Sempron 3100+ Overclock question

By k1n9k00p4 ยท 14 replies
May 3, 2006
  1. I have these two screenshots from CPUz, one from a nornal Sempron 3100+ and an overclocked Sempron 3100+

    Standard:[​IMG] LINK:

    Overclocked:[​IMG] LINK:

    Basically my question is, looking at both screens, the only difference is a higher Voltage for the overclocked Sempron.

    So if i increased my CPU voltage to the same as the overclocked screenshot, will my CPU achive overclocked performence the same as the sempron displayed in the screenshot?

    or is there more that needs to be done to raise the clock speed from 1800mzh to 2500mhz?

    If im way off, dont flame, Im learning.

  2. eazy_duz_em

    eazy_duz_em TS Rookie Posts: 102

    well first of all..Post larger screenshots!
    The difference is the Voltage beeing raised so it can be more stable.
    Voltage does not affect Clock speed.
    It was the FSB that was modiffied.
  3. k1n9k00p4

    k1n9k00p4 TS Rookie Topic Starter Posts: 85

    ok cool, so how do i modify the FSB?

    is there software that can do this for me? or maybe do i have to do it in BIOS or on the MOBO?

    do you have a tutorial

    i dont care if i kill my system, im willing to experement.
  4. KingCody

    KingCody TS Evangelist Posts: 964   +8

    now that's what I like to hear!! :D lol

    before you do any overclocking, you need to realize that every CPU is unique and will have it's own overclock ceiling and voltage tolorance, so don't expect to get the same overclock as the the screenshot you posted above. also, you other hardware components such as your RAM chips and the mobo itself can hinder your maximum overclock.

    the external clock speed is the FSB x MULTIPLIER (which is locked at a maximum of 9). the stock settings of 200 x 9 = 1800MHz (not exact math). the overclocked settings of 280 x 9 = 2500MHz. the voltage was rasied from the stock 1.45v to 1.625v but as eazy_duz_em stated earlier the voltage didnt rasie the clock speed, it simply gave the CPU the extra juice it needed to reach its higher clock.

    that being said... to overclock your CPU, your mobo and BIOS must allow you to adjust the FSB, VCORE, and RAM divider settings. if it does then...

    1. raise the FSB in small increments (you can start off with say 220, but increase it in much smaller increments from there). each time you increase BUS speed, reboot the computer and load windows.

    2. once in windows, run some regular apps to see if the system is stable. or even better, use a stress testing program like superPI. if the system remains stable, the up the BUS a little more and repeat.

    3. once the system loses stabilty, you can try to increase the VCORE in very small increments (because overvolting is what will fry your CPU) to see if it regains stabilty.

    --also, depending on how high you overclock the BUS... you may need to use a different RAM divider to keep the RAM speed around 200MHz.
  5. KingCody

    KingCody TS Evangelist Posts: 964   +8

    so k1n9k00p4... how about an update...

    did you succeed in overclocking?

    or flrying your system? lol
  6. k1n9k00p4

    k1n9k00p4 TS Rookie Topic Starter Posts: 85

    I tried to change my FSB via BIOS settings but i couldnt find an option for it, I can change the CPU voltage though. Im currently looking for a Jetway A689DAS Mobo firmware update in the hopes that they will add the option to change the FSB.

    Does the FSB go by anything else because i might have missed it?
  7. KingCody

    KingCody TS Evangelist Posts: 964   +8

    well technically there is no FSB on an AMD64 system, it uses a hyper transport bus... many motherboards still refer to it as a FSB, but they may call it simply by "BUS" or "system BUS".

    im not sure what your mobo calls it, but it will be set to 200 or "auto"

    there should be no need to update the BIOS, if the option to change the VCORE is there, then there is definately an option to change the system BUS.
  8. tipstir

    tipstir TS Ambassador Posts: 2,699   +165

    On Sempron64 you should be able to get the same as a Sempron64 3400+ 2.4GHz Max to have the system stable most MOBO some you might an some you might be able to push more?
  9. k1n9k00p4

    k1n9k00p4 TS Rookie Topic Starter Posts: 85


    I practised my first overclock on an AMD Duron machine at work and THE CORE SPEED WENT HIGHER!!!!!!!!

    im so stoked right now lol

    The machine had a 950mhz AMD Duron . The FSB was on Jumperselect in BIOS but you can change it to 100 - 120 whatever that means.

    BUT according to CPUz the BUS speed is 200mhz but the FSB is 100mhz???? o_0

    So i tried putting it up to 120 first but the machine kept restarting on loading windows. I then put the FSB to 105, which pushed the system to 997.5mhz!!!

    Improvment of 50mhz!

    All thats left to do now is try it on my home computer ^_^

    P.S. What tests can i do to make sure that the system is stable?


    * ANOTHER EDIT: Just put the FSB to 118 (the highest i can get with out the machine restarting) and the clock speed now is 1121.1MHz!!!!

    im loving it :)
  10. KingCody

    KingCody TS Evangelist Posts: 964   +8

    With DDR, the effective BUS speed is double the actual BUS speed, which is why CPUz reports the FSB at 100 and the BUS at 200.

    With your sempron64, the actual system BUS speed is 200, and the Hyper Transport BUS is 1600.

    to raise the sempron's external clock speed uses the same process as you used with the duron. when you raise the system BUS, just multiply it by 9 to calculate your overclock. for example... raise the FSB from 200 (default) to 225, and your external clock speed will be ~2025MHz (225x9=2025)
  11. k1n9k00p4

    k1n9k00p4 TS Rookie Topic Starter Posts: 85

    Ok, ive done it with my home computer now,

    I raised the HTT to 225 and get a nice 2025mhz from 1800mhz.

    The default Vcore for my computer (1.400v) seems to be ok with the HTT at 225.

    HTT is the same as FSB though right? just different with different CPU's? (CPUz has HTT where FSB should be for my CPU)

    Anyway, what i was going to ask is - When i raise the HTT past 225 the system gets unstable and is prone to crashes, I tried raising the Vcore but not past 1.450v and the system is still unstable at that Vcore.

    What do you reccomend would be a good Vcore if i raise my HTT to 250 (Highest), How much of a jump shal i put my Vcore to?

    So, it runs 225 HTT nicely at 1.400v
    What if i raised the HTT to 250? How much do u think i would need to increase the Vcore? 1.500v? 1.600v? I want to get maximum juice out of this badboy :)

    I realise its different with different setups but i dont rly want to raise my Vcore a massive ammount yet, not without getting an estimate for the Vcore from someone who has done this before.

    AHH sry, so many questions but - "depending on how high you overclock the BUS... you may need to use a different RAM divider to keep the RAM speed around 200MHz" - So i should always try to keep the RAM speed at 200MHz?

    Just wanna say thanks man for all this great info, u have been such an awesome help. Ive learned about overclocking thanks to you!! :)

    LOL im makin a little tutorial out of the info u have given here, to help me more and my friends ^_^

    Thanks kingcody!
  12. eazy_duz_em

    eazy_duz_em TS Rookie Posts: 102

    you should lower the hyper transport to 3X for a more stable OC.
  13. k1n9k00p4

    k1n9k00p4 TS Rookie Topic Starter Posts: 85

    uh ok bit of a problem, i tried it on my brothers computer, i put the FSB form 100 to 135 and when it restarted the monitor wont come on, neither does the optical mouse light or any keyboard lights, and the HDD light at the front is constantly flashing.

    any ideas how to reslove this?, like reset it?
  14. KingCody

    KingCody TS Evangelist Posts: 964   +8

    clear the CMOS to reset the FSB back to the default value.

    if there is a CMOS CLR jumper or button, use it... otherwise disconnect power and remove the battery for about 1 minute, restart, and it shoud be fine.
  15. CrossFire851

    CrossFire851 TS Rookie Posts: 714

    I think that as long as you don't go over 1.5-1.6 volts you should be good.
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