feipoa wrote:

The Voodoo3 that was mentioned by swaaye on a 486 came as a surprise to me. I doubt there would be any performance boost in 2D graphics on a 486 though as compared to the Matrox G200.

On a 486 it's hard to notice the difference between the slowest GUI accelerators and the fastest. What's more noticeable is being able to at least run decent resolutions and color depths and so a G200 is definitely better than a 2MB Cirrus Logic card in that case. 😀

G200 is super fast anyway. You would probably need to run like 1600x1200x32-bit on an Athlon to feel it lag compared to something faster. That's not to say that G200 is special though as it's similar to a Banshee and TNT (they are all very fast).

feipoa wrote:

The reason for the avatar is to enourage anyone with this processor to come forward. I've been looking for one on and off for more than a decade. If I cannot get one to put into use myself, I'd at least like to see some test results with proven stability. If anyone else out there has one, please PM me -- if not for sale, I'll at least offer to test it FOC to the highest degree of professionalism.

I have the Cx5x86 120. It is an interesting chip but I've found that there's just not much point in choosing it over the AMD 5x86 due to compatibility and its lack of a speed advantage against the Am @ 160.... Also the special advanced features are unfinished and buggy and so might as well not be there.

One big issue with Cyrix chips like the 5x86 and 6x86 is that they have some incompatibilities with some programs and drivers. Patches needed to be released to make them work in some cases. So that's a red flag. Extra compatibility headaches suck. The POD has the same problem but on a hardware level (board compatibility is ugly with them). AMD 5x86 is just a revised 486 with a big writeback cache so it's pretty bulletproof.

I used the AMD x5-133 socket 3 in my M919 from about Jan 1997 until 2001, after which I switched to a Cyrix 5x86-120 and was blown away by the performance increase in everyday web browsing, office apps, etc. I do not play games, so I cannot vouche for its game worthiness though.

A few years thereafter, I enabled all of the Cyrix 5x86's nextgen enhancement features (except for branch prediction) and was pleasantly surprised, esp. w.r.t the FP_FAST feature, which made playing mp3s and web browsing a possibility on NT4 at the time (up to 33% increase in FPU performance was noted). Memory and cache throughput of a Cyrix 5x86-120 even outperformed that of the AMD x5-200, as posted earlier in another forum, although not in 3D performance.

I've been using this Cyrix 5x86-120 stably on NT4 for the past 9 years and have not run into any system instability, performance drops, or software which was incompatable. The instruction differences of the Cyrix 5x86 with that of an i486 may be with regard to the INVD and WBINVD instructions (cache), but I have not run into any incompatabilities on the two UMC 881E/886B-based motherboards I've extensively tested. Late era Cyrix-aware motherboards seem to be the trick though.

There are also a few chip revisions. The branch prediction is perhaps fixed in the newest, assuming the board will cooperate with the feature. Board awareness is definitely necessary for the chips to work near their peak.

As a nongamer and NT4 user you may want to check out the Vintage Computer Forums as we mostly think about Win9x, DOS and games around here. I'm definitely no NT4 expert. 😉 Although I did read that the Cx5x86 was NT4 certified.

I've got a 486 mobo that behaves oddly. I wonder if it's a chipset problem, and also related to the topic of "growth of impurities"? I notice that the board is "warped", as if it has been subject to some prolonged heat. The problem is that I can't install DOS on it - the DOS installation fails very quickly, complaining that it can't access the disk drive. I checked everything obvious, but couldn't locate the problem. I wonder which chip deals with IO - is it the northbridge?

I remember this problem occured with my working IO controller card, and also the integrated FDD controller. Curious. It was as if the mobo was getting confused about something which was straight forward and not confusing. I know, poorly explained sentence, but do you see what I mean?

However, I've noticed that the RAM, cache, and other chips on 486 mobos don't get hot. When switched on, I have put my fingers on these chips, and felt almost no warmth. OTOH, I've felt the most warmth from non-overclocked "slow" chips like 486 SX's that have no heatsink or fan.

AFAIK, none of these 486 SX chips that have been in this hot state over the years are malfunctioning today. Regarding failing onboard components - could this also be a capacitor problem, and not something to do with the "growth of impurities"? In my ignorance about this subject, I have not heard about this particular problem. It's interesting and a bit worrying!

The "growth of impurities" thing, also called "metal whiskers", is a phenomenon where you get growths of metal on exposed metals over time and it can cause circuit problems like shorts.
http://en.wikipedia.org/wiki/Whisker_%28metallurgy%29

There's also electromigration. Over time a semiconductor's circuit paths suffer a sort of erosion which causes the circuit to fail eventually. This can take decades though, depending on factors like heat and voltage.
http://en.wikipedia.org/wiki/Electromigration

I am not sure I would lean towards either of those being your problem. It's probably more likely that you are seeing failing solder joints, capacitors or other such problems. You could also just have poor quality hardware or a defective piece of hardware.

I'm worried that when I'm 64, my old hardware won't love me anymore. I just can't bear the thought of this. RG100 has a lie down, and wipes the sweat off his furrowed brow.

Edit:

swaaye wrote:

I am not sure I would lean towards either of those being your problem. It's probably more likely that you are seeing failing solder joints, capacitors or other such problems. You could also just have poor quality hardware or a defective piece of hardware.

That's good, because these things are much more fixable than the "creeping toxic death" described earlier! 😀

swaaye wrote:

The "growth of impurities" thing, also called "metal whiskers", is a phenomenon where you get growths of metal on exposed metals over time and it can cause circuit problems like shorts.
http://en.wikipedia.org/wiki/Whisker_%28metallurgy%29

This is new to me. Anyway, if I'd ever find that, I'd just think it's another blob of dust and clean it 😜
Cleaning computers is important 😉

And the electromigration can be a problem, but it can be slowed by good cooling. I wouldn't worry much about AMD 5x86's and electromigration. Right now these are quite common, but supply won't last forever though.

I think I'll move on to being nostalgic about early dual core CPUs by the time 486s have all died of electromigration. 😉

@swaaye
I appreciate the suggestion for vintage forum. I am there as well, but the pace is a lil' slow. It seems a good number of vogons users are actively using 486 hardware, which is where my interest lies. I may have oversimplified my case -- I do occasionally play Subspace on NT4.

@rg100

The IDE diskette controller either comes off the Southbridge or the Super I/O chipset. From Swaaye's wiki link on electromigration,

"Although electromigration damage ultimately results in failure of the affected IC, the first symptoms are intermittent glitches, and are quite challenging to diagnose. As some interconnects fail before others, the circuit exhibits seemingly random errors, which may be indistinguishable from other failure mechanisms."

Higher temps and voltage encourage this effect.

As Swaaye mentioned, caps are often the first to go. But I've seen boards where replacing the problematic caps only half-fixed the problem for about a month. There was something else causing the caps to go bad! I quit there and tossed the board as it wasn't worth the time. Sometimes, though, replacing a Northbridge is all it takes to fix things. Have fun with that. Putting in the wrong voltage RAM, for example, will also cause your Northbridge to act goofy -- some moments it works, others it fails.

FYI,
During the crystal growth process, differing materials are introduced to vary the composition for the purpose of controling the bandgap. This however, introduces a crystaline lattice mismatch, and adds strain to the material. To releive the strain, a dislocation is introduced (the crystal is no longer perfectly crystaline). The dislocations alter the electronic properties of the semiconductor and the unbound charges cause dislocations to act as wires to transfer charge.

When wavers are cut and polished, they are inspected for various impurities, e.g. via IR inspection. Ones which do not meet customer's requirements are either tossed out, or the areas of impurities are marked and not used. It is very difficult to find a whole wafer, that is 100% free of all growth imperfections. There will be usually be some kind of dislocation, be it edge or screw. When your chipset or cpu eventually dies, it often occurs due to such a dislocation. The presence of a dislocation or impurity may encourage electromigration.

There are other modes of failure though. The wiki links mentioned by swaaye are a good starting point for those interested. For example, the transistors in the chipsets are only rated for a certain maximum amount of current between the source and the drain, that is, in the absense of any impurity. Overvoltage will cause eventual burn out, esp. in the presence of dislocations.

The good news is that the AMD x5-133 is still cheap and easy to find, as well as the POD. The bad news is that appropriately priced eBay 486 motherboards have become nonexistant. I suspect that the quality of components in the motherboards are much worse than in the cpus, and as such, are more likely to hit the grave first. Be gentile with maxing out your settings if you want to take your 486 obsession well into your 80's.

feipoa wrote:

Be gentile with maxing out your settings if you want to take your 486 obsession well into your 80's.

I wonder who'll make it there first? Me or the hardware? Probably neither. 😉