SX and DX are as fast in non-FPU operation.
As you said, DX will allow you to run FPU dependent stuff.
Quake will never be enjoyable on a 486, nor pretty much anything else gaming-wise that needs a FPU.
But the added 33MHz of the DX4 will help in any case, so if your motherboard can take it (DX4s are 3.3V, DX2 5V, could be a problem), why not ?

DX or SX doesn't really matter until you start using programs/games that rely on a FPU. Games like Doom won't run faster on a DX. Games like Quake require that you have a FPU but since Quake requires a faster CPU (a Pentium 90/100 is nice for low-res) it won't be a succes on a 486 after all.

Besides the SX/DX difference you have another, more important difference, which is the multiplier. The DX/4 will run at a higher clock frequency which will improve performance quite a bit 😀.

Are both on the same Socket 3 anyway ?
I also have a Pentium '92/'93 but I dunno what socket it is for as I have no idea how to search for that particular Pentium.

The Pentium won't work as it's going to be Socket 4,5, or 7.
But sounds like it might be a cool processor, what's the model number?

For socket 3 and pentium, there's the Overdrives (and only the Overdirves)

keenmaster486 wrote:

The Pentium won't work as it's going to be Socket 4,5, or 7.
But sounds like it might be a cool processor, what's the model number?

I'm reading from below it:

A6043284BF PHILIPPINES

A80502100 SY007 / SSS iPP

On top there is a sticker with some numbers and the 4 crossed out and a 350 handwritten with a marker.

All of that about the Pentium.
Ah and I have 2 of them, exactly identical.

I'll upload the photos when I'm home.

Ah, so it's a P54C 100 mHz Socket 5 job, if I'm not mistaken.

I wonder where I can get a motherboard for them…

Now I'm going home and I'll try that DX4-T100

Elia1995 wrote:

I wonder where I can get a motherboard for them…

Any Socket 5 or 7 MB will work, they're pretty ubiquitous.

Elia1995 wrote:

Now I'm going home and I'll try that DX4-T100

That's gonna be cool 😀

Make sure your motherboard can deliver 3.3v before.

Ok, I inserted the 486DX4-T100, but when it boots, the PC tells me that it is a 486DX2, is it normal ? Will it burn the CPU later on ? Are there some jumpers to move perhaps ?

The CPU is EXACTLY like this one:

sunaiac wrote:

Make sure your motherboard can deliver 3.3v before.

How ?

EDIT: browsing on Google, I just read something that quite scared me... I read that a 5v voltage can kill the processor, well that was obvious, but I also relieved reading that exist some converters that go between the socket and the processor that can convert the voltage from 5v to 3.3v... only problem is that I searched for them on eBay and I could find NONE. Where can I get one ?

I turned on the PC only 1 time, when I saw that it got detected as a DX2 instead of DX4 and I then shut it off, I never turned it on again... well, the CPU is working it seems, but why is it being detected as a DX2 ?

Elia1995 wrote:

How ?

Check jumper settings on the board and compare them to the ones printed in the mainboard manual.

I have no manual for that built-in motherboard, there are no jumpers at all and I have no idea what is the model number of the motherboard to search on Google... even just browsing "Olivetti M4 434S" gives me no useful info 😕

On the edge of the motherboard I can read what I think is the model number: P.C.B COD.654296A/00 A-S-F94 but I find NOTHING on Google.

I know a source of voltage converters but they are Expensive and one can almost buy a socket 3 pci board for the same cost, in the same boat as you and came to the conclusion that it just wasn't worth it despite having a cyrix 5x86.

Now it's time to provide some photos, maybe with the photos you can find out where the voltage regulator jumpers are and how they should be set (I can't find any manual on Google)

Here's the "fresh" 486DX4-T100 in the Socket 3:

Here are some close-ups of the other parts of the "reachable" motherboard:

There are some blue jumpers here:

Here's where I read the model of the motherboard:

I probably won't keep this cooler: I can't fix it anywhere and I'm afraid it could move off sometimes...

This looks suspicious, maybe that's what regulates the voltage ?

nforce4max wrote:

I know a source of voltage converters

Where ?

I don't know if the seller ships to Europe, $45 usd shipped and no its not on eBay.

Elia1995 wrote:

I have no manual for that built-in motherboard, there are no jumpers at all and I have no idea what is the model number of the motherboard to search on Google... even just browsing "Olivetti M4 434S" gives me no useful info 😕

On the edge of the motherboard I can read what I think is the model number: P.C.B COD.654296A/00 A-S-F94 but I find NOTHING on Google.

Found this: http://www.motherboards.org/forums/viewtopic.php?t=39515

Seems the Olivetti has a "BA2161" mainboard.

That thread wasn't very much useful... I mean, I couldn't find the manual there and even searching BA2161 doesn't lead me to the manual 😕

True. You could contact one of those users, though. The dude that provided the manual mentions an email address (two, actually)..
No idea if that's a good idea or if that address is still valid, but it's a start.

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

I'm not saying what you should do or not, though.
These are just proposals.