necessarily run 1:1 with your FSB speed. Instead your ram speed is determined by a ratio. Your ram speed is the product of both the FSB and that ratio.

So, for example in stana rosa systems...

Running on a 1:1 ratio with the 800mhz FSB C2D should result in a ram speed of DDR2-400. Now, clearly that would offer lousy memory bandwidth, so a different ratio is being used. I suspect in this case a 2:3 ratio is used, resulting in DDR2-600. Now, in a perfect world you could add DDR2-800 modules and it should kick the ratio up to 1:2. Its hard to say if that will actually work though.

From my own personal experience with P965 based desktop systems, you kinda see diminishign returns passed a certain point. The optimal configuration is to push the FSB as high as possible and keep the ram 1:1. In laptops this isn't possible, or practical. Anyway, back to the main point.

Don't sweat the difference. It won't make as large a difference as you might expect."
 
Question, does the new SR chip set support 800?

It has a 800MHz FSB, so it should.

I was just kidding around anyway, DDR2-800 is probably overkill for most conventional applications. Plus its hella expensive (though not as much as the Apple 667MHz upgrade, doh?)

:apple:
 
It has a 800MHz FSB, so it should.

I was just kidding around anyway, DDR2-800 is probably overkill for most conventional applications. Plus its hella expensive (though not as much as the Apple 667MHz upgrade, doh?)

:apple:

This is true. Most believe that that DDR2-800 memory is overpriced vs. the performance. Look at any tech review sites who go into this stuff. In real life the performance is not that much of a difference, even though it costs quite a bit more.
 
But does swapping out the memory void the warranty I'll be paying 300+ for?

No. I specifically asked the girl in chat today that very question. She said, not sure hold on. When she came back she said it is perfectly fine to do it yourself and it won't void the warranty. That is what made me decide to only go with 2GB of RAM. I think a lot of people see the 4GB option not knowing how easy it is to upgrade yourself and just pay the extra price. That might be why Apple charges so much.

If they did void the warranty for such a simple task, they probably wouldn't have this on their site. http://docs.info.apple.com/article.html?artnum=303491
 
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