meljor wrote:

Does anyone here have a dx5 running at 133mhz on this board? The manual states the same settings for the dx4 WB as the dx5 and n […]
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Does anyone here have a dx5 running at 133mhz on this board? The manual states the same settings for the dx4 WB as the dx5 and now it is running at 100mhz (or 3x40= 120mhz).
Only one jumper is different (jp12) but that doesn't make a difference.

So, how do i set a 4x multi for this cpu? I could set the dx2-66 settings but that is a WT cpu and has a lot of the jumpers different.

Help please 🤣

I actually asked that exact question a couple years ago, lemme look for the answer and I'll edit this reply in a minute or so 😄

edit:
Kudo's go to RacoonRider for finding this info for me 😀
https://dl.dropboxusercontent.com/u/99196890/ … DZ/P1020924.JPG

Notice the two red jumpers in the middle. These two control FSB speed.
_________JP25____JP26
25 MHz___2-3____2-3
33 MHz___1-2____1-2
40 MHz___1-2____2-3 <unlike the manual/th99/PCB prints
50 MHz___2-3____1-2 <not stated in manual

The blue jumpers control cache, they are set to 512Kb now.

The group of black jumpers near the blue ones select the CPU features: Multiplier, voltage(?), WB cache, SL enhancment. Notice the white jumper, JP12. When it's set 1-2, the system detects 5x86, otherwise DX4. This one is tricky.

The jumper settings are described on page 15-2 of the second part of the manual. However, if you just set it up, nothing will work or even POST! You have to set jumpers for DX4 SL-enhanced WB first, start the system, and only then turn it off and add JP12. I have now idea why it does not work otherwise, I triple-checked everything and still no post. You have to do this only once though.

Considering turbo button, it effectively halves FSB speed. L1 and L2 cache remain on, WB remains on, SL remains on.

I have not tried this myself though, but I don't see how this info would be false

Yup, works for me. If something happens and it instantly does not POST, don't panic, this board does this a lot when you do silly mistakes, like provide no power to IDE devices 😀

Btw, notice the fan connected to the power Molex. Just FYI, it does not work this way, the molex is an input and the output is the small connector to the left. I had my doubts before I attached the wires, it just so happens that they got into the picture when they shouldn't have.

Anyway, good luck with the board! I like it a lot.

The complete build looks like this:

RacoonRider wrote:

Yup, works for me. If something happens and it instantly does not POST, don't panic, this board does this a lot when you do silly mistakes, like provide no power to IDE devices 😀

Btw, notice the fan connected to the power Molex. Just FYI, it does not work this way, the molex is an input and the output is the small connector to the left. I had my doubts before I attached the wires, it just so happens that they got into the picture when they shouldn't have.

So it's basically an onboard fan adapter 🤣!

RacoonRider wrote:

Anyway, good luck with the board! I like it a lot. […]
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Anyway, good luck with the board! I like it a lot.

The complete build looks like this:

I still have my own AP43 rig (pics are in the retro rig photo thread, beginning somewhere), it's never been dismantled even though I couldn't get the mouse working again after I had moved (I didn't really troubleshoot this problem either though and went ahead to build a second 486 and this is when my ASUS SP3 kinda blew up...exciting stuff!! 😁)

So i set the settings first at amd dx4-s sv8b (that's how i got it running in the first place) and after booting i shut down and add the jp12 jumper? and then it will detect the 4x multi???

Correct?

Seems right 😀

This board drives me nuts!

Without jp12 (open) it runs at 3x33 or 3x40 perfectly fine. At 120mhz it is indeed a bit faster compared to my dx4 120 8kb WT cpu.

At 120mhz it scores about 45 in speedsys. At POST it says 486DX4 120mhz enhanced or something like that.

With jp12 set to 1-2 and fsb at 33mhz it hangs after detecting the harddrive. Without the harddrive and booting from a floppy i see at post unknown amd 120mhz?, speedsys reports amd 5x86 133mhz but gives me a score of 5! (and no hd working).

With jp12 set to 2-3 it runs like a dx4 120 again (40fsb is set) but it scores only a low 37 in speedsys 😕

Can i please have a photo of your jumper settings RacoonRider? I feel like i'm doing something wrong. Or should i just set it as a 3.45v amd 486 dx2? At this setting it might also run at 4x but without the enhanced or WB settings?

I'm so DONE with this board. After searching a long time for a 5x86 this is what i get: a non working Amd and a not overclockable cyrix gp100 .

I want my amd 5x86 at 160mhz!! 🤣

I tested at the 3.45v setting for the amd dx2 cpu. Normally a 2x setting should be translated to 4x right? Well, not on this board. It ran just as well as the dx4 wb settings (bit slower) but again at 3x multi....

I gave up, i will use the 100gp. It will not do 120mhz on this board and that's a shame but on stock settings it is just as fast as the amd 5x86 at 120.

Unfortunately this is my only pci 486 board and i wanted to clock as high as possible to play around with some 3dfx stuff. I will try these cpu's on a vlb board i have and see how they behave on that one.

Thanx guys for your help. After a good six hours i'm done with this little project 🤣 😵

Theres always tomorrow 🤣

meljor, the picture Tetrium linked shows my exact jumper settings.

Calm down a little bit, figuring out the correct config is a part of the game 😀

I know it is part of the fun, but i keep running in circles 🤣

I had the jumpers exactly like the manual states and like the foto from tetrium. I booted up dos and shut it off, placed jumper 12, booted again and my hd is no longer found and it was terribly slow in speedsys.

Tetrium also said:

________JP25____JP26
25 MHz___2-3____2-3
33 MHz___1-2____1-2
40 MHz___1-2____2-3 <unlike the manual/th99/PCB prints
50 MHz___2-3____1-2 <not stated in manual

The manual i downloaded has the 40fsb option right and it is the same as printed on the board. Maybe i have a different revision? Or maybe a bios version that doesn't support 5x86 with 4x multi?
I strongly believe a 2x setting for amd dx2 should result in a 4x translation by the cpu but it didn't, it gave 3x again. With jumper 12 on speedsys gave 133mhz amd 5x86 cpu but on POST it said unknown 120mhz cpu?
And since it was extremely slow something is off.

I'm out of options right now as i don't want to fiddle around with the jumpers when i do not know which one is for voltage. destroying the cpu with 5v would be even more bad 😢

So, any suggestion is welcome!

RacoonRider: what does your bios display at post? Does it recognise the amd 5x86 or does it also say unknown cpu? And what speed?

meljor wrote:

I know it is part of the fun, but i keep running in circles :lol: […]
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I know it is part of the fun, but i keep running in circles 🤣

I had the jumpers exactly like the manual states and like the foto from tetrium. I booted up dos and shut it off, placed jumper 12, booted again and my hd is no longer found and it was terribly slow in speedsys.

Tetrium also said:

________JP25____JP26
25 MHz___2-3____2-3
33 MHz___1-2____1-2
40 MHz___1-2____2-3 <unlike the manual/th99/PCB prints
50 MHz___2-3____1-2 <not stated in manual

The manual i downloaded has the 40fsb option right and it is the same as printed on the board. Maybe i have a different revision? Or maybe a bios version that doesn't support 5x86 with 4x multi?
I strongly believe a 2x setting for amd dx2 should result in a 4x translation by the cpu but it didn't, it gave 3x again. With jumper 12 on speedsys gave 133mhz amd 5x86 cpu but on POST it said unknown 120mhz cpu?
And since it was extremely slow something is off.

I'm out of options right now as i don't want to fiddle around with the jumpers when i do not know which one is for voltage. destroying the cpu with 5v would be even more bad 😢

So, any suggestion is welcome!

Does the board have anything damaged which might affect the multiplier jumper somehow?
Does this multiplier work with other chips?
(I haven't read back this entire thread so apologies if it's already been tried) You "might" try the same chip with 4x multi but at, say, 25MHz FSB, just to rule out it's related to something about the way your board handles stress (longshot, but at this point may be worth a try I guess).
Do you happen to have another 5x86 chip you could try? Any other board your tried 5x86 is compatible with so you can check if it'll run at 4x in there?
Different graphics card or other components? With cache disabled?

Btw, it wasn't me but something RacoonRider mentioned to me a couple years ago 😜

No, this is the only chip i have with a 4x multi. This board is running fine with a cyrix 5x86 gp100 and an amd dx4 100 and 120. The last is 3x40 ofcourse so stress can't be the problem.
I did try the 4x25 setting but it will boot at 3x. The only time it looked like it would boot at 4x the system became real slow so i guess this chip is simply not supported.

I still have to test de amd 5x86 on my vlb board just to see if it can run without problems. Will do that in an hour or so.

Manuals online are also contradicting: some i found only mention up to the cyrix 5x86 and don't even mention the amd 5x86. The strangest part for me is the dx2 setting booting at 3x instead of 4x.

I would like to know what racoonrider's bios says about the cpu and if it is recognised. Would also like to know his bios version.

I forgot to mention: i did get the amd 5x86 running at 3x 50fsb (it was fast) but i got funny colors from my s3 virge when starting windows.

Maybe it's a weird idea, but perhaps your jumper is broken? Might as well swap it with another one if it apparently makes no difference how you set that jumper 😜

Seems like your Virge can't handle 50MHz PCI bus... Do you have any Trios? They seem OK with it.

By the way, three out of three Am5x86 systems I encountered all ran 3x50MHz, including the VLB one (which turned out to be quite slow). Maybe that 4x multi is not worth it?

I'll check out what my BIOS says about the CPU, but as far as I remember, it's "Am5x86 133MHz" and "Am486DX4-150MHz Enhanced". I do need to check out.

Did you manage to check the bios version? And is it flashable on this board?

Otherwise i have to settle for 150mhz. i changed the virge to a trio64v+ but it behaves the same. Fortunately it is only when starting windows (boot logo ith funny colors), After it is fully loaded it looks all fine and it works very well.

Also had some good results with my favorite dos glide game screamer2. It runs VERY well with a voodoo2 and the 5x86 at 150mhz.
Still a tiny bit of lag at one level but otherwise pretty impressive performance, it is a pentium game afterall...Have to check screamer rally and see how that goes 🤣

I do feel like 160mhz would be even better as the speed difference between l1 and l2 is not that big at 150mhz due to lower timings.

BTW i did check the jp12 with the cyrix 100gp cpu and at the 1-2 position it switched perfectly fine to the 2x multi so i don't know why it doesn't work nicely with the amd 5x86. I really think it is not supported by bios, as speedsys did report 133mhz and later i found out that the l1 option in bios was greyed out (disabled?)

meljor wrote:

Did you manage to check the bios version? And is it flashable on this board?

Yup! Just did, I forgot I intended to 😀

The BIOS reports 5x86 correctly. My BIOS dates December, 5 1995.

Thank you!

According to wikipedia the 5x86 is introduced by Amd in november 95, my bios is from august 95. I don't know if the bios is upgradeable or not. At least now i'm sure what the problem is....