need overclocking advice (amd64)

Discussion in 'Benchmarks & Performance' started by epk, Jan 17, 2007.

  1. epk

    epk Moderator Political User Folding Team

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    i was thinking on maybe overclocking my cpu (3200+ venice) a little -nothing major, no voltage increments or anything like that-... the thing is, i've been reading different sites and there's one thing i don't seem to get

    i read somewhere that every mhz you add to the htt bus gets also added to the memory clock speed... well, i was planning something like getting the htt up a little, change the ht multiplier to 4 and lower the ram to 166 (it's a kingston value ram ddr400)
    however if i do this the ram clock is gonna be slower than the htt... is this gonna cripple my performance? (as ram bottlenecking the rest of the system?)
    also, could this be solved with dual channel ram?

    oh... and if anyone knows... how much real perf difference is there between running the fsb/ram in syncrhonous mode and asyncrhonous?
     
  2. LeeJend

    LeeJend Moderator

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    It's not worth overclocking a little unless you can push the FSB (HTT) and the RAM both. What you gian on clock cycles you loose on missed cycles because you are not running synchronously.

    If you want to overclock you need a MB that lets you set CPU clock, PCI clock and ram speeds independently and at 1 mhz steps. Running your PCI or AGP slots overclocked can fry your add in cards. Be careful.

    Unless you have an Opteron the AMD chips do not allow you to change the multiplier which is the desired method of overclocking. That just leaves changing the base clock speed.

    I run my system 5% over clocked on CPU and RAM using crucial DDR 400 ram just because I can, the speed improvement is negligible. If your ram can't handle the higher clock speed retard the ram timing settings a little and see if it supports the higher clock speed then. It's better to run with relaxed timing and synchronous RAM and CPU.

    Make sur to watch your CPU and MB temperatures while overclocking. Run a burn in check with sisoft sandra lite to monitor temperatures under load for at least 30 minutes before leaving the system unattended.
     
  3. epk

    epk Moderator Political User Folding Team

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    you think i could push the ram at least a little bit? it's value ram... branded though

    i don't wanna raise voltages so if i buy oc friendly ram it would probably go to waste

    btw, when i said i didnt want to make a big overclock, i was mainly referring to not touching the voltage... but i still could hit 20-25% (i know a lot of people with this cpu-core could get to 35% with stock fan/volt)
     
  4. LeeJend

    LeeJend Moderator

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    ddr400 ram is pretty good these days, even the value lines. I would expect the ram to go to 420 even without relaxing the timing. Relax the timing and it might make 440.

    That lets you synchronously up the system speed by 5% maybe 10%, though 10% might be an issue with the chipset.
     
    mlakrid and epk like this.
  5. epk

    epk Moderator Political User Folding Team

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    thanks
     
  6. mlakrid

    mlakrid OSNN BASSMASTER Political User Folding Team

    YOU GO LEEJEND!

    Very nice, the only thing I would point out is taht the cycles dont have to be changed by 1Mhz steps, so long as everything remains stable, what do you care what the difference in step size is? :eek: ALthough I will admit it will make it that much easier to do, however!

    I would venture to say you can get a 10% total system OC, although you may need to add more system fans, as a general rule I tell all my friends to ensure they have enough of an air flow to be able to tell the difference in temps between the intake and exhaust of the machine, which also means making sure the seals for yur case are set properly so as not to have dust enter through cracks, and to ensure airflow across the most sensitive areas of your PC: CPU/GPU, normally I would also say north and/or southbridges, but the architecture is different, dont they share one for both or something like that?

    Anyway hope what LeeJend already said... Reps+ LeeJend!
     
  7. epk

    epk Moderator Political User Folding Team

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    i was mainly concerned about how much i could push the ram
    the 3200+ venice core is really great for o'c... at stock speed, stock fan (with 2 case fans) and 100% utilization doesn't reach more than 34°C... and is summer here!
     
  8. LeeJend

    LeeJend Moderator

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    mlarkid - my bad I was thinking 1% which is more like 4 mHz, not 1 mHz steps. 5% steps like the cheaper MB's support (i.e. mine) is a little too coarse an adjustment.

    epk - if your ram resists 10% overclcocking try relaxing the settings from 7.5 3 3 2.5 to 8 3 3 3 or 8.5 3 3 2.5 your speed will not suffer much and the ram may accept the higher synchronous clock which is what you are really after. The 533 mhz DDR2 uses timings like 12 4 4 4 to compensate for the higher clock speeds DDR2 supports.
     
  9. epk

    epk Moderator Political User Folding Team

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    thx... i didn't know that

    btw.. you know how much the htt bus can be pushed? i've heard that not too much, but i've been wondering if at least 10% is possible
     
  10. LeeJend

    LeeJend Moderator

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    I've been running mine at +5% for 18 months. It was so long ago I'm not positive but I think my video card was the weak link. My MB did not support independent clock speed controls.

    How much you can push will depend on what speed and model CPU you have. If it's already top end don't expect much. If it's a slower processor then it may have more headroom.

    http://www.c627627.com/AMD/Athlon64/

    Venice, San Diego for single core and all the dual core chips are more suited for overclocking because of improved copper interconnects.

    Download CPUz.exe for everything you ever wanted to know about your RAM and CPU hardware.

    PS Safety warning
    As long as you watch your CPU and System temps damage is unlikely with newer model systems. You do want to be careful of HD corruption so back up your data before starting. Use of a software based overclock tool is best if your MB has one. If the system crashes it just reboots to your bios settings.

    If you overclock in bios before you know your limits you may need to do a CMOS reset to recover the system. There used to be a problem with accidentally wiping the BIOS during CMOS resets. Some manufacturers have fixed this but follow this closely if a CMOS reset is required:
    Turn off the system and unplug the power supply. Wait 3-5 minutes for all internal energy to bleed off. Then do the CMOS reset. I know of 3 people who lost their MBs by not following this procedure.
     
    Last edited: Jan 20, 2007
  11. Bman

    Bman OSNN Veteran Original

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    the link you posted is only an image of the speeds of the cpus, doesn't exactly help me out.

    Where do I download that cpu.exe file or whatnot.

    So your saying the newer the cpu the less overclocking ability it has? I don't really understand that, shouldn't I be able to overclock a crap more.
     
  12. LeeJend

    LeeJend Moderator

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    majorgeeks.com has it.

    Yeah the link was just a list of the various cores, their names and speed ranges. It will give you an idea of what each core type does once you find out what yours is with CPUz.


    Umm, you might want to catch the last few posts in this thread before you start overclocking too much...

    http://forum.osnn.net/showthread.php?p=775193#post775193