So where does it sit relative to the U5SX-33 - you want it to be lower than that?

Matth79 wrote:

So where does it sit relative to the U5SX-33 - you want it to be lower than that?

This build will completely replace the (currently unbuilt) U5SX in my signature.

My 486dx4 build system,you can compare it with your system

Texas Instruments 486.

yawetaG wrote:

Texas Instruments 486.

Any particular reason you are partial to it?

I’d go with the good old Intel SX 33, which is what I had back in the day and was a sensible option due to it being significantly cheaper than the DX. Exactly the same speed and unless you were doing CAD, etc, who needed a maths co pro?

It’s also a great example of those sleazy 90s marketing tactics that made the pc market feel like the old west back in the day. Early on Intel were taking working DX’s, disabling the maths co pro, and calling it an SX - all for marketing purposes.

I’m also a big fan of the DX2 66 Overdrive, but DOOM still lags. Anything faster than that is just a Pentium wannabe, so you might as well go Socket 7.

I don't see the point of polling people because you kind of seem to have your mind set on a specific build already.

However, if I were to pick something, I'd go with Intel DX4:

- performance is more important than the ability to run some CPU-sensitive games. DX4 should be fine for a really wide selection of DOS games. Frankly, at some point I realised that I obsess about speed-sensitive games way more than I actually play them;
- to me it's the last non-budget 486. I like my builds as high-end as possible. Of course, DX4 wasn't the absolute high-end CPU at the time of its release (Pentium 60/66 was) and its price dropped significantly as soon as AMD DX4 hit the market. But it wasn't a budget upgrade part like AMD 5x86 either;
- in my experience DX4 gives a lot less compatibility and stability issues than, say, 5x86. At least, on VLB motherboards. The performance difference is, again negligible — you still have your P133 for anything DX4 can't run;
- in turbo it should give you something between a 386@33 and a 486@33;
- ideally, I'd pick a WB-cache version of DX4, but the performance difference should be negligible.

@jheronimus if it read like I have my mind set on any part of this build then I must have miscommunicated myself; I am very much unsure on how to go about it. The only WB 486 I have is an Am486 with 8KB WB; is that faster than an i486 with 16K WT?

@badmojo I had a DX33 in the day but I did not know the SX/DX split did not amount to much speed difference back then - conventional wisdom at the time was that the SX was a no-no, especially for people who used a 386 before (even though that is a complwreyly different story.) I never had a DX2 and dont quite see why I would go for one instead of a DX4 either but it is a chip I never had so there is appeal in that as well. Maybe I have a board that can be wired to the Turbo button to disable the internal multiplier on a DX4 - that would be perfect really.

The UMC! GREEN CPU!! Though perhaps only because it's that weird "other" option people often forget about.

SW-SSG wrote:

The UMC! GREEN CPU!! Though perhaps only because it's that weird "other" option people often forget about.

I agree, GO GREEN Giant !

appiah4 wrote:

I never had a DX2 and dont quite see why I would go for one instead of a DX4 either

There is almost 2 full years between the two, 92-94. DX2 is associated by a lot of people with being a staple of DOS gaming golden years, sweet spot, while DX4 came out as a pleb budget alternative to Pentium 100 almost at the onset of Windows 95. Personally when I hear DX4 I think slow and pointless.
DX2 was the fast alternative to budged 386DX40s.
DX4 is a slow alternative to Pentiums.

When it comes to this time period I am fascinated by processors like Intel 486 SX2-50, was it available at all in retail channels? or only to laptop manufacturers? when did it come out? and how much was it? Seeing as SX-DX was just a marketing scam anyway, nobody other than engineers/scientists ran any FPU code, it could of been a great deal. Another notable Intel 486 CPU would be 1991! DX-50 with insane 50MHz FSB. AMD was quite aggressive at the time, selling 486DX40 (fastest they got) in 1993 at ~1/2 Intel DX2-50 price.

Did some research a while back:

~$700 for DX2-66 in 1992, for comparison SX-33 was $190. 1993 Pentium 66 twice the speed, DX2-66 half the price(~$360). 1994 Pe […]
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~$700 for DX2-66 in 1992, for comparison SX-33 was $190.
1993 Pentium 66 twice the speed, DX2-66 half the price(~$360).
1994 Pentium 100 again twice the speed, DX2-66 again almost half previous year price(~$200).
1995 Pentium Pro 200 twice the speed, TI DX2-66 1/3 previous year price ($66).

1991 486dx-50 is very insane,but only few motherboard can run it stably, 50mhz fsb requires very good quality motherboard, gigabyte ga-486im is one of them

I am trading away my WT cache Am486 DX4-100 for a Cyrix 486 DX40.

The DX40 would be a nice compromise between the SX/DX-33 and DX2/4 argument I guess? How good is the Cyrix DX40 chip and how likely am I to run into VLB troubles with it?

I have memories of going to computer swapmeets around 1997 (as a poor kid) and starting out with an SX33 and playing older dos games (Jetfighter, anyone?). It did struggle with doom, ran around 10fps IIRC

Later on I got a DX/33 and a VLB board with a cirrus logic VLB card, and doom runs great on it - a bit later on with a DX2/66, and it's slightly faster again

If i had the hardware, I would go back to a DX/33 and a fast ISA card, like a WD Paradise. It caps out at doom, but it still plays a lot of older games

appiah4 wrote:

how likely am I to run into VLB troubles with it?

Im putting together a 40Mhz fsb system currently and VLB video is not giving me any issues. Im only using it for video, though, and all other cards are ISA.

Munx wrote:

appiah4 wrote:

how likely am I to run into VLB troubles with it?

Im putting together a 40Mhz fsb system currently and VLB video is not giving me any issues. Im only using it for video, though, and all other cards are ISA.

The trade I went for fell through; if I had indeed been able to get the DX40 chip it would have been my choice for certain; but failing that, I believe my target for now will probably be the UMC U5SX-33, which is roughly equivalent to an Intel SX-40 anyway.

And now, for the motherboard; the contenders are:

Chicony CH-471-A

Data-Expert EXP-8046

ECS 486-UL-1

Octek Hippo-VL DCA

PC-Partner-486-CV.

No one had anything to say about any of the choices, really? *sadface*

None of the PCI rubbish! Go VLB!

Yeah, PCI would seem weird for a CPU like that. I'd vote for Octek, but I don't have practical reasons for that. Instead:

- the motherboard looks cooler than the others. What chipset does it use?
- I'd be intrigued to play around with Mr.BIOS.

However, it doesn't have ZIF and personally I hate sockets like that. So easy to bend your CPU pins 🙁

In all fairness, I think it's pretty hard to know all the characteristics/capabilities of a 486 motherboard without testing it. Compared to, say, Socket 7, they are not well documented, they are not consistent in their features (two motherboards using the same chipset can have huge differences) and there aren't a lot of widely popular models — apart from some Asus/AOpen boards that everybody seems to like. Hence, it's pretty hard to choose a board without some heavy research.