CPU speed/RAM timing question.

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Syrillian

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Hi,

Which of the following sets of speeds would be faster for gaming?

I am fairly new to overclocking and would like some input please...

1) CPU @ 2.2GHz / RAM @ 220MHz (3-3-3-8)

2) CPU @ 2.4GHz / RAM @ 166MHz (2.5-3-3-7)

CPU = AMD Athlon FX x2 3800+
RAM = 2 x 1GB Corsair ValueRAM

There are only 2 sets of speeds (listed above) shown under the "SPD" tab of CPU-Z

Also, what is the RAM divider, specifically where can I view the information and where can I alter it? In the BIOS only?

Motherboard = ASUS A8N32SLI-Deluxe

Thanks for your time.
 
The best is the first one. In the second your RAM is underclocked (even though the timings are slightly tighter), which isn't a good thing. A RAM divider is used in overclocking. When raising the FSB on the CPU to overclock it, it also overclocks the RAM. If your RAM isn't stable with the overclock, you have to use a RAM divider. It's basically a ratio that makes the RAM clock speed increase more slowly as you raise the FSB. That way you can raise the FSB, but lower your RAM's clock speed so your RAM won't limit the overclock.

If you put a divider on the RAM, it will downclock the RAM. But as you continue to overclock your CPU, it will bring it back up to it's normal speed. Sometimes you will overclock the CPU enough to where the RAM becomes a bottleneck again, which means you have to either put a larger divider on it or stop overclocking. Understand now?
 
Go with number 1.



A divider is basically the ratio of FSB speed to Ram speed, so when its set to stock settings its at 1:1, with FSB at 200 and memory at 200mhz - effectively DDR400.


example. I have a opty 175. Its multiplyer is stock a 11.

So if you set your divider to 1/2, which forces your ram speed to 1/2 of your FSB, so at stock speeds your cpu would still be 200x11, but your ram would be 100, or DDR200.



Dividers are OC best freind somtimes :D


for instance when they want to find there max cpu they use dividers. so It takes the memory out of the equation,that way when you're running prime95 or superpi, you don't have to worry about your ram generating errors that could potentially reduce your theoretical max overclock.


Now when finding the max of your ram, you want to keep the divider set to 1:1, and reduce your muliplier so your cpu runs below spec while ram runs above spec, and do the same thing basically.


Now when you have the max stable frequencies of both, you need to add them together. If your max cpu frequency is 2700 and max ram is 270, thats easy. Keep it 1:1 and set it 270x10. Usually you won't get lucky like that, but choose the best divider you can. Always max out your cpu speed though, as memory speed gives minimal benefits.
 
Thanks to NathanM and Lord AnthraX,

Concise, and simply put for the layman.

If I am interpreting correctly I should be able to take my CPU to faster speeds.

What I am currently running:

CPU = 2.2GHz
RAM = 220MHz (3-3-3-8)

What I am after is:

CPU = 2.4GHZ
RAM = 220MHz @ 3-3-3-8

-or perhaps some equivelant that is faster than my current settings

In order for these numbers to be achieved and remain stable, what would I set the RAM divider to? In this case it seems that it would be a fraction with a decimal number (i.e. 1/1.25).

Is my interpretation accurate? If so what RAM divider would I usem and where can I change it?

Thanks...
 
No you couldnt do that.

Ok lets say your max cpu is 2.8 But your ram maxes out at 250 with your multi at 12.


12 x 250 = 3000 MHz and that wont work obviously, becuase your max is 2.8

11 x 250 = 2750 Mhz That will work but your not getting your complete max cpu.

12 x = 2796 This is as close as you can probably get.


Remember always sacrafice ram speed for CPU speed.

Straigh outta the book :D
 
Thanks to Lord AnthraX!

Would you spare some more thoughts?

BIOS options:

Max Multiplier = 10
Max RAM speed = 250

Would I be able to run this?

Cpu = 9.5 x 250
Ram = 250 (3-3-3-8)

I dont know if the RAM timings are feasable, what's the correlation between increased RAM speed and RAM timing?

I can raise voltages on the CPU (already @ vCore 1.42 ) and on the RAM to keep the system stable...... should I?

Do you think that the Corsair ValueRAM could handle the speed and load? Is it time for some XMS...?

Thanks for all the info you have already provided.
 
you seem to be missing the point of the #spd tables, they are only so that a motheboard can default to those settings or to provide you with an idea of what the memory is capable of. as suggested you should always sacrifice memory speed for cpu speed if necessary, kept within reason of course. it woul be ridiculous to be running your ram underclocked by 100mhz for example. i would always try and keep the ram above 166mhz (DDR333). overclocking is all about trial and error, any guide will tell you that. simply keep trying different combinations (and testing them) until you find the optimum overclock for both. just don't do anything stupid like massively overvolting your cpu ;)
 
nitestick said:
you seem to be missing the point of the #spd tables, they are only so that a motheboard can default to those settings or to provide you with an idea of what the memory is capable of. as suggested you should always sacrifice memory speed for cpu speed if necessary, kept within reason of course. it woul be ridiculous to be running your ram underclocked by 100mhz for example. i would always try and keep the ram above 166mhz (DDR333). overclocking is all about trial and error, any guide will tell you that. simply keep trying different combinations (and testing them) until you find the optimum overclock for both. just don't do anything stupid like massively overvolting your cpu ;)


correct :)


And a note to Syrillian remember, Overclocking dosent happen over night and that even the best OC'ers face problems. It Takes time, and like nitestick said, trial and error.
 
Thanks nitestick and Lord AnthraX,

I have been experimenting and the running 3dMark06. So far the best that I can come up with is:

CPU = 2.33GHz
RAM = 194MHz

These settings boosted the 3DMark06 up by 60 points and increased the FPS in F.E.A.R. to 49 average, and HL2 E1 to 68 average. I'll just keep twiddling with it.....

Thanks for all your input and help!
 
See if you can get your ram past 200MHz. Play around with voltages and stuff and you'll probably get there soon. If you can raise the HTT (FSB) 54 in total your ram will be running at 220MHz. Aim for that.
 
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