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memory cpu timings

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sucky noob

Member
Joined
Aug 14, 2003
hey guys, i recently overclocked my 2.4c to 2.7, but it wont go any higher, and it is kinda unstable. i remember hearing about changing the memory ratios or something like that. can anyone explain that to me? i have an is7-e. thanks
 
i would be shoked if thats all ur 2.4c will run. if i were u id go into the bios and set the memory ratio to 3/2 just to see how far u can push the cpu,also set the voltage as hi as it will go 2.8-2.9 and set the timings real loose. then let her crank.. once u have found the cpu's limit , reset the ratio to 5/4 and since u already know how far the cpu can go.youll be able to test the memory to its max.... have fun flapper...
 
you may see a setting in the bios to put the ram at 320mhz, this is the 5:4 ratio, 260mhz is 3:2 i think. 400mhz is 1:1. put it in 5:4 or even 3:2 and crank 'er up.
 
yeah, my voltage is on auto, but i thinnk its at 1.525 default. i really havent messed with any other settings other than the fsb. so let me get this strait: the fsb is 200MHz and then multiplied by 4, the RAM is 200mhz multiplied by 2. So at default, this would give it a 1:1 ratio. Is what im sayin here correct? Am i on the right track? When i crank the fsb up to 250 oh no i've gone cross-eyed.
 
yes, the fsb is 200mhz and its multiplied by 4 to get the 800mhz fsb advertised. the memory is dual channel ddr400, so its 200mhz multiplied by 2 to get 400mhz. this doesnt seem like 1:1 to me, 1:1 should be 800:800, but anyway, that is what 1:1 is (i think its cuz before they are multiplied they are both 200mhz). if you crank it up to 250fsb, your memory needs to be able to do that too (250mhz), so you need ddr500 which is pc4000, or some good overclocking pc3500 or pc3700. that, OR you can use the 5:4 divider, which may be something like ddr320 in bios, this way, if the processor is running a 200mhz bus, you only need memory that can do 160mhz, or ddr320. so now, if you crank it up to 250, your fsb is increased, but the memory speed is not (250fsb x 4 / 5 = 200mhz on the ram x 2 = 400mhz = ddr400). does this help or is this confusing?
 
That helps. thanks. ive been able to get it up to 3.3ghz stable EXCEPT when i go that high, MY SOUND CARD IS INACTIVE. i go into control panel and it seems as if my computer has never seen my sound card. what the heck is going on????
 
did you lock the pci bus? you mobo whould have an option called pci lock or something like that it must be locked or the pci bus will also be overclocked.

if the pci bus is overclocked MANY other periphials will quit responding including your hard drive

try locking your pci bus
 
gustay - the RAM isn't 400Mhz because it's dual channel. If the ram is set to 200Mhz, then it's running at the 800Mhz advertized FSB, because Intel quad-pumps the RAM. Amd, on the other hand, using the rising and falling of the signal (don't ask me to get more technical, because I don't know enough to say it correctly), so it double-pumps it, therefore you double (instead of quadruple, like with Intel) the speed the RAM is running at the get your advertized FSB rating.
 
PerlAddict said:
gustay - the RAM isn't 400Mhz because it's dual channel. If the ram is set to 200Mhz, then it's running at the 800Mhz advertized FSB, because Intel quad-pumps the RAM. Amd, on the other hand, using the rising and falling of the signal (don't ask me to get more technical, because I don't know enough to say it correctly), so it double-pumps it, therefore you double (instead of quadruple, like with Intel) the speed the RAM is running at the get your advertized FSB rating.

intel does not quad pump the ram. intel quad pumps the FSB. if you look at CPUZ you can see the FSB is 275 MHz, yet the bus speed below it is at 1100 MHz. 1100 Mhz divided by 275 MHz = 4, or the quad pump.
scorpionkng3333-CPUZ.JPG


intel does not quad pump the memory. PC3200 is rated at
400 (see here). it starts out at 200mhz, but since it has memory on two sides its doubled to 400mhz. thats as fast as it gets unless you overclock, it doesnt go anywhere near 800mhz, you need Rambus for that.

im not sure how dual channel works (all i know is it doubles bandwidth) or how the ram matches the speed of the bus which turns out to be 800mhz, hell i dont even know how multipliers work on cpus (i mean, how can it multiply to get clock cycles?) and i dont know how they can quad pump the FSB, but what i do know is the memory (at least ddr) does not run at 800mhz, some very lucky people have gotten komusa to run 600mhz...maybe starting a new thread would answer this?
 
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I think you misunderstood what I was trying to say. The "dual channel" part has nothing to do with the final FSB speed. PC3200, run at it's stock speed (200Mhz), will yield a 800Mhz FSB on an Intel system (that supports the quad-pumped speed of 800Mhz, of course), and will yield a 400Mhz FSB on an AMD system, which "double pumps" it (400Mhz is the double-data rate of the initial 200Mhz). When I said "it," I meant the system, not the actual RAM speed ... I'm talking about total FSB overall.

DDR RAM doubles the bandwidth of the memory by transfering data twice per cycle, using both the rising and falling edges of the clock cycle. AFAIK, this is how AMD utilizes the RAM, while Intel takes that same RAM and quap-umps out the reading of the cycles, yielding 4 times the initial 200Mhz on PC3200.

Just wanted to clarify, because you can run these FSB speeds with one or two sticks, dual channel non-withstanding.
 
ok, so you were saying the FSB is 800mhz and not the ram, because the ram cannot run that speed. the ram cant just be doubled speed on an intel system becuase they have the quad pump on the FSB (4*200mhz=800mhzFSB). on an intel system or an amd (400FSB barton) that are not overclocked, pc3200 will run pc3200 speeds.
 
Correct. But PC3200 speeds on an Intel system equal a total FSB of 800, where it only equals a FSB of 400 on AMD systems.

But AMD makes better use of tight timings, where Intel makes better use of higher bandwidth. So they come out comperable in the end. Either way, your PC3200 RAM is still running at 200Mhz.

Just wanted to clarify that running in dual channel doesn't affect that, in case you thought you couldn't run those speeds in that mode. :)

Best wishes,
- Dave
 
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