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wrong memory speed?


omniwolf

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Hi,

 

I have Corsair 1GB TWINX-3200XL (2x512) DDR RAM (400 MHz), Xtra Low Latency, Its run in dual.

 

In my bios settings (asus A7N8X deluxe) it says the memory speed is determined by SPD, and the resulting speed is 200MHz.

 

now my processor is an AMD 2800 XP, which is a 333MHz processor (166Mhz FSB, 12.5 multiplier AFAIK, and this is what i have it set at in BIOS)

 

so i dont expect my ram to run at 400MHz, it should only run at 333MHz (is this a right assumption?)

 

i can manually alter the memory speed, so instead of it being "by SPD", i can set a certain percentage. if i set it at percentage 200, i assume it multiplies my fsb by 200%, giving a memory speed of 333MHz (and this is confirmed by the "resulting speed" value changing to 334MHz).

 

but, when i then save the bios settings and it reboots the computer, it says that the system could not start due to CPU overclocking.

 

if i set the memory speed back to SPD (200MHz), it works fine, if i set the memory speed to auto (resulting speed: 166MHz), then it works too.

 

what gives? i should be able to run the memory at 333MHz, right?

 

thanks in advance for any answers.

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Might be a badly worded bios..switching between DDR and Real Mhz values, 200% might actually give you 333MHz / 666DDR which obviously the RAM will not do. When it set to Auto 166Mhz you're ok, thats 333DDR (i.e 333MHz DDR), a 1:1 ratio is best for socket A systems.
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ok thanks, is there a good way to test which is better? is sisoft sandra ok? or is it not recommended?

 

the actual wording is

 

memory frequency - this is where i have the options by SPD, auto, and differing percentages (50% - 200%)

 

Resulting Frequency - what it calculates the frequency to be, but when i set memory frequency to auto, it just says auto here too.

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An unmatched Ratio on Most Socket A and PIV system might actually hinder performance, in a nutshell, if one component is faster than another, then the faster one has to wait on the slower one, thus trottle itself a bit, if both are matched then some harmony is had and things move properly. Running the cpu @ 166 and the memory at 400 will most likely result in less performance overall than 166/166, if your cpu is unlocked then you can try 10x200 for 2Ghz or 10.5x200 for 2.1Ghz, which is a minor overclock (20MHz-ish) for your 2800+ If its unlocked and you run those 200/200 speeds @ 1:1 ratio it'll perform much better.
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hmm so even tho it is a 333MHz processor, its possible to put it up to 400?

 

my mobo is 400MHz fsb enabled i believe.. i heard that you shouldn't overclock your processor by more than 20%.. going from 333 to 400 is a 20.12% increase.. is this still fine do you think?

 

does the fact that im lowering the multiplier from 12.5 to 10.5 lower the risk?

 

do you recommend any system benchmarking so i can test these different settings? (speed as well as stability testing i suppose)

 

thanks again.

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Where'd you hear of this 20% nonsense? :D: The 333 to 400FSB is just the front side bus anyhow, the resultant frequency is a little lower at 10x (2000MHz) and 20Mhz or so higher at 10.5X then your default cpu speed of 2083MHz.

 

http://www.mersenne.org/freesoft.htm -Prime95, select 'just stress testing' then options - torture test, run for 24hrs at least, its prolly the best cpu stress program stability tester there is.

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Its actually 166.6x12.5 = 2082.5Mhz or 2083Mhz rounded, motherboards vary by a few Mhz or so, have seen some deliver as much as 168Mhz for 2.1Ghz but the real figure that standards are set by is 166.6, same for 133MHz, its really 133.3 Stick to Sandra etc.. for benchmarks.
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hmm tried overclocking, anytime i changed the multiplier it would just reset the values and not let me overclock... i could change the fsb from 166 to 200 with no problem, but as soon as i lowered the multiplier from 12.5 to anything, it wouldn't let me do it.. does this mean my cpu is locked?
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