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Nehemiah build problems

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First post, by BufordTJustice

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Hi all,

I'm currently building a couple of machines with Via C3 CPUs to have a play with speed adjustment for old gaming, something I've not done before. I'm not ashamed to admit that I've tried to copy some builds posted on the forum already. I'm going for a Nehemiah CPU on one machine and an Ezra-T on the other.

I'm very stuck on the first build using the following components and would appreciate some help from someone who has already gone down this route...

VIA C3 Nehemiah 1.2GHz CPU - bought here; https://www.ebay.co.uk/itm/CPU-Processor-VIA- … 353.m2749.l2649

MS-6905 Master Rev 2.0 slotket

Gigabyte GA-6BXC Rev 2.0 motherboard

A stick of PC133 CL2 SDRAM

The rest is bare bones at the moment - a floppy drive, Voodoo3 2000 AGP card (with the jumpers configured on the GA-6BXC for that type of card) and that's all.

The turbo jumper is also set to default.

The machine was tested with a PII-400 chip and it all posted correctly. The bios was flashed with the one from Powerleap and then the CPU was swapped out for the VIA and slotket.

I've read in other posts that a 133MHz FSB maybe pushing your luck with this board and I have to assume the caps aren't as great as they once were so I thought of getting the thing setup at 100MHz FSB to start with.

I've got the slotket configured to handle 1.45v and 100FSB for the CPU using the jumpers, the motherboard SW1 bank is also set to 100FSB and the SW2 bank is set for a 9.0 multplier (using the manual) but I'm getting some odd readouts at post - I'm seeing 900MHz (180x5.0) which bears no relation to what I'm setting. What am I missing here? The slotket has been tested running a S370 PIII in another 440BX board. I think I need an idiots guide to the motherboard and slotket jumpers for my particular CPU and what people here configure them to run at by default as I assume that affects how SoftFSB and other utils will function.

Any pointers on this one would be appreciated and thanks for reading through my post. I'll obviously answer any follow-up questions with more detail if needed (didn't want to write War & Peace to start with and bore you all to tears).

Many thanks...

Reply 1 of 4, by BufordTJustice

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I've done some more reading online and it would seem the strange frequency / ratio reported at post is to be expected. I've heard the Nehemiah can get away with passive cooling but it's running very hot so I'm worried I'm over-volting it. I should move on to testing out some slowdown and system reporting tools but still don't know if the system is configured correctly...

Reply 2 of 4, by BufordTJustice

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OK made some progress; heatsink didn't have a flat base (there's a centre ridge not touching the chip). I've swapped this out with a better heatsink and the temps are cooler. I'm making an assumption that the ratio switches on the motherboard don't have any affect. Set the slotket to FSB133 and played around with the SW1 bank and now have it posting at 1.19GHz.

Reply 3 of 4, by red-ray

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BufordTJustice wrote on 2020-12-23, 03:39:

I'm seeing 900MHz (180x5.0) which bears no relation to what I'm setting. What am I missing here?

I suspect this is down to the BIOS only looking at the low four bits of the multiplier as x5.0 is 0x00 and x9.0 is 0x10. What do utilities report from Windows NT/2000/XP/2003?

I would be interested to know how fast your C3 will run, I can almost double my C3-M speed from 800 MHz (x6.0 ) to 1.53GHz (x11.5) !

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Reply 4 of 4, by BufordTJustice

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Hi Red,

Thanks for the info - you're right that's probably it. Speedsys gives me the correct CPU with a score of just over 800 which looking in the forums seems in the ballpark.

Next problem I have is I cannot install Win98 on the box - it consistently freezes at the Windows splash screen after the setup detects devices and restarts. I've tried multiple AGP cards, memory sticks and have no other cards fitted onto the board. I've swapped back to the PII CPU (reset the switches on the board) and everything is fine. I've tested the C3 CPU on a native 370 board (MSI 6368) and it functions with no problems in Win98. I'm concerned the caps may be going on the Gigabyte board.

I'm going to try a PCI video card and swap the IDE to SATA adapter over on my hard drive. I might try Win2K / XP to rule out something with 9x.

I'm still not sure where I stand as far as the FSB133 is concerned - is the board actually overclocking the AGP bus as the motherboard switches aren't set to that but the slotket is (?). Does anyone have any pointers as to what bios settings to pay attention to? Would slightly overvolting the CPU using the slotket jumpers help at all?

Many thanks...

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