Fsb, Ltd/fsb, Cpu/fsb Oh My!

[Hoody]

I have been lurking here for about a week now. I have also printed and read the 42-page guide.

 

I understand that in order to reach optimal overclocks I need to push the CPU to it's max first while clocking down my RAM; then vice versa.

 

My question is...I guess I don't seem to understand which BIOS setting clocks UP the CPU and DOWN the RAM.

 

The settings I 'think' I should be using are:

 

FSB Bus Freq (Default 200 MHz)

LTD/FSB Freq Ratio (Default AUTO)

CPU/FSB Freq Ratio (x10)

 

Which do I crank up and which do I crank down?

[Mochaboy]

http://dfi-street.com/forum/showpost.php?p...179&postcount=4

 

The settings you need are in the genie bios menu

[Hoody]

so the settings I am inquiring about ARE from the Genie BIOS menu. The link you attached is all about the RAM timings and such, I didn't see anything about the CPU in that post.

 

so am I supposed to NOT touch:

 

FSB Bus Freq

LTD/FSB Freq Ratio

CPU/FSB Freq Ratio

 

...and only adjust the RAM timing from the post you linked to?

 

Are the Genie BIOS settings different in the non-Expert boards?

[Mochaboy]

I apologize, I misread your post...

 

This explains how set the CPU clocks up or down

http://www.dfi-street.com/forum/showpost.p...167&postcount=3

 

Memory settings are in the link provided in my first post.

 

In BIOS - Genie Bios settings - the first menu you get gives you the options to clock the cpu, there's also a sub menu of this screen for DRAM configuration where you configure the settings for your memory.

[rldolph79]

You might be in over your head here...but if you need more info try searching some more. The answer to your question is on this site, you're just going to have to find it. If you need some help with your search there's a sticky on searching that you should find helpful.

[madian225]

Hi

 

Firstly you will need to know what the max multi is for your CPU ( I think that it may be 10 but please double check)

 

If it is indeed 10 ( I repeat IF) then set your CPU/FSB to this figure what ever it may be.

 

Stage 2

 

Lower the LDT/FSB Frequency ratio to 2.5 or 3

 

Stage 3

 

Set your RAM Ratio from 200 1:1 to 100(Mhz) 1:02 - (DRAM Frequency - it is located at the top of all your memory timing in the BIOS)

 

Stage 4

 

Decide what voltage you wish to use for the CPU ... this part is all about personal preference and what YOU are happy with. I would use the SiSoftware Sandra to 'burn test' your CPU at the different voltages to see what kind of temps you are reaching.

 

For information I started out at 1.3 v and ended up at 1.475 V for the CPU, this gave me a max system temp of 40 (50 according to Sisoft) and as I am running on water this was about the max that I was happy to go to.

 

I would suggest starting low and gradually working up bit by bit and see where you go.

 

Stage 5

 

OK your CPU speed should still be at the original 200 and your CPU multi should now be on your default max Multi 10 or 11 or 12 what ever YOUR CPU's max is.

 

Stage 6

 

Increase the CPU speed from 200 in 10-15 mhz increments, each time boot into windows, run Super Pi 32M test which will take 40 mins or so......if it passes then go back and raise the CPU speed a further 10-15 mhz...getting the idea ?

 

Now keep going until Super Pi gives you an error...drop that speed down 2 then try again...still an error...a further 2 etc... until Super Pi passes again.

 

Now you should have ROUGHLY the max speed your CPU will do for that voltage .....say it max's at 225 then your max CPU speed COULD be 225 * (CPU Multi..say 10) = 2250 Mhz

 

If you increase the voltage to the CPU then in turn you will raise the max CPU speed BUT KEEP A CLOSE EYE ON CPU TEMP'S. I would recommend running the SiSoft each time you find the CPU max at each voltage so you can see if you are happy or not.

 

I would not suggest going much above 1.5 V but the final choice is, as always yours, and if you do go to high then.......scratch one CPU after a period of time.

 

Other forum members have gone quite high and it all comes down to personal preference about YOU really want from your PC, a high O/C and stable is everyone's aim but also being realistic will help a great deal. I am running at 4800+ dual core on water and I have gone from 2.4 to 2.64 and cannot go any higher so for yours I would say a 10% increase in speed will probably be close to your max.

 

So you know know your max CPU speed ..say 2250 ( 225*10). However, if you lower your CPU multi to 9 ......2250 / 9 will increase your FSB to 250 instead of the 225 that you had before BUT you have lost out on the CPU speed. Again it is up to you what you want the most but test test test and then tests again with different CPU multi's to see what suits you best.

 

OBVIOUSLY, any final CPU speed need to be Prime 95 stable for at least 18 hours, you may well find that it will pass Super Pi at 225 * 10 but will fail Prime 95, you will therefore need to lower the speed down a few more 223 etc. until Prime 95 does pass for 18 hours. It will be at this point that you will 100% be certain of the final CPU max speed.

 

With this in mind re-read the wonderful AMD overclocking guide again.

 

I would not worry too much about your RAM at this point in time lets get the CPU max speed finalised at the max voltage that you are happy with. Until then anything else needs to be put on hold.

 

I hope this helps and again BECAREFUL of your CPU temps AT ALL TIMES, and with O/C'ing comes risk and accept that if you go to far the only person to balme is YOURSELF.

 

I hope this helps you understand it all a bit more, take 1 step at a time and you will be fine, this forum has loads of experience people all of whom are more than willing to help. read the O/C guide and if in doubt just keep asking. You WILL get there trust me, if I can do it so can you. It will take time and patience and if you have those 2 then your system will rock.

[Hoody]

[Edit: Madian225, thanks! I was mid-post when you submitted your thoughts]

 

[Edit#2: ok, so I didn't know about the DRAM reduction...Step #3...thanks!!!]

 

Mochaboy, thank you.

 

So I think I understand it now.

 

so to kick up my CPU I will increase the FSB and/or CPU/FSB ratio

 

and to downlock the RAM I decrease the LTD/FSB ratio

 

so I could start with something similar to:

 

FSB bus freq = 220

CPU/FSB ratio = 10

[sets the CPU to 2200MHz]

LTD/FSB ratio x3

[sets the FSB/HTT to 1320 (660x2)]

 

..and keep kicking up the FSB bus until it becomes unstable

 

another question, in what scenario would I want to bring down the multiplier from 10? Is keeping it at 10 and playing with the FSB bus the way to go?

[madian225]

Hi

 

Basically yes, make sure that you reduce your DRAM frequency first to ensure that the RAM does not hold the CPU back which changing it from 200 1: 1 to 100 1: 02 will achieve.

 

Kepping the LTD/FSB to 3 will enable to you to reach a max RAM speed of 333 (333*3 )*2 = 1998 which is just under the 2000 limit. Unless you find that your CPU is a serious O/C'er or you lower your CPU to a very low multi I very much doubt that you will achive a speed of 333 on the FSB with a final RAM ration of 1:1.

 

I would initially keep in on 10 until you find the guaranteed 100% stable max speed. do some test's get your results and see where you are at, then you can try lowering it to 9 do more tests and see.

 

The fun will really begin when you test the RAM and then add the two together !! but that is for another day. Find the max speed that is 18 hour minimum Prime 95 stable first.

[Hoody]

Thank you soooo much guys. I'm off to OC...will post back with results.

[RGone]

Well a jump to 220FSB on that memory may be a foolhardy too much jump. Here is link to entry in the overclocking data base with ALL the information about the timings and voltages and all that were used.

Post by Spirit...

 

Here is one more OCDB entry. By Angry_Games...

 

You can see how 'high' the pushed their FSB on their memory and were still able to get all the benches done and stable as well. Pushing too far can corrupt the O/s and ruin your day. Most of us have been there and done that multitudes of times. And with any configuration of parts different one from another > YMMV considerable.

 

RGone...

 

Thank you soooo much guys. I'm off to OC...will post back with results.

[Hoody]

Well a jump to 220FSB on that memory may be a foolhardy too much jump. Here is link to entry in the overclocking data base with ALL the information about the timings and voltages and all that were used.

Post by Spirit...

 

RGone...

 

true true...my 'OC ignorant' thinking was based on seeing other posts with x2 3800 owners easily getting 2400MHz with no voltage increase and stock air...so I thought 2200 was conservative.

 

but your point is well taken, and I will reserach further before deciding on my starting point.

[ooztuncer]

dont forget to play with cpu voltage (highly likely you have to increase it, and use search button to find ur safe voltage setting) and don't forget to monitor the temps while testing (smart guardian / mobo monitor should be OK).

 

have fun...

 

EDIT: sorry, if my post was kinda reiteration of madian225's post - but these are the most important factors imo.