newbie questions about cpu overclock

Hi, first post!

I've read quite a few of the faq's and posts here and i still have a few questions about overclocking an AMD.

i have a Barton 2500+, an Asus a7n8x, and i just got two sticks of 512 Mb mushkin blue ram, stock cooling. what i would like to do is run the FSB at 200 Mhz (400Mhz DDR). i believe that i can set the multiplyer lower than the stock 11x and bump the fsb speed up to 200 Mhz and achieve a small overclock on my cpu. this is my first attempt at an overclock on the cpu and i'm kinda timid.

questions:

1. does the multiplyer and fsb speed have to equal the output of a real AMD cpu. for example: 11x x 166=1.8 Ghz (what i currently have, an amd 2500+). do i need for those numbers to equal say a 2600+.

2. if i go 200Mhz, and there is no actual 2600+ that runs a 200Mhz FSB is that a problem?

3. What will windows recognise as my processer if both questions one and two are a problem? does it even matter?

4. if i can't achieve 200Mhz, and can get somewhere between 166 and 200 do i have to set my RAM:FSB ratio to make up for running the ram under 200 Mhz?

sorry if my ignorance is glaring, but i would like to better understand before i begin.

Mucho Gonzales said:

Hi, first post!

I've read quite a few of the faq's and posts here and i still have a few questions about overclocking an AMD.

i have a Barton 2500+, an Asus a7n8x, and i just got two sticks of 512 Mb mushkin blue ram, stock cooling. what i would like to do is run the FSB at 200 Mhz (400Mhz DDR). i believe that i can set the multiplyer lower than the stock 11x and bump the fsb speed up to 200 Mhz and achieve a small overclock on my cpu. this is my first attempt at an overclock on the cpu and i'm kinda timid.

questions:

1. does the multiplyer and fsb speed have to equal the output of a real AMD cpu. for example: 11x x 166=1.8 Ghz (what i currently have, an amd 2500+). do i need for those numbers to equal say a 2600+.

2. if i go 200Mhz, and there is no actual 2600+ that runs a 200Mhz FSB is that a problem?

3. What will windows recognise as my processer if both questions one and two are a problem? does it even matter?

4. if i can't achieve 200Mhz, and can get somewhere between 166 and 200 do i have to set my RAM:FSB ratio to make up for running the ram under 200 Mhz?

sorry if my ignorance is glaring, but i would like to better understand before i begin.

Click to expand...

Welcome to the forums

Basically, for overclocking, you can IGNORE the PR rating like 2500+, 2600+, ... and the FSB rating of 133 (old CPU), 266, ....
I seldom pay attention to these two numbers.

Mainly number to look at is the ACTUAL CPU frequency and CPU FSB.

Since you have an A7N8X, if it is a rev 2.0, you should not have problem getting FSB to run at 200 MHz, provided your memory module is PC3200 (DDR 400) or better.

For AMD nforce2 board, set the RAM:FSB ratio 1:1, you get better memory bandwidth efficiency and memory bandwidth this way for a given FSB frequency.

CPU_frequency = FSB x multiplier

yes i have a rev 2.0, and 1Gb pc3200.

so what your saying is that i can run any multiplyer with the 200Mhz and be AOK, provided my cpu can handle it and pass stress tests.

i'm stoked now! thanks for the reply

get better cooling if you're gonna overclock- I recommend Thermalright and Arctic Silver 5-

alright, itshondo, you've just made me think of more questions

i'm not planning on going to big right now so i wasn't planning on getting better cooling right now, or changing the CPU voltage.

how big do you think i can go with the stock (retail) heatsink and fan? i don't want to change the voltage either. do you think i'll have to? is that just something you try after failing a stress test.

i'm supposed to stay under 60 deg C right (i believe i've read that somewhere in these forums)?

I suggest you to use the stock heat sink and fan to get the whole thing running stably first, to get use to the working first, ... then go from there.

For stock heat sink and fan, with ambient temperature around 20 - 30 C (summer is coming), one should be able to get 2.1-2.2 GHz out of it.

With a good copper HS such as SLK-947/SP-97 and a high speed adjustable fan such as Thermaltake Smart Fan II, one would expect to get around 2.3-2.4 GHz from a desktop barton, and 2.4 - 2.6 GHz out of a mobile barton. (I don't know whether your barton is unlocked desktop or mobile).

Generally, most people would put a fix number of max temperature, say 60 C or 55 C or 50 C on the CPU, it is fine as a first order guideline.

Technically, CPU temperature and CPU stable frequency vary inversely, higher frequency requires lower temperature and vice versa.

E.g.
- A CPU can run stably at a much higher temperature (e.g. 60+ C), at a lower Vcore and lower frequency (e.g. 1.4 - 1.6 V, 2.2 - 2.3 GHz for Tbred B/Barton) than its intrinsic ideal max frequency.

- A CPU needs a much lower temperature (e.g. under 30 - 45 C on air or even lower for extreme cooling) to run stably at high Vcore for sustaining a higher overclocking frequency (e.g. 1.8 - 2.0+ V, 2.5 - 3.0+ GHz).


For technical details:

Originally posted by hitechjb1
...
The higher the voltage and frequency, the higher the power and the higher the temperature. Such active power will increase the CPU to certain temperature under certain load for a given cooling.

Since carrier mobility decreases as temperature increase beyond certain temperature due to lattice scattering, transistor switching slow down as temperature increases. So the frequency f of a CPU varies inversely with the temperature, or df / f = - k dt, mathematically.

The balancing of these two opposing actions, or the intersection of the voltage-frequency curve and the temperature-frequency curve of a CPU characteristic naturally determines the final stable voltage/frequency/temperature operating point. If overclocking is done properly, the maximal overclocking should settle naturally at certain frequency, voltage and temperature, as desribed above, below the maximum absolute rating of voltage and temperature (as seen from Tbred/Barton, ...). A perceived stable voltage and temperature setting may not be necessary after all, if the voltage, temperature, frequency variations are monitored properly.

CPU voltage: from stock to max absolute, from efficient overclocking to diminishing return (page 19)

Click to expand...

i read thru quite a bit of that stuff and it does make sense to me.

there's so much information in that link...and it links me to more info on other links...i've got a lot of stuff to read.

i don't get my new ram for a few days so i've got a little time to completely understand it all. i'm sure i'll be back with more questions.

thanks for the help! it is much appreciated.