If it was me, I'd experiment with the jumpers blindly. If it said DX2 when you booted up, I think you might be safe to let it boot up long enough to get more info about what speed it's running at. If anything, it's underclocked, so it should be safe. Then try one jumper at a time to see if you can get multipliers to change, etc. But that's just me. Maybe that's reckless, but my curiosity would probably win out. 🤣.

clueless1 wrote:

If it was me, I'd experiment with the jumpers blindly. If it said DX2 when you booted up, I think you might be safe to let it boot up long enough to get more info about what speed it's running at. If anything, it's underclocked, so it should be safe. Then try one jumper at a time to see if you can get multipliers to change, etc. But that's just me. Maybe that's reckless, but my curiosity would probably win out. 🤣.

I've got the feeling that this mainboard his 5v only. Olivetti was more of a typewriter company, so performance wasn't among their top priorities.
And the "Socket 3" doesn't have to mean anything, you know. It's just a mechanical piece.
Maybe these were choosen because they were cheaper at the time than their socket 2 counterparts.
Besides, the BIOS doesn't recognize the DX4, only the DX2 (not that it would matter, the CPU works nevertheless).
So maybe the whole system was designed before DX4 chips were available.

I dunno, I'm a bit scared to turning it on... even though it says DX2, what would happen to the CPU ? It could overheat and perhaps break... now if it was a more modern processor, let's say for example an Athlon or a modern Pentium, whatever, they are cheap and if one breaks I'd just get another... but it's a 486DX4 we're talking !!! It's like a piece of history and the processor is fully working, I'd feel very ashamed if I'd break it.
The fact that it turns on, it says DX2 and the PC boots doesn't mean it can sustain 5v the whole time I need to benchmark it, it might break after an hour or so... and I still don't understand where those voltage jumpers are...

I dunno what to do actually... I have no idea if it'd survive "as a DX2" or it'd die from the voltage after some time of being turned on...

Jo22 wrote:

Or just write a mail to the support of Olivetti.
They even have a contact form on their website.

http://www.computerhope.com/comp/olivetti.htm

That's interesting... the e-mail link redirects me to olivetti.com which looks dead...

Gonna take a wild guess and say that board doesn't support 3.3V processors. Also, probably only up to 2x multiplier.

Your best bet is a DX2-66 or similar (5V version!). I wouldn't risk a 3.3V part in this.

Would a 3.3v CPU even boot in a 5v socket before dying ?

Yes.

Great...

I think I'll plug in back the SX2 UNTIL someone can't find a manual for that motherboard, I can't find any online and even worse at home.

So at least, with the manual, we can be 100% sure if there are voltage regulator jumpers and how to set them in 3.3v mode, or if I need one of those bulky converters.

In any case, I'll upgrade it to the DX4-T100, even if I need to buy that bulky converter, but first let's wait for a manual and check if there are the jumpers already... back on the little bit slower SX2 now 😢

Your best option is probably an intel DX4 overdrive.

If I can afford/find one to buy :\

A Pentium Overdrive would be even better at that point, or not ?

The pentium overdrive is tricky.
On some motherboards, it's slower than a DX4 (for example on my MB1433/50UIV-A, which is already more advanced than your board)
On some motherboards its simply won't work (for example in my packard bell 486 with a PB420 motherboard).
If well supported, it's only a bit faster in most of what you want to do with a 486, and really faster in pure FPU scenarios only. (an example of that scenario would be a late PCI motherboard such as my MB8433)
But in those scenario, pretty much everything from a real pentium (from 133MHz) to any modern PC will be more interesting anyways.

(For reference, an Intel 486 will give 4/7/10 FPS in quake at 33/66/100 MHz on a good motherboard, and the POD will reach 16-18, on the MB8433)

If you don't want to risk your DX4 chip and cant find if the motherboard 3.3v DX2 66 is a great choice. It was the minimum system requirement for games for years

In terms of speed, the DX2-66 might be exactly the same as my current SX2-66, the only difference would be the FPU

chinny22 wrote:

DX2 66

Ayup. Make sure it's 5V though.

For anything not running well on a DX2/66, a Pentium system would be the better option anyway.

Elia1995 wrote:

In terms of speed, the DX2-66 might be exactly the same as my current SX2-66, the only difference would be the FPU

Opps my mistake!
I kept reading SX2 as SX25
Doom will play better as mentioned before. otherwise cant think of any other good reason.
You will be able to play games like Duke3d but still not what I call enjoyable

I tried Duke3D and it lags like crap 🤣

Doom is already playable even on this SX2 though...

Elia1995 wrote:

If I can afford/find one to buy :\

A Pentium Overdrive would be even better at that point, or not ?

Or a Kingston Turbochip or that Evergreen Socket 3 upgrade (I forgot the exact names). There was also Gainbery. Those might be tricky as well though (to find and to use), but if you happen to see one for sale for cheaps, might as well get it 😁

Elia1995 wrote:

That's interesting... the e-mail link redirects me to olivetti.com which looks dead...

Yup, that's interesting indeed. I got redirected to :

http://www.olivetti.com/IT/Page/t03/view_html?idp=146

And this page works fine here. Maybe that's because I use Firefox ?

Anyway, If that doesn't work for you, you can also try the original homepage at olivetti.it.

I made a thread on that forum you linked me yesterday: http://www.motherboards.org/forums/viewtopic. … hp?f=2&t=123287

He linked me two manuals of two motherboards, the second says has almost the same specs as mine, but it's different, those ones don't have the regulator jumpers, but none of them is the same model as mine, so.... I dunno ???

Any progress on this matter? I've got a 486 SX2 50 from Olivetti and I could not find anything on this motherboard on the internet.

I don't dare to replace the sx2 50 with the dx2 66 I have without knowing which jumpers to set, not that I switch off the wrong jumper and fry the computer (would not be the first time).
Only found out by myself the jumper for external videosource, near the onboard video. This is as far as I went.
Any hints? I went on sason.org but did not find this motherboard there nor anywhere on the internet.

This motherboard looks oddly clean to me. Where are the usual (SMD) resistors?