Memory ratio's

jokers_greg · Feb 6, 2005

The more I read, the more confusing it gets. What is your RAM ratio, how do you change it (if you can) what determines the ratio. What is the best ratio etc. If someone can clear all (or some) of that up for me, it'd be very helpful.

Thanks :attn:

Sucka · Feb 6, 2005

jokers_greg said:
The more I read, the more confusing it gets. What is your RAM ratio, how do you change it (if you can) what determines the ratio. What is the best ratio etc. If someone can clear all (or some) of that up for me, it'd be very helpful.

Thanks

There are typically 3 ratios to choose from, 1:1, 5:4, 3:2. Bassically what it means is this. On a 1:1 (optimal) your memory is going to be running at the same speed as your processors front side bus speed. For example: If you have a Pentium or A64, the default front side bus (or HTT on AMD) is going to be 200MHz, therefore the memory will run at 200MHz, which in DDR would equal 400MHz (or 2 x 200MHz). Now if you wanted to run in a 5:4 ratio, what that will do is drop the memory down to 80% that of the CPU's front side bus. So say you could overclock the CPU to 250MHz, but the memory is only rated to DDR400, you would set it to 5:4, and it would run 80% of the front side bus, or drop it back down to 200MHz. 3:2 is just 66% that of the front side bus, following me? Bassically what it does is allow you to run the memory slower than the CPU, allowing for higher CPU overclocks, while not taking the memory out of spec. Hope you can understand all that

jokers_greg · Feb 6, 2005

wow, a little mind boggling at first, but i think i got it. So after what I've learned:
2.4A runs at 533mhzFSB so 133mhz
my pc3200 mem runs at 200mhz
if i change the FSB setting of ma cpu to 200mhz, then I'll be running 1:1 with the memory, and the cpu will be clocked at 3.6ghz rite?

Sucka · Feb 6, 2005

jokers_greg said:
wow, a little mind boggling at first, but i think i got it. So after what I've learned:
2.4A runs at 533mhzFSB so 133mhz
my pc3200 mem runs at 200mhz
if i change the FSB setting of ma cpu to 200mhz, then I'll be running 1:1 with the memory, and the cpu will be clocked at 3.6ghz rite?

That is correct. 18 x 200 = 3600MHz. In a 1:1, your memory would be running at 2 x 200 = DDR400. Right now it's running at pc-2100 specs. 133 x 2 = DDR266

Oh, and the 533 is the overall bus speed. The FSB is the 133 number. That can confuse people sometimes.

jokers_greg · Feb 6, 2005

ok, sweet thx a lot man u really simplified this for me, and i got it now. FInally i need to ask you, will i reach 3.5, or 3.6ghz as stated in my sig with the components that i have so far?

Sucka · Feb 6, 2005

I don't know much about that motherboard. But the 2.4's can clock fairly well if they are cooled well. Also, the pressy's draw some serious power, not sure what your rails are like on that PSU, but you're gonna want 24a on the 12v line. Really depends on a lot of things, just gonna have to do some trial and error, and work off that. Good luck.

jokers_greg · Feb 6, 2005

yea, well i got 20a on the 12v rails, i hope that'll be enogh. Thanks again, i'll c just how this all works out when i get the rest of my parts

Jackyl · Feb 6, 2005

The 1:1 / 5:4 / 3:2 are actually equations.

/ = divide
* = multiply

FSB /5*4=fsbom "fsb of memory" * 2 = effective full fsb of memory.

Example. I run my p4 2.4 @ 267 FSB. and I use a 5:4 multiplyer, If I want to find out what the effective fsb of my memory is this is the equation.

267 / 5 * 4 = 213.6fsbom * 2 = 427FSB DDR or 427DDR if your posting in a thread.

Also for an intel for the full fsb it is just your fsb * 4 = effective cpu fsb.

example: 267 * 4 = 1068FSB "default is 800"

Now if you wanted to find your cpu's multiplyer take full clock speed and Devide by 4.

there are other ones but the memory one is the one that seems to be the one that most people get hung up on.

Hope this helps out a bit also

And you have a 2.4a "fsb 533" with a multiplyer of 18. So for you to hit 3.5ghz "3500mhz" you will need to get a fsb of 194 to reach that. 1:1 your memory would be 195*2=390fsb. So if you have ddr400 that should work otherwise something faster "433/466" will also work for you.

jokers_greg · Feb 6, 2005

yea, thanks that makes sense. This whole memory confusion is certainly becoming clear to me. Since we're on the topic of ratios, is there one concerning voltage that i should be informed of?

Sucka · Feb 6, 2005

jokers_greg said:
yea, thanks that makes sense. This whole memory confusion is certainly becoming clear to me. Since we're on the topic of ratios, is there one concerning voltage that i should be informed of?

What voltages are you looking for?

jokers_greg · Feb 6, 2005

oh and btw, i can see in your sig that you're doing some mad overclocking with a 2.4, is it a presscott. Can I also reach that temp wit my system? any mods i need to consider?

jokers_greg · Feb 6, 2005

oh well i was just wondering what kind of voltage i need to keep this puppy stable, and if i increase one, to what extent do i increase the other (ratio)

Sucka · Feb 6, 2005

jokers_greg said:
oh well i was just wondering what kind of voltage i need to keep this puppy stable, and if i increase one, to what extent do i increase the other (ratio)

Voltage plays no role in memory ratio per say. You might need to up the voltage to the memory in order to obtain a higher clock on it, but one doesn't play a role in the other. Your motherboard will probably be limited to around ~2.8v anyways for memory, you would need vmods or a DDR Booster in order to puch the voltage any higher.

jokers_greg · Feb 6, 2005

so if i overclocked my cpu higher (theoretically taking away heat and voltage etc.) and it wasnt stable, i could stabilize it by adding a few volts to my memory? or to the cpu itself aswell

Sucka · Feb 6, 2005

jokers_greg said:
so if i overclocked my cpu higher (theoretically taking away heat and voltage etc.) and it wasnt stable, i could stabilize it by adding a few volts to my memory? or to the cpu itself aswell

Well, the CPU would need proper vcore to be stable, which is voltage tottaly different than memory voltage. Adding vcore typically will allow for a higher CPU clock to a limit. Memory voltage will allow you to clock memory higher as well, but with the low FSB on that CPU, you're not really gonna be pushing the speeds on it.

jokers_greg · Feb 6, 2005

ok, that's alrite, i'm actually teriffied just thinking about adding voltage to any of my comp parts lol. But if anything it wouldnt hurt to adjust vcore by a fraction of a volt or a tiny percentage would it? (only ofcourse, if i need to stabilize the cpu)

Sucka · Feb 6, 2005

jokers_greg said:
ok, that's alrite, i'm actually teriffied just thinking about adding voltage to any of my comp parts lol. But if anything it wouldnt hurt to adjust vcore by a fraction of a volt or a tiny percentage would it? (only ofcourse, if i need to stabilize the cpu)

Rule of thumb is less than 1.6v actual voltage to the CPU on a Prescott. I wouldn't push it much over 1.55v actual on air though, even that's a bit high. It's not the CPU that'll give out, it's the added stress to the PSU/Motherboard that will give out first. You'll learn pretty fast that you're gonna need to up voltages to obtain higher clocks, just make sure you have the cooling to counter it. Good luck.

jokers_greg · Feb 6, 2005

Thanks man, taking your info about burning ma psu/mobo into account, I'll make sure EVERYTHING is sinked. You'll be sure to see one of my posts bragging about results if i get them lol. Thanks alot man, really appreciate your help

Sucka · Feb 6, 2005

jokers_greg said:
Thanks man, taking your info about burning ma psu/mobo into account, I'll make sure EVERYTHING is sinked. You'll be sure to see one of my posts bragging about results if i get them lol. Thanks alot man, really appreciate your help

No problem.

When can we expect to see this rig in action

Jackyl · Feb 6, 2005

My 2.4c is not a prescott.

and for ddr voltage, default is 2.6, so go up from that to get stable. and the memory divider is only needed once you cap out with 1:1 divider settings.

Memory ratio's

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