ClassicConnect

[parasquared]

as some of you know, i recently acquired a 486 pc and have been messing with it.

here are the specs:
- Intel 486 SX2 @ 50MHz
- 16MB of RAM
- MiTAC PWA-IH4077C motherboard
- Winic W-606 super I/O card
- 2.8GB Fujitsu IDE hard drive
- Trident TVGA8900D video card
- MediaVision Jazz16 sound card (soon to be replaced, as i'll touch on below)
- random Creative CD-RW drive (originally had a 2x Sony drive on their proprietary interface, however it quit working and the replacement sound card doesn't have CD interfaces anyways)
- 2400bps ISA modem (basically useless for anything other than Gopher and IRC, i'll get a faster one at some point)

as of present there's been a few issues:

- the system is extremely unstable.

sometimes it's random, sometimes it's consistent. memtest86+ always crashes at the same spot, timeless (one of my fav scene demos) always crashes ~20 seconds in, but i also will just get random lockups especially under windows. sometimes trying to use the modem will also lock up the system, however i've determined it's definitely not a resource conflict especially since it doesn't always happen.

i don't fully know why, it could either be the RAM or my CPU jumper configuration (or the CPU itself??? ), since this machine has a processor technically not listed in the motherboard's manual. however, i'm pretty certain that my current configuration of a 25mhz SX should be correct regardless. swapping ram sticks around doesn't appear to make it behave any differently either, and i've also already sprayed down the ram slots with Deoxit.

i'm also fairly certain it's not any kind of corrosion from the clock battery, it was slightly leaky when i removed it but nothing seemed to have gotten on the board itself.

- the motherboard detects the hard drive incorrectly. the CHS are correct, however it's picked up as being something like 480mb. this is easily bypassed with the Ontrack Disk Manager however.

- originally, i had MS-DOS 6.22 and Windows 3.1 installed on it, but i recently replaced it with Windows 95, thinking that would help with the instability. turns out, no, it made it even worse. probably related to the first thing though.

- the sound card sucks.

i have an AWE64 coming in the mail, so i won't have to deal with it soon, but its Sound Blaster Pro emulation suuuuuucks. most titles either flat out don't detect it or won't talk to it, especially for the sound effect side.

it's supposed to be compatible with a Pro Audio Spectrum 16 as well, however most titles refuse to talk to it as it doesn't use the original PAS16 drivers. SimCity 2000 under DOS was an interesting case, as it would actually detect the PAS16 correctly, however if it tried to use it (which happens immediately upon making a city) the music would begin to freak out and lock up the system not long after.

this card is also not the source of the instabilities, as the behavior doesn't change if i remove it.

- and of course, the CPU kinda sucks.

i do want to switch it out for something else, however i'm not sure how to go about it (do i get a 486dx2? an am486 or 586? pentium overdrive???)

if anyone has suggestions or tips, especially for the first issue, i'd love to hear 'em.
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- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[parasquared]

i've made some discoveries, including the fact that the SX2 itself is just garbage. apparently they didn't sell very well and they had to be underclocked to actually be stable, as well as this motherboard literally not supporting it properly.

anyways, i've ordered a new motherboard (mostly for 3.3v/PCI) and cpu (am486 dx4 @ 100mhz). hopefully that fixes all of my issues
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[ParzivalWolfram]

As someone helping diagnose the issue, you missed the best part: your 486SX2-50 for some reason only has working read cache, but NOT write cache.

[parasquared]

oh god yeah, i totally forgot about that lmao; yesterday was certainly a day and i forgot whatall happened
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- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[parasquared]

update:

i got the new motherboard at some point, however i didn't realize it uses 72-pin SIMMs instead of 30-pin. so now i have some ram on the way. the awe64 still hasn't shipped, i think i'm gonna need to bring that up with eBay. cpu is currently going through international shipping.
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[europa]

I'm eagerly awaiting updates. That sucks about the AWE64 though :/
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Your System ate a SPARC! Gah!

[nick99nack]

Message the seller about the AWE64 if you haven't, before contacting eBay. Sometimes you can work things out between the two of you without getting eBay involved.
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If you like browsing without an ad blocker, you might also like getting rid of your virus scanner, and running around with your pants down. --SomeGuy, 2016

[parasquared]

update: i messaged the eBay seller about 2 days ago, all they said was "that's weird lemme look into it" and never replied. i told eBay i never got the item and the seller just immediately refunded it. i'll have to ship some items out here soon so i think i'll just be stuck with the jazz16 card for the time being unfortunately.

wondering if it was some sort of really lazy scam or something, even though they paid for the label (or maybe that was fraudulent too? i have had that happen)
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[parasquared]

update: the RAM for the new motherboard arrived. the system is totally stable now, just slow (as to be expected for the SX; the new CPU hasn't arrived yet)

i've been running the scene demo that would always crash at ~20 seconds on the old machine, for nearly half an hour now.

interestingly, certain things seem to be running slower even compared to before. i wonder if the old motherboard was driving the CPU too hard and that's why it would get really unstable?

once i get the new cpu, i'll reinstall Windows 95 again (since i need to format the entire drive in order to use this new motherboard's LBA support) and i'll finally be able to use this machine properly, i hope
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[europa]

I too am in this episode

I'm glad the original processor isn't entirely the problem lol - I wonder how possible it would be to find a motherboard that actually properly supports it and make it into a DOS/Win3.1 rig.
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Your System ate a SPARC! Gah!

[parasquared]

a couple days late update:

the dx4 arrived, i installed Windows 95 and it's been working really great. but now i've discovered the issue of the video card itself being insanely slow and i'm not sure whether to blame the chip itself or the fact it's stuck on the ISA bus. in topbench, the vidmem test is nearly 400usec (!) and for some reason the total score is basically the exact same as before the processor upgrade, even though it definitely feels way faster.

considering i can now use PCI cards, i'm thinking of getting something like an S3 ViRGE, they're cheap and the subpar 3D performance won't really matter on this type of machine anyways.
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[europa]

So in short you had a shit processor and a shit video card, and the shit video card was ultimately the bottleneck but you couldn't tell cuz the processor was also shit?

In all seriousness, I think you'll see a lot of improvement by going with a PCI video card like a ViRGE. You have some scores to beat, with my TopBench results from my 486 and Pentium systems, as well!
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Your System ate a SPARC! Gah!

[claraberry]

[parasquared]

that's sorta what i figured, considering the card is from like... 1994 at latest, and is in a pc that was decidedly already pretty budget considering the other specs it had
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- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews

[parasquared]

been a while since i posted, so here's updates of what i can remember:

i got that S3 ViRGE in. it's better, but still performing a lot worse than i'd imagine it should. things like Whiplash/Fatal Racing still struggle at lowest detail, and topbench is still reporting a vidmem score that's a lot higher than it should be (at least i'd imagine). the card itself also has compatibility issues, notably that it stops working after a reboot if video bios shadowing is enabled? i have no idea why, and it sometimes still won't work properly with it disabled.

the Jazz16 is still pissing me off, but for another reason: samples above ~20khz typically plays too fast and can throw off the timing on things like video clips. somehow the only sampling rate i've found that DOES play back correctly is... 33075hz?? weird number but okay..

here's a couple samples of rain.mtm playing back in ModPlug Player:
rain.mtm playing back at 16000hz (correct speed)
rain.mtm playing back at 22050 (too fast)

i've ordered yet another AWE64 (model CT4520), hopefully this seller doesn't ghost me

the hard drive is dying. i suppose not really a surprise, but still annoying, especially since i'm not sure what to replace it with yet. i know the PicoIDE was recently announced, but it's still in the crowdfunding phase. not sure if i should just bum it out and hope the drive doesn't fully fail in the time it takes to get them into production, or if i should just roll the dice on a traditional CompactFlash adapter.

also, since i haven't really done a breakdown of the components since originally making this post, how about an update?

- AMD AM486DX4 @ 100MHz
- 64MB of RAM
- Chaintech 486SPM M104 motherboard with some kind of overclock mod that allows you to set the system bus higher than normal
- Winic W-606 super I/O card (the mobo has onboard serial, however i couldn't get it to work, so i still have to use this card unfortunately)
- 2.8GB Fujitsu IDE hard drive
- S3 ViRGE/DX graphics card
- MediaVision Jazz16 sound card
- random Creative CD-RW drive
- 2400bps ISA modem (i really should get something else but i'm lazy )
_________________
- parasquared

"In space there is no center, we're always off to the side"
- Ballad of Reverend War Character, Silver Jews