jamesbeat wrote:

As I said above, I have a PII, PIII, P4 and I have an original Pentium build underway, but it's a pain to keep a load of boxes ready to use at a moment's notice, so the more versatile my 'time machine' is, the better.

I also have a KVM switch though, so I suppose it wouldn't be too difficult to have them all set up if I really wanted to.

You got yourself an MS6905 Slotket -- so you'll be using your Ezra in a Slot 1 Board. That means just popping one card out for another if you want to swap in a Pentium II or Pentium III.... and plugging in the CPU fan. Almost as easy as swapping a Genesis cartridge! 😜

No, I bought a socket 370 board in the end.

The reason is that both of my slot 1 boards are OEM versions (Gateway, made by Intel) and I can't be confident that the C3 will work in them.

I may get a slotket eventually to try it out, because these are really nice motherboards, but that means taking a gamble, because if they aren't compatible with the C3, the money spent on the slotket will be wasted.

Since I managed to find a motherboard for about the same price as a slotket, I took the safer approach..

The motherboard I bought is a CUSI-FX, which is on the Via list of compatible motherboards.

The only drawback is that it has no ISA slots, which is why I might take a gamble on a slotket sometime in the future.

DOS PCI sound isn't necessarily going to result in a fruitless search, but there isn't much information on what sound chips work well with SIS chipsets or which SIS chipsets retain compatibility for ISA emulation under DOS.

Probably the two best chips when it comes to compatibility and sound accuracy are the ESS Solo-1 (ES1938/ES1946) and Yamaha YMF-PCI series. Both are available second hand quite inexpensively. The ALS4000 chip is also recommended in some corners, but it's much less tested.

Thanks for the pointers - they will give me a good start when researching sound cards.

My CPU arrived today.

I am happy to report that it works in my Asus CUSI-FX motherboard.

The morherboard is a bit more modern than I would like (no ISA ports as mentioned above) but the quality is good, and there are very extensive options in the BIOS, which is refreshing after all the OEM boards I have been messing with lately.

I've had rather a full evening, so I only got the chance to power it up briefly to see if it worked.

I also don't have a case cleaned up to receive it yet, so I'm reluctant to play around with it beyond a simple test.

I'm hoping to get it functional over the weekend so I can try out setmul.

Does the motherboard support a 50mhz FSB?

jamesbeat wrote:

I'm trying to build a machine that can be slowed down to replicate a 286, 386, 486 (and maybe a Pentium, though this is less important because I already have a Pentium Pro machine).
8088 would be awesome too, but I don't know if that's possible.

jamesbeat wrote:

The morherboard is a bit more modern than I would like (no ISA ports as mentioned above) but the quality is good, and there are very extensive options in the BIOS, which is refreshing after all the OEM boards I have been messing with lately.

This is the second person in a few days who is aiming for mainly DOS era gaming but building a system without an ISA slot. Srsly.

gdjacobs wrote:

Does the motherboard support a 50mhz FSB?

I don't actually know enough about that to give you a good answer, but here's a link to the manual:

https://www.google.com/url?sa=t&source=web&rc … oPeLIZpCHuleBXE

squiggly wrote:

jamesbeat wrote:

I'm trying to build a machine that can be slowed down to replicate a 286, 386, 486 (and maybe a Pentium, though this is less important because I already have a Pentium Pro machine).
8088 would be awesome too, but I don't know if that's possible.

jamesbeat wrote:

The morherboard is a bit more modern than I would like (no ISA ports as mentioned above) but the quality is good, and there are very extensive options in the BIOS, which is refreshing after all the OEM boards I have been messing with lately.

This is the second person in a few days who is aiming for mainly DOS era gaming but building a system without an ISA slot. Srsly.

That was purely a budgetary thing - I basically searched for the cheapest motherboard I could find that was also on the Via list of supported motherboards.

I couldn't stretch to a board with an ISA slot (which understandably cost a lot more) plus an ISA sound card, and still have enough money left over for the CPU.

I figured that the smart thing to do would be to secure a CPU and worry about the rest later.

As long as I have the CPU, I can upgrade the motherboard to something with an ISA slot when finances allow.

I know it's suboptimal, but a board without an ISA slot still beats a CPU sitting in a box on a shelf.

jamesbeat wrote:

gdjacobs wrote:

Does the motherboard support a 50mhz FSB?

I don't actually know enough about that to give you a good answer, but here's a link to the manual:

https://www.google.com/url?sa=t&source=web&rc … oPeLIZpCHuleBXE

I read it already. I'm curious what the BIOS allows in the FSB selection box.

gdjacobs wrote:

jamesbeat wrote:

gdjacobs wrote:

Does the motherboard support a 50mhz FSB?

I don't actually know enough about that to give you a good answer, but here's a link to the manual:

https://www.google.com/url?sa=t&source=web&rc … oPeLIZpCHuleBXE

I read it already. I'm curious what the BIOS allows in the FSB selection box.

I don't see a FSB option anywhere in the BIOS.

Could it maybe be called something else?

EDIT:
I had the board in 'jumperfree mode', which removes certain options from the BIOS menus.

With jumperfree mode disabled, I was able to see the FSB options.

The slowest it goes is 66MHz

Whipped cream but no cherry.

Can you elaborate?

I'm still on the learning curve with this stuff....

50 mhz FSB clock obviously allows you to throttle a little bit deeper. Still, 66 mhz will allow your C3 to operate like a slow 386DX.

I thought that was what you meant, but then I thought maybe it was something else because the difference is only 16MHz.

I really need to get this machine assembled so I can concentrate on learning about this stuff.

I'm making some modifications to the case at the moment, so I haven't sat down and done my research yet.

gdjacobs wrote:

Other results indicate the real performance of a 286 is about 10-20% slower than a 386DX of equivalent clock.
download/file.php?id=26613&mode=view

With full SETMUL slowdown options in play at 66mhz FSB, my C3 can achieve performance approximating a 386DX-25 as per NSSI. I anticipate 50mhz FSB and degraded memory timings will deliver fast 286 performance, but I'd love to hear your results.

None of the settings in my BIOS took the Ezra any slower than the benchmarks I posted earlier (386DX-25/33)... but I just tested my Nehemiah and at 66x4 with caches disabled I get...

3.87 in SpeedSys, 4.6 3DBench and 1.1 in PCPBench ! Sadly the with the Nehemiah the system will freeze up if I try and set the FSB to 50mhz... though perhaps if I do that with DIP switches rather than in software it will boot up. This has to be 286 territory, no?

Edit: The lowest the system on a 50mhz FSB is 500mhz (50x10) with caches disabled. That gives me slightly lower scores than 66x4 with...

3.36 SpeedSys, 4.2 3DBench. PCPBench won't go lower than 1.1FPS. Also Landmark says it is running like a 21Mhz AT and the System Information CPU Benchmark is 8.5.

infiniteclouds wrote:

None of the settings in my BIOS took the Ezra any slower than the benchmarks I posted earlier (386DX-25/33)... but I just tested […]
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None of the settings in my BIOS took the Ezra any slower than the benchmarks I posted earlier (386DX-25/33)... but I just tested my Nehemiah and at 66x4 with caches disabled I get...

3.87 in SpeedSys, 4.6 3DBench and 1.1 in PCPBench ! Sadly the with the Nehemiah the system will freeze up if I try and set the FSB to 50mhz... though perhaps if I do that with DIP switches rather than in software it will boot up. This has to be 286 territory, no?

Edit: The lowest the system on a 50mhz FSB is 500mhz (50x10) with caches disabled. That gives me slightly lower scores than 66x4 with...

3.36 SpeedSys, 4.2 3DBench. PCPBench won't go lower than 1.1FPS. Also Landmark says it is running like a 21Mhz AT and the System Information CPU Benchmark is 8.5.

Hey, infiniteclouds, I've just been reading this topic since I'm working on my C3 flexible build trying to cover 386-pentium time span (going even higher with a swap of P3 1.4s Tualatin). However I wonder why are you trying to get slower than 386? Is there some sort of killer app for you in that territory? Or that's just sport type of thing?

This was the first game I ran into that was too fast for my K6 at "386 Speeds' Might & Magic III: Isles of Terra running too fast. Functionally the game played fine but the animations were too fast. At the usual bottomed out (lowest downclock, all cache disabled) speeds for these CPUs the graphics BUS still seems to be a factor for some games. Running a fast PCI or AGP card isn't necessarily going to give you the same performance as a true 386 that would be running graphics through a slow ISA bus. I thought about putting an ISA VGA card in the system but unlike PCI/AGP in BIOS there is no easy way to swap between the two, or even three, choices. It seems that if you can get your CPU into 286 speeds, however, that the expansion BUS becomes so crippled that it becomes irrelevant.

Ah, I see. Thanks!