RAM Divider. Overclocking.

[NachT]

Hi there,

I'm new to all this overclocking stuffs, just thought i'd ask a few Q's.

I'm wanting to basically run my setup faster... obviosly

So, is it right that you get a much higher preformance boost by upping the FSB rather than the clock speed?

Currently i'm running: AMD 4800. PC4000 Ballistix RAM.

FSB is 200 mhz on the CPU, and it was 200 mhz on the RAM. But i've changed the RAM divider? I think.. lol, to 250. So now my RAM is at 240mhz and the CPU is at 200 mhz. Should I not be using the divider and just clocking the overall FSB "properly" ?

I'm also wanting to lower my RAM timings, would the best way to do this just be lower by 1 digit, load windows, it's working, lower it again?


/NachT

 

[NachT]

you wuna set the divider to 1:1 then push the actual FSB up in increments of 5mhz until you lose stability or tempts get too high, you will probably also want to drop the htt multiplier from 5* to 4*

Thanks mate, i'll try to try that.

Btw is this the divider option?

If it is, how do I set it to 1:1

Yeah i'm new to this, as you can totaly tell

 

[NachT]

Well, kinda, perhaps.

S939 by default divide the HTT speed of 1000MHz by 5 to get the stock ram of 200MHz.

This is considered 1:1

166 is 5/6 of 200 therefore 166 is a 5/6 divider.

therefore if you oc the FSB to 250 and run the ram on a 166 divider you'll be running the ram at approx 208MHz (5/6)

Of course you'll need to change the HTT multi to 4 because 250x4=1000 (in spec)

Also note that there's little point in oc'ing the htt. Keep it at 1000 approx.

Google A64MemFreq11.exe for a great little tool that will work this stuff out very acurately for you.

Hope this helps

Thanks for all the info mate, it has helped.

I do have a question tho, why should I be putting my divider to 1:1 ? If I have it higher the RAM runs faster... I don't get why I should be lowering it

 

[NachT]

Being new it all sounds so complicated lol, i'll get used to it though.

Thanks for your help, i'll have a go at messing around with some settings and see what happens heh.

 

[NachT]

It sounds complicated, but its not. There's a few things you need to remember:

- Lower HT Multiplier to 4x (explained later on)
- Higher CPU FSB = Higher overclock
- Raising the CPU FSB also raises the ram speed
- From my own experience, ram doesnt like to clock as much as a CPU
- Setting the initial Ram speed lower than stock (eg: DDR400 down to DDR333) will give you extra headroom for clocking the CPU, remembering that the ram speed will increase when you increase the FSB for your CPU, so adding 40 - 50mhz to the CPU FSB will bring your ram speed back up to stock, or very close to it.

And lastly, the HT Link (as shown in the newest CPU-Z), which should always be close to 1000Mhz.

An easy way to calculate this is eg: 250(FSB) x 4(HT multi) = 1000. If you were to increase your FSB to the cpu anymore than 250mhz, you would need to drop the HT Multiplier down to 3x. Im not entirely sure why the HT Link isnt supposed to be higher than 1000, but thats what i've been told so thats what i went with.

Oh thanks, now I did understand that a bit better

I take it the HT link, HTT, HT Multiplier are all the same thing, and the HT stands for hiper transport?

Out of intrest, what FSB do you think I could reach on an S939? or is there more to it? e.i. what mobo / RAM / PSU I have effects what I can do aswell?