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Overclocking guide for newbies here...

Discussion in 'OC Archive' started by NF7-S, Oct 29, 2003.

  1. mrthingyx

    Man of Honour

    Joined: Apr 3, 2003

    Posts: 15,183

    Location: Cambridge

    For DRAM ratios and whatnot - there is another thread on that... look for y2viks.

    As to the effect of FSB on Athlon XPs, here's my take.

    Using an XP2400 on an NF7 v2, with timings at 2-2-2-11 on WinXP; benched with Aquamark, Sandra 2k4 and Pifast. The unbuffered memory bench in Sandra can be activated when looking at the 'options' tick-box screen (the icon on the bottom left when bringing the benchmark screen up).

    The Athlon XP was benched at 133x15, 166x12 and 200x10 to investigate the effects of increased CPU and system bandwidth on everyday performance.

    Aquamark first.


    It would appear that - despite the silly scale on the graph - front side bus rate does have an effect on the CPU's athleticism... albeit rather small.

    PiFast next...


    PiFast appears to rely on system bandwidth more heavily than Aquamark (perhaps Aquamark is more GFX dependent?) with reductions of over five seconds just by increasing the front side bus - remember, the CPU clock rate has not changed (ok, fine - it's 1992MHz or whatever... the BIOS picks it out as 2GHz).

    Let's see what Sandra has to say for herself...


    Oooh... do I detect a decrease in useable memory bandwidth? As can be seen, decreasing the FSB of the CPU reduces the amount of data it gets to allocate to the RAM meaning the CPU is sitting, twiddling its thumbs waiting for the RAM to catch up.

    Despite all the CPU clocks being (effectively) the same, there is obviously extra peformance to be had by increasing the front side bus of the processor. This is especially pertinent for those of you playing with locked multipliers - you see? All is not lost! Concerning the PiFast results, too - although there is only a very small drop in Aquamark performance with decreasing FSB, PiFast is raw calculation, meaning that DivX-ing (for whatever reason) and mp3-ing will be faster the more FSB (memory and system bandwidth) you have.

    The moral of the story? Reduce that multiplier and ramp up the FSB for a better wired life.
  2. Chong Warrior


    Joined: Oct 18, 2002

    Posts: 12,044

    Location: Manchester

    No, it wasn't / isn't very clear.

    It's very hard to get your point across when you need to start going on about things like this. You should try writing a guide!:eek:
    The actual writing isn't hard, it's wording it so you really think a n00bie will understand it when reading through it for first time.

    From what I can gather you're getting at. You asked this:-

    Is there any difference between (say):

    200fsb x 10 (2000Mhz), and mem at 6/5 (333Mhz)


    166fsb x 12 (2000Mhz), and mem at 6/6 (333Mhz)

    Probably not, no. Why?

    Because you'd be running your CPU and RAM "out of sync" i.e. not at the same speed with the fsb at 200, thus taking away all the advantage of having a faster fsb in the first place. Your CPU has 400fsb but your RAM only has 333fsb.

    Same as running 5/6, your CPU only has 333fsb but your RAM has 400fsb. Do you see? you need both to run either 333fsb or 400fsb or " in sync " for optimum performance. Otherwise the faster one has to wait for the slower one, bringing buffers into play, which slow things down even more.


    200fsb x 10 (2000Mhz), and mem at 6/6 (400Mhz)

    Would be the optimum setting because the CPU and RAM would be working at the same speed. To try and make it even more clear

    222fsb x 9 (2000mhz), and mem at 6/6 (444mhz)

    would be even faster. Even though the CPU is still at 2ghz, it's internal clock is running 10% faster, as is the RAM.

    Also on a side note and without trying to confuse things:-

    166fsb x 12 (2000Mhz), and mem at 6/6 (333Mhz) should be run at

    166fsb x 12 (2000Mhz), and mem at 5/5 (333Mhz), ideally

    RAM and CPU should have these dividers with these fsb speeds.

    6/6 = 200fsb and over
    5/5 = 166fsb and over
    4/4 = 133fsb and over
    3/3 = 100fsb and over

    Though it isn'y really that important as long as both numbers are the same so essentially 1/1.


    I should make more obvious here, all my advice is for AMD systems. Pentium are different as they have a lot more bandwidth to play with than AMD.

    Just had a look at the thread that's linked below and that's a very good thread and more aimed at the Pentium side of things.
    Last edited: Feb 24, 2004
  3. mrthingyx

    Man of Honour

    Joined: Apr 3, 2003

    Posts: 15,183

    Location: Cambridge

  4. SteveP


    Joined: Apr 2, 2003

    Posts: 76

    ok, thanks guys. I think you've helped me understand a little. Basically, as has been said, the rule of thumb is to have the fsb as high as possible for maximum benefit, although, if I understand this correctly, this is possibly an upshot of the fact that the 3/3 4/4 5/5 6/6 ratios are the best for synchronisation purposes, and having a non maximised fsb means that the memory isn't running at it's optimum speed.

    mrthingyx's graphs are interesting - but he doesn't say whether the SDRAM ratios are being altered or not. If they aren't then presumably, it's just the difference in fsb that is being measured.

    The thing that puzzles me is that this advice is contrary to the results I've seen myself in Sandra in the very little amount of testing I've done, but I wonder whether this is due to having DR333 ram...

    200fsb x 10 (2Ghz) - CPU 7329/2997 Mem 2270/2063
    166fsb x 12 (2Ghz) - CPU 7412/2997 Mem 2373/2231

    For these tests I had the ratio on auto, so the memory was running at 333Mhz both times - is the lower score at 200fsb due to the synchronisation issue in that the memory isn't synched up with the fsb?


  5. Broken Hope


    Joined: Jan 16, 2003

    Posts: 8,511

    Location: Nottingham

    If you're using an NF7 then auto is exactly the same as 1/1 2/2 3/3 4/4 5/5 or 6/6 it keeps it in sync with the FSB.
  6. TheTross


    Joined: Jan 13, 2004

    Posts: 2,608

    Location: Market Deeping

    Bumpity bump:)
  7. Hi all, thought I'd place my first post here, been having problems OCing my system, and I'm new to OCing.

    First up my system

    AMD 2400XP+ Tbred
    EPoX 8RDA+
    512 DDR PC2100
    ATI 9600XT (not overclocked, but using latest omega drivers)
    Audigy 2
    60gb Seagate HD, and a 120gb Seagate disk (8mb cache version)
    Mitsumi CD-RW
    Panasonic Slot in DVD drive
    XP Pro

    I noticed the CPU database thread, and had a look in there to see what is sort of an average increase for my system would be, and noticed that a fair few people had got their system running with at 200x11.5 (2300mhz, a 300mhz increase), so i thought i'd give it a go. However I have run into a number of problems....

    Firstly I set the bios settings to optimal, and the set the cpu at 200x11.5, but the system locks up on the restart, and won't go to POST. Not sure why this is though.
    It POST's fine using 200X11 (2200mhz), but then i get another problem, in that windows won't boot, apparently because a krnl file is corrupt..... If i reset the CMOS, and set everything back to optimal (using stock speed) it boots up into XP fine.

    I have left the memory timings at optimal (6,3,3) when trying the OC, but I'm wondering if the fact that the memoray is PC2100 is holding me back? Admitadly I haven't touched the voltages though, would that help?

    So am i doing something wrong? or do i need to update the bios ?(I have tried epox magic flash utility, but it says the bios is up to date)
    And what can i do about the windows thing?

    Any help would be appreciated.

    cheers in advance
    Last edited by a moderator: Mar 16, 2004
  8. Dataisgod


    Joined: Oct 24, 2003

    Posts: 245

    Location: Ireland

    a couple of things are probably causing problems here. for a start you have 2100 ram which is probalby designed to run at 133mhz or something i can't remember the exact frequency while you are trying to run it at 200mhz by setting it to 200*11.

    to start your overclock i would just try increasing the multiplier. for examples if your chip has a fsb of 133 *16 or what ever just try increasing the 16 to 16.5, 17.

    second thing is you may not be able to just increase you frequency like that without increase the voltage running through the cpu. so it ifs at 1.75v try 1.80v or 1.85v. but don't go nuts increasing the voltage to get stability. increased voltage brings increased temperatures and that is bad. i don't know what coolingy you are using but try to keep the load temp below 50c.

    and just follow the very good guide done above by nf7.

  9. cheers for the quick reply, guess I'll try fiddling with the multiplier and voltages tonight.
    I think i have a better understanding now. If I want to run the fsb at 200 i need memorary to support it, like 3200? I take it 2700 won't run to that speed?
    now how much cash have i got in the bank, might need to spend a bit on better mem....
    Last edited by a moderator: Mar 16, 2004
  10. NF7-S


    Joined: Oct 25, 2003

    Posts: 5,722

    Hi guys, glad people are still using/lovin this :eek:

    might need this tread myself soon as I'm building a PC for a mate...keep up the good work, great to see so many helping out and adding to it :)
  11. NickK


    Joined: Jan 13, 2003

    Posts: 17,947

    I'd also add to the "things to know" is that it's entirely possible to corrupt your harddrive or loose the data on that drive.

    True - this is minimised by PCI locks for those HD controllers that sit on the PCI bus.. but that written data will be processed by a possibly unstable CPU, maintained in possibly unstable memory etc..

    Just add that all important data should be backed up.

    In addition it may be useful to show a diagram of how the current non AMD64 based chips fit together.
    Last edited: Mar 16, 2004
  12. well i tried upping the multiplier last night, but my system became pretty unstable. I think I'm gonna have to invest in new ram if i want more performance.... :(
    thanks for the guide

    EDIT - Balls I forgot about voltage settings, I'll try that before buying new ram yet....
  13. neoboy


    Joined: Mar 16, 2004

    Posts: 11,596

    Location: UK

    Just want to ask if this fan any good:
    Thermaltake Silent Boost!!

    Links to competitors are not permitted on these forums, please read the rules before posting again!
  14. Psycrow


    Joined: Jan 16, 2003

    Posts: 4,948

    Location: Kirkcaldy, Scotland

    If you changed the multiplier it has no effect on the ram, it only increases the cpu speed. Chances are more that you needed some more voltage.
  15. Can't get 200mhz Out of NF7Sv2

    Great giud by the way - really helped the virgin overclocker that I am.
    I can here your si's already - here me out.

    I have NF7Sv2 with the infamous barton 2500 XP.
    My DDR RAM is 2x512 pc3200 running in dimm 1 & 3 to get dual band. See I'm learning, I'm learning :>)

    The ram is from PC world and is nothing special.

    My problem is, I can't get the CPU from 166 to 200. It will clock to 2.2Gigs using the multiplyer, but reading the forums here, Is it better to raise the CPU speed rather than the multiplyer. This I cannot do!?!?

    Is my problem the memory?? Help

    Also, your brilliant guide also states I should be looking my AGP bus speeds and PCI ratios at 1:1 - how do I do that.

    My board is supposed to be one of the best for all this fiddling. Although If I break our PC the wifes gonna kill me :>)

    any help would be much appreciated

    many thanks thanks in advance

  16. NF7-S


    Joined: Oct 25, 2003

    Posts: 5,722

    locking the agp is like I said - look for an option (think it's on the first bios screen - it's the screen that also shows what speed the CPU is running at) that gives an option to set it to 1/1.

    the RAM might be the problem, but you shouldn't be messing with the FSB BEFORE locking the AGP (I thought u said u read the guide??)!
  17. Overclocking help

    yeah, yeah. Did read the guide my man.

    I will take a look at my bios though tonight.

    Forgot to mention that, it clocks to 200 fine using single stick of ram.

    I've also got CPUZ and it say I'm running 1:1 ratios

    presuming this is fine, can you offer any further advice as to what might be the problem when using 2x 512 at dual channel.

    many thanks again matey


  18. 2600+ Barton with a coolmaster jet7
    512 of pc3200
    MB MSI K7N2 Delta "good board"
    the system is stable @ fsb 195 * 11.5 2.24ghz
    max 45c prime95
    idle 37-38
    once I get the other 512 pc3200 and get the dual channel running I'm hoping it will go well into the 200's.

    Whats the best I can hope to get from the Barton 2600?
    Last edited by a moderator: Mar 20, 2004
  19. Chong Warrior


    Joined: Oct 18, 2002

    Posts: 12,044

    Location: Manchester

    Re: Overclocking help

    You've got the NF7-S v2.0 right? cool.

    No need to worry about the AGP and PCI speeds, they're locked automatically;)

    To get your PC to 11x200 I'd suggest going into the BIOS and in the same menu where you adjust the speed of your CPU you'll see options about voltages underneath.

    Change the top option to manual, this will allow you to change the volt's for for CPU (1.65v default), northbridge (1.6v default), RAM (2.6v - 2.7v default) and AGP (1.5v default ).

    Change your CPU voltage upto 1.675v or 1.7v just to be sure of 100% stabiltiy.
    Change the northbridge upto 1.7v (which is the maximum you can set it to )
    Change your RAM up from whatever it is by 0.1v (so if it's at 2.6v change it to 2.7v )

    Try that, if it doesn't work, post back here;)

    Also change the CPU / DDR RAM ratio to the 6/6 divider.
  20. Hi there, first post so be gentle. :)

    I`m looking at assembling a new computer almost purely for SETI, Find-a-Drug type work - ie no real graphics just processor power.

    Is there any advantage to buying a 2.8 Barton over a 2.5 or 2.6 Barton or do they all clock up the same please? Or is it even better to go for Thoroughbred etc? there is only about £20 difference between 2.5 and 2.8 anyway so if the 2.8 will be more stable, easier to clock etc i`d go for that, but if 2.5`s can achieve better speeds i`ll go for that etc...

    Any suggestions appreciated.