133MHz FSB with PC100 memory?

I'm trying to setup my 1.2 GHz Athlon. My PC133 memory comes on Monday, but I want to set it up in the meantime with my older PC100 memory for now.

My question is, should I set my FSB speed to 100 in order for it to run with my PC100 memory for now? Or is it possible to set the FSB to 133 and somehow have the memory clock set to 100? In other words, is the memory clock dependent on the FSB clock, or independent of it?

Also, if I have to stick to 100 for the FSB, is it okay to push the multiplier up to 12 to get to 1.2 GHz for now?

I'm using an Abit KT7A mobo, so I need to use the SoftMenu III in the BIOS to set the CPU and memory parameters. Any help would be greatly appreciated.

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  1. I'm not exactly certain on the workings of that mobo, but look for a FSB:RAM frequency ration. I think this is called running it asynchronously. (might have a mispelling there)

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  2. No, the RAM and CPU run at the same bus. What you should do is just set the FSB to about 110 or so. If you have good memory, you might get it higher than that, but it doesn't always happen. Then up the multiplier some, if you want. It's just not usually a good idea to risk frying something when your other stuff is coming a few days later.

    Apple? Macintosh? What are these strange words you speak?
  3. Thanks. But say I keep the FSB down to 100. Is it okay to then set the multiplier to 12x, given that the Athlon is a 1.2? Or could that fry something else? I ask because I'm not completely sure what else the multiplier setting affects besides the CPU frequency...
  4. Just keep it as a slower clocked Athlon. It won't perform very much differently. You could raise the multiplier, but what's the point? Greater heat for not very much more performance.

    Apple? Macintosh? What are these strange words you speak?
  5. 12 x 100 should be just fine, you will probly find it will go higher.

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  6. NOPE....ABIT can run a diff dram clock speed

    I'm not in touch with my feeings, and I like it that way!
  7. You can run your ram at 100mhz or 133mhz simply by changing the dram clock to either "HOST" or "HOST +PCI"

    If your CPU is the B-type You can stay at 100FSBx(12) and set your DRAM clock at "HOST"

    OR, If your CPU is C-type, you can run you CPU 133x(9)=1200
    and set your DRAM to "HOST-PCI" = 100mhz dram clock.

    Or you can run at 100fsb(12) and use "HOST" for the dram clock, then add 1mhz at a time to the FSB until the ram can't take any more =8-)

    I'm not in touch with my feeings, and I like it that way!
  8. Well, on the KT7A, if you run your CPU at 1200 (133x9), the DRAM Clock has no option except HOST. I tried PageUp and PageDown, but it wouldn't let me change to anything else but HOST. There is no option for HOST-PCI or HOST+PCI. If I run it at 1200 (100x12), on the other hand, then it gives me the option of running the DRAM Clock at HOST or HOST+PCI.

    But anyway, here's the curious thing. For about a day before I got my PC133 memory, I was still running on my old PC100 memory. But I decided to push the CPU up to 1200 (133x9) anyway, and as I said the only option for the DRAM Clock setting was HOST. So I left it like that, and it ran.

    What I can't figure out now is why it managed to run with an FSB of 133, when my memory was a 3-year-old PC100 128MB module. I mean, now that I finally got my PC133 modules in today, I popped them in and they're fine, but I'm not sure how to tell whether the DRAM clock is running at 100 or 133. I left the DRAM Clock setting as it was (HOST), but I just can't understand how that could be 133, if my PC100 memory was able to take it.

    Any insights would be greatly appreciated.


    P.S. And yes, my Athlon 1.2 is a "C" type (266MHz FSB).
  9. what memory timing settings are you using, 7ns (2/2/2) or 8ns (3/3/3)? The slower 3/3/3 will give the PC100 a fair chance of runing at 133. Hopefully your PC133 memory is CL2 set in your bios at 2/2/2.

    WCPUID will give you basic stuff about your cpu and memory speeds.

    SiSoft Sandre 2001SE will give you detailed information about your system and devices, including memory specification and capabilities.

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  10. Ah your'ee right about the dram clock...i was thinking about my older abit with kx133 chipset..that one has the ability to run "host-pci", but my newer ones don't =8-0,
    I just assumed they would but when I looked they would only go 133/host.

    But you could run 100fsb/33pci, then...up the individual
    fsb selector below that until the ram can't take any more.

    I've had a few pc-100 sticks that actually ran way over that...some up to 133 at cas2 even. It depends on timings and interleave settings, dram latch...etc

    I'm not in touch with my feeings, and I like it that way!
  11. Ok, his memory was here two days ago, so I don't think any of this really matters anymore.

    Apple? Macintosh? What are these strange words you speak?
  12. Gee thanks, dad

    I'm not in touch with my feeings, and I like it that way!
  13. Fatburger: actually, it does... I was still trying to figure out whether my DRAM clock was actually running at 133, since it didn't make sense that my old PC100 mem was able to handle it at that setting... But I'll go home and check the memory settings, like peteb suggested...
  14. Okay, so I checked the exact type of my Micron PC133 memory, and I it's 7.5ns, CL2 capable, but only CAS3, I think.

    But when looking at the "Advanced Chipset Features" screen of my BIOS, all three DRAM bank timing settings are currently set to "SDRAM 8/10ns". The only other options are "Normal", "Medium", "Fast", and "Turbo". Which one do I use to get it to be the 7ns (2/2/2) setting?

    Also, is it possible to get CAS3 memory to run successfully at CAS2? Or can that damage it over time?

  15. hmm - not sure on that board. if you leave it at stock voltage, you are not going to harm it, so try at the fastest setting and see if it boots, work backwards.

    You can then re-validate in SiSoft to check your results!

    Wheather Cas3 RAM will run at 2 is largely a matter of component quality and luck. You can nudge the odds by increasing the voltage to the RAM, but this can lead to earlier component failure etc. No figures for how long one way or the other though.

    -* This Space For Rent *-
    email for application details
  16. Thanks, peteb. Sandra's awesome, btw (except for a few mislabelings, etc.). So is Micron. I was able to get about a <b>50-60% memory performance increase</b> by playing with the BIOS parameters. I made the following changes:

    <b>SDRAM Cycle Length:</b> <font color=blue>3 -> 2</font color=blue>
    <b>Bank 0/1 DRAM Timing:</b> <font color=blue>SDRAM 8/10ns -> Turbo</font color=blue>
    <b>Bank 2/3 DRAM Timing:</b> <font color=blue>SDRAM 8/10ns -> Turbo</font color=blue>
    <b>Bank 4/5 DRAM Timing:</b> <font color=blue>SDRAM 8/10ns -> Turbo</font color=blue>

    The above changes put me in CL 2-2-2 mode, according to Sandra. I then also changed the following:

    <b>DRAM Bank Interleave:</b> <font color=blue>Disabled -> 4-way</font color=blue>
    <b>Delay DRAM Read Latch:</b> <font color=blue>AUTO -> No Delay</font color=blue>
    <b>Fast R-W Turn Around:</b> <font color=blue>Disabled -> Enabled</font color=blue>

    Before all the changes, Sandra's Memory Benchmark rated me <b>well below</b> a "VIA KT133A PC133 CL2 SDRAM" system. After the changes, I was actually <b>well above</b> it. Like I said, overall the ALU and FPU bandwidths increased by about 50-60%.

    The thing is that now, even though I'm booting up fine and Windows seems to run fine, I'm getting a pop-up error while playing <i>Baldur's Gate II: Throne of Bhaal</i> (something like, <b>"Error in module <unknown>. If the problem persists, try restarting Windows."</b>). It always seems to occur in the same area of the game. The error doesn't crash Windows or anything, but it does crash the game. So now I'm wondering if this could have anything to do with the changes I made to the memory parameters, especially the last three.

    I guess what I'm asking is, if you were to set those memory parameters too aggressively, what kind of problems would you see? Would your system just hang after some time or refuse to boot? Or could you actually see more subtle errors, like the kind I'm seeing in the game?

    Thanks again,
  17. Whoops, sorry. Missed a couple of posts in there. Didn't realize you guys had stopped talking about his specific situation.

    Apple? Macintosh? What are these strange words you speak?
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