VOGONS


Reply 20 of 28, by feipoa

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That's great. Not many people around these parts are running a system with an AMD DX4-100-WT CPU.

Plan your life wisely, you'll be dead before you know it.

Reply 21 of 28, by Skyscraper

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Not many people indeed !

On page 13 in the service manual you can see that the v1.0 motherboard lacks 3v support .

You can probably just ignore that fact! I use the exact same Venturis Socket-3 motherboard v1.0 with a Pentium Overdrive @100 Mhz and the board seems to have no issues with delivering enough power so it should handle the DX4, even at 5V. If you happen to find an Intel DX4 Overdrive with a built in VRM for cheap it could be worth to upgrade as the AMD DX4 can fail from running at 5V even if it probably will take many years. Be sure to use a heatsink and fan when running the AMD DX4 as it probably gets pretty toasty.

If you want to use 68MB memorey again try to downgrade the BIOS to the one you were using, the AMD WT DX4 probably works with any BIOS version. Im using Phoenix BIOS 4.04, I could take a BIOS dump later if you want a newer 68MB capable BIOS.

The service manual from 1996 do say this though.

"The VENTURIS 486 computer is currently equipped with a new main logic board that contains a Phoenix 4.04 BIOS."

That could indicate that you need a new BIOS chip to be able to use the 4.04 BIOS as they mention it comes with the "new main logic board", probably the v2.0 one.

As I have a v1.0 motherboard with the 4.04 BIOS it is possible to use this combination, I just do not know if its a straight forward flash. My system already had the 4.04 BIOS when I got it.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 22 of 28, by Tetrium

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bbhaag wrote:

Success! Sorry it took so long for my follow up but with the holidays and the need to return the wrong cpu it just took awhile.

Anyway, it looks like you guys were correct. I installed a DX4-100NV8T cpu tonight and it booted immediately. My system recognized the cpu without any need to change jumpers or BIOS settings and has been rock solid for the past hour.
Thank you guys so much for helping me solve this. Much appreciated.

Glad you have it running again 😀

I don't know about running 3.?v chips at 5v though. Some may be able to handle it and some may have great difficulties but I don't know the specifics except that perhaps 3v chips made with a larger manufacturing process may be able to cope better, but it's best to check this chip for chip I guess.

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Reply 23 of 28, by Skyscraper

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Tetrium wrote:
bbhaag wrote:

Success! Sorry it took so long for my follow up but with the holidays and the need to return the wrong cpu it just took awhile.

Anyway, it looks like you guys were correct. I installed a DX4-100NV8T cpu tonight and it booted immediately. My system recognized the cpu without any need to change jumpers or BIOS settings and has been rock solid for the past hour.
Thank you guys so much for helping me solve this. Much appreciated.

Glad you have it running again 😀

I don't know about running 3.?v chips at 5v though. Some may be able to handle it and some may have great difficulties but I don't know the specifics except that perhaps 3v chips made with a larger manufacturing process may be able to cope better, but it's best to check this chip for chip I guess.

I think the AMD 486 3.45V chips are rated for 3v - 4v with some later 3.45v chips rated for 3v - 5v.

I do not think I have heard of someone killing an AMD 486 chip by using 5v but it could probably happen, especially if running without a fan. Back in the day people often diddnt realize or care and upgraded their 5v systems with cheap 3.45v AMD DX2 and DX4 CPUs as Intel DX4 Overdrive CPUs were expensive.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.

Reply 24 of 28, by Tetrium

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Skyscraper wrote:
Tetrium wrote:
bbhaag wrote:

Success! Sorry it took so long for my follow up but with the holidays and the need to return the wrong cpu it just took awhile.

Anyway, it looks like you guys were correct. I installed a DX4-100NV8T cpu tonight and it booted immediately. My system recognized the cpu without any need to change jumpers or BIOS settings and has been rock solid for the past hour.
Thank you guys so much for helping me solve this. Much appreciated.

Glad you have it running again 😀

I don't know about running 3.?v chips at 5v though. Some may be able to handle it and some may have great difficulties but I don't know the specifics except that perhaps 3v chips made with a larger manufacturing process may be able to cope better, but it's best to check this chip for chip I guess.

I think the AMD 486 3.45V chips are rated for 3v - 4v with some later 3.45v chips rated for 3v - 5v.

I do not think I have heard of someone killing an AMD 486 chip by using 5v but it could probably happen, especially if running without a fan. Back in the day people often diddnt realize or care and upgraded their 5V systems with cheap 3.45V AMD DX2 and DX4 CPUs as Intel DX4 Overdrive CPUs were expensive.

This could very well be the case. And the chips of that era seem to be much better at coping with a 50% overvolt (maybe not for extended periods of time though, but just a quick POST with it at 5v might not be as deadly) than the much later chips so chances of an accidental 50% overvolt killing the chip outright might be slimmer...but in exchange for that the chip 'can' be put into the s3 socket in 4 ways instead of only the 1 correct way 🤣

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Reply 25 of 28, by bbhaag

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feipoa wrote:

That's great. Not many people around these parts are running a system with an AMD DX4-100-WT CPU.

Why is that? I noticed you and Skyscraper mentioned the same thing. Any particular reason?

Reply 27 of 28, by Tetrium

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bbhaag wrote:

I'm not sure why you guys think the socket I'm using is a 5v one. The Dx2-66 that came with the machine is a 3v chip so it is doubtful DEC would put a 3v chip in a 5v socket.

I've seen stranger things 😜
But if you're the original owner of that machine, then what you say does have logic behind it. But in the end it's better to know for yourself because sometimes even those companies themselves could just be lying 😜

Btw, most DX2-66 chips I've seen were 5v ones, but there are some 3.3v DX2-66's around.

Whats missing in your collections?
My retro rigs (old topic)
Interesting Vogons threads (links to Vogonswiki)
Report spammers here!

Reply 28 of 28, by Skyscraper

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Tetrium wrote:
I've seen stranger things :P But if you're the original owner of that machine, then what you say does have logic behind it. But […]
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bbhaag wrote:

I'm not sure why you guys think the socket I'm using is a 5v one. The Dx2-66 that came with the machine is a 3v chip so it is doubtful DEC would put a 3v chip in a 5v socket.

I've seen stranger things 😜
But if you're the original owner of that machine, then what you say does have logic behind it. But in the end it's better to know for yourself because sometimes even those companies themselves could just be lying 😜

Btw, most DX2-66 chips I've seen were 5v ones, but there are some 3.3v DX2-66's around.

Well I can only speak for my motherboard which seems to be 5V only, on the other hand my board uses the Trio64 video chip and not the Trio32 chip mentioned in the service manual so I guess there can be some differences between the boards within a board revision. Use a fan to make sure the CPU isnt running too hot and everything will be fine, if the system has been running a 3V CPU up until now it can continue to do so.

New PC: i9 12900K @5GHz all cores @1.2v. MSI PRO Z690-A. 32GB DDR4 3600 CL14. 3070Ti.
Old PC: Dual Xeon X5690@4.6GHz, EVGA SR-2, 48GB DDR3R@2000MHz, Intel X25-M. GTX 980ti.
Older PC: K6-3+ 400@600MHz, PC-Chips M577, 256MB SDRAM, AWE64, Voodoo Banshee.