TechSpot

overclocked AGP bus

By Niatross
Feb 20, 2002
  1. Tell me if you think I'm right. I can overclock the FSB to where the PCI runs at 35mghz and of course the AGP runs at 70 and have no problems doing anything . If I clock the PCI at 37 and the AGP of course at 74 I can do anything in 2d I want , Prime 95 for hours or any 2D software no problems. BUT at that speed I cannot run 3D games without at least a crash back to the desktop or worse. I have a K6III+ 550 that will run 630, ( 105*6 )on an ASUS P5A-B ( I know it's old please don't laugh ;-) It will run fine at 112*5.5 but only like I've said in 2D. The memory is PC133 Cas 2 so I don't think that's the problem. The harddrives are never corrupted at that speed , the motherboard L2 cache is disabled so I really think I've narrowed it down to the old Matrox G400 Max not liking the AGP speed. Tried AGP 1x but that didn't help, didn't think it would improve the system if I disabled sidebanding just to gain 7 mghz though I haven't tried it. What does anyone else think?
     
  2. ToRN

    ToRN TS Rookie Posts: 189

    You reached the edge of performance... :D

    ...at least, of your system :p. You're lucky to have get it this far already.
     
  3. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,919   +9

    Can you change the AGP bus speed ratio? If it's 2/3, you could try 2/4.
     
  4. Rick

    Rick TechSpot Staff Posts: 6,305   +52 Staff Member

    It's most likely due to your processor rather than your video card. Almost any video card can tolerate an AGP bus of 74mhz. Try adding more cooling to your CPU (Although, admittedly, you will not be able to get much fartehr if at all)
     
  5. uncleel

    uncleel TS Rookie Posts: 1,145

    Back in the old Socket 7 days, that was a terrific motherboard.
    I agree, Matrox G400 Max could be the weak link.

    If your not going to upgrade your platform, then try a used (cheap) GeForce or Voodoo card w/ their respective overclocking utilities.
     
  6. Niatross

    Niatross TS Rookie Topic Starter

    Reply to Rick:

    The only reason I dicounted the processor Rick is because it will run Prime 95 at the higher bus all day(2D!) It will run at 630 Mghz(105*6) remember but not 616 *(112*5.5) It will run a game for a few minutes at 616 but then it seems to just trip over itself either back to the desktop or the dreaded BSOD. All video cards are different and was just wondering if maybe I got a weak one. Who knows, maybe I'll try a cheap Geforce and see what it'll do it'd be a better 3d card than the Matrox anyway(but I don't think you could get a better 2D display than this Matrox puts out) Thanks for your input guys.
     
  7. ToRN

    ToRN TS Rookie Posts: 189

    Maybe your mem can't handle the FSB? typical error for overclocking memory.
     
  8. Niatross

    Niatross TS Rookie Topic Starter

    Don't think it is Torn

    I'm using PC 133 Torn, Actually running it under spec
     
  9. ToRN

    ToRN TS Rookie Posts: 189

    Re: Don't think it is Torn

    I knew that...

    The matrox could be the reason, but so could your CPU. You rely it works because it runs fine with higher multiplier, but an fsb overclocking is different. I could just be your CPU can't handle it.

    I could run my old K6-2 at 100*5.5 (550) but not at 105*5 (525).
     
  10. Niatross

    Niatross TS Rookie Topic Starter

    Your comment that I was replying to was about the memory ToRN. Your missing the point though, The cpu DOES run fine even under a full load at the higher FSB.( Prime 95 for hours ) 3D is what kicks it out.
     
  11. ToRN

    ToRN TS Rookie Posts: 189

    now you are missing my point. It is possible your CPU is running fine at 2D but not in 3D.

    3D is a lot more stressfull ALSO for your CPU. So even if your CPU is running normal in 2D, it doesn't mean it can handle all it's claculations at that speed. It choces when running complex 3D applications (like a game).

    I repeat: Your CPU isn't good enough for what you are doing. It could also be your matroxcard. Besides, with a K6-3 the advantages you get from overclcoking are not even worth talking about, so don't bother trying to push it further.
     
     
  12. Tawhid 1

    Tawhid 1 TS Rookie Posts: 59

    you have done a very good job my lad
    Now i am going to try it on my computer.
    Though my computer have a very good speed (I think).
     
  13. Federelli

    Federelli TS Rookie Posts: 382

    well... i can reach a agp speed of 80 mhz and a pci of 40 running my fsb at 156... stability for an hour or so, but full stability at 155.8 fsp and 79.9 agp and 39.9 pci
     
  14. Wild9

    Wild9 TS Rookie

    I know it's a bit late to reply but here goes anyway..

    It's amazing how well these K6-III+ chips have stood the test of time - I too, used to own one (450) until finances forced me to sell it on eBay.

    I also bought it to overclock, on a 112MHz bus:

    K6-III 450 @ 560MHz
    112MHz FSB (74MHz AGP/37.5MHz PCI)
    1x 128MB PC133 SDRAM
    Soltek MB with Via MV3 Chipset
    20GB IBM 7,200 RPM HDD
    230w PSU

    I could not alter the FSB/PCI ratio as this was a Super 7 board, but, the following AGP cards were tested at 74MHz AGP with absoluelty no problems whatsoever:

    . Voodoo 3 3000 (hot!)
    . Geforce 2 Ultra
    . Gefroce 4 MX 400

    I tried a Geforce 4 Ti 4200, and like you it worked in 2D bu no in 3D. I beleive it could be the card and/or your power supply that is the problem. You know your CPU can hit the high MHz, and the K6-III CPU's aren't picky about running at higher bus speeds - it's the other components like the video card and the AGP port or PSU that could be the problem. Also, having to disable the L2 cache on faster bus speeds means that the cache chips aren't fast enough - this may not be the best SS7 board to overclock with.

    Socket 7 never really was designed to run AGP, and most boards had a hard enough time running stock AGP cards. Only a few could actually remain stable in operation.

    I would definatly get a card that will make the most of type of CPU you have - even if at the end of the day you're stuck with standard AGP speeds. From testing games like GTA Vice City, NFS Underground, I found a huge improvement over the K6-2 but unfortunately, the instant the screen gets rammed you just don't have the FPU power or the bandwidth available to keep the frame rates high. In other words, it's not resolution that's a problem because of the card you're running, but the CPU power at hand. So you need a card that scales well with slower processors.

    I was previously an nVidia fan until they started screwing around with naming conventions and driver issues, so there may be a Radeon card that would be better for you, as they tend to give much better performance when FSAA and AF is switched on.

    Then again, for £60 in the UK I managed to get an Asrock board with a Duron 1800 that I ramped upto 2100MHz with an OC 128MB GF4 Ti 4200. I'm not being negative about that K6-III because for general use they are very good and I would imagine that yours goes like a bat outa hell, but compared to even a "budget" Duron, there's a world of difference for games. You could be buying a card to run modern games and be dissapointed. Games like Call of Duty are very feasible on that chip you have there, but the likes of Far Cry even with a fast card are not recommended.

    So in summary, I think it could be a Matrox, motherboard or PSU issue. You would get a good return on that CPU on eBay, promoting it's overclocking ability..

    Hope this helps.
     
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