memory dividers

[thursday22dp]

Im a little confused what these are for besides overclocking. I didnt see anythingn in my bios for it runnign a nforce4 ultra with an amd64 3500 with mushkin 2-2-2 ram. my comp is oc'ed to 218 x 11 with 2.5-3-3-8

 

[ts3433]

Memory dividers are used for whenever you run your RAM asynchronous with the FSB clock.

 

[thursday22dp]

how exactly do you set them up/what are they useful for

 

[rocketPack]

For example, if you had an nForce2 board with an Athlon XP 1700+ (133MHz FSB) in it, and you stuck DDR333/PC2700 memory into it, you would not be utilizing the memory to its fullest potential by running it at the standard 2xFSB (266MHz). So you apply a DRAM ratio to make the memory run faster than just 2x the FSB.

So, in order for your processor to run at 133MHz while your memory runs at 166MHz (333MHz effective), you need to apply a DRAM ratio of 5:4 (133*5 / 4 = 166).

It really isn't applied to overclocking much except when you're going for pure GHz (you would slow the memory down compared to the FSB so you could raise the FSB up really high to get your processor to run really fast, so the memory wouldn't be overclocked and cause system intsability). Most of the time you want to run it at 1:1 (performance is better when the memory and processor don't have to wait for eachother due to being out of sync).

 

[Spike]

What if you are running a system with a 200 FSB CPU but have DDR433 ram. If you up your FSB to 210 and have a 1:1 ratio your ram is running at 420, 10mhz lower than it's stated speed. Will this hurt it's performance at all even with having the same ratio?

I ask because I have also been confused by all the ram talk. When I go from my AXP 3200+ to a A64 I want to oc a little like I do currently so I have been looking at DDR433 and DDR466 ram. I figured higher FSB ratings was better than lower timings, is that correct?

-spike

 

[thursday22dp]

yeah thats correct spike

 

[rocketPack]

This would require a rather awkward ratio though which would produce very long delays.

Personally I think running the memory slightly under its rating to achieve a DRAM 1:1 is better because the lower clock will allow more aggressive timings on top of being in sync.

 

[thursday22dp]

would i have to set any for mine, a64 35002.2ghz, 2-2-2 ram set at 2.4ghz and 2.5-3-3-8? or would i have to if i OCed higher