Remember that your upgrade options will require a cooler and probably a fan too. A 486/33 won't need cooling.

There do exist 486 overdrives (ODPR) that will take 5 volts.
486/66 is suitable for 5 volt too.

But with a DX4 you should first take care whether your board supports your CPU in write back mode or not. If you cannot run L1 in WB mode, don't expect too much performance increase anyway.
However, there do exist adapters that can provide 3.3 volt.

Disruptor wrote on 2022-12-13, 22:02:

Remember that your upgrade options will require a cooler and probably a fan too. A 486/33 won't need cooling. […]
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Remember that your upgrade options will require a cooler and probably a fan too. A 486/33 won't need cooling.

There do exist 486 overdrives (ODPR) that will take 5 volts.
486/66 is suitable for 5 volt too.

But with a DX4 you should first take care whether your board supports your CPU in write back mode or not. If you cannot run L1 in WB mode, don't expect too much performance increase anyway.
However, there do exist adapters that can provide 3.3 volt.

Gotcha, thanks for the reply. Yeah, that thing sitting there bare just brings me back!

I think I'll go the 486/66 route if I can source a CPU for a decent price. Just always recalled wanting the DXs back in the day (built-in math-coprocessor).

Maybe it wont mean much playing some old games, which is the primary reason for the rig.

I think the CF card and 32MB of ram (it has 8MB now) will make much more of a difference.

There are overdrives with x2 (DX2) and x3 (DX4) clock.
There are also overdrive kits that allow x4 operation (adapter with an AMD processor).
There also exist some DX2 processors with integrated cooler but no fan.

Your mainboard seems to have a PS/2 mouse port plus the capability of taking 1 MB L2 cache and to operate L1 in WB too.
The manual you can download from ASUS shows that your board should support 3,3 V -- why do you think it would not?

Socket 1/2/3 Voltage Interposer Tweaker (Alpha)

This is designed to adapt 5v to 3.3v if needed.

Disruptor wrote on 2022-12-13, 23:52:

There are overdrives with x2 (DX2) and x3 (DX4) clock. There are also overdrive kits that allow x4 operation (adapter with an A […]
Show full quote

There are overdrives with x2 (DX2) and x3 (DX4) clock.
There are also overdrive kits that allow x4 operation (adapter with an AMD processor).
There also exist some DX2 processors with integrated cooler but no fan.

Your mainboard seems to have a PS/2 mouse port plus the capability of taking 1 MB L2 cache and to operate L1 in WB too.
The manual you can download from ASUS shows that your board should support 3,3 V -- why do you think it would not?

Yeah, many options it seems. I found what looks like a new DX4-75 which should work on the board according to the manual (can't say how impressed I am that Asus had this on their site still, albeit short some pages). I think I am going to give it a go

I had found this post here that made me think that the X4 version of the board was the one that supported 3.3v (while my version did only 5v).

Sphere478 wrote on 2022-12-14, 00:47:

Socket 1/2/3 Voltage Interposer Tweaker (Alpha)

This is designed to adapt 5v to 3.3v if needed.

Quite interesting indeed, I might not have a need but great to know!

Blastoid wrote on 2022-12-14, 02:59:

Yeah, many options it seems. I found what looks like a new DX4-75 which should work on the board according to the manual (can't say how impressed I am that Asus had this on their site still, albeit short some pages). I think I am going to give it a go

I had found this post here that made me think that the X4 version of the board was the one that supported 3.3v (while my version did only 5v).

The manual in the ASUS site is for the X4 and that version is indeed the only one that supports voltages other than the standard 5V. The non-X4 is just a cost reduced version without regulator. That means if you want to run a DX4 or any other CPU that runs at < 5V you need either an Overdrive or an interposer with a voltage regulator.

However, the non-X4 can be easily converted to X4 by adding a voltage regulator and a few other components if you have some basic soldering experience. In fact, there is a white sticker covering the "X4" in the name of the board that you can remove! I made a thread about converting my own board (rev. 1.8 ), while other users have also created their own considering there are slight variations between revisions. If you are interested in doing this I can point you to one of those threads.

EDIT: also, those DX4-75s are PQFP, probably intended for laptops, embedded systems and such. What you need is a CPU in the standard PGA ceramic package for Socket 3.

Uh, a DX4-75 is seldom better than a DX2-66.
And those DX4 don't have L1 cache that is operating in WB mode.

TheMobRules wrote on 2022-12-14, 04:08:

The manual in the ASUS site is for the X4 and that version is indeed the only one that supports voltages other than the standard […]
Show full quote

Blastoid wrote on 2022-12-14, 02:59:

Yeah, many options it seems. I found what looks like a new DX4-75 which should work on the board according to the manual (can't say how impressed I am that Asus had this on their site still, albeit short some pages). I think I am going to give it a go

I had found this post here that made me think that the X4 version of the board was the one that supported 3.3v (while my version did only 5v).

The manual in the ASUS site is for the X4 and that version is indeed the only one that supports voltages other than the standard 5V. The non-X4 is just a cost reduced version without regulator. That means if you want to run a DX4 or any other CPU that runs at < 5V you need either an Overdrive or an interposer with a voltage regulator.

However, the non-X4 can be easily converted to X4 by adding a voltage regulator and a few other components if you have some basic soldering experience. In fact, there is a white sticker covering the "X4" in the name of the board that you can remove! I made a thread about converting my own board (rev. 1.8 ), while other users have also created their own considering there are slight variations between revisions. If you are interested in doing this I can point you to one of those threads.

EDIT: also, those DX4-75s are PQFP, probably intended for laptops, embedded systems and such. What you need is a CPU in the standard PGA ceramic package for Socket 3.

Thank you! Yeah your post is what got me thinking that the X4 was required for 3.3v as it wasn't clear to me in the manual.
Based on the responses here I think I'm going to try to find a DX2/66 to keep things simple and get a performance boost over the SX/33. I'd rather not mod the board if not needed as it took me a while to find this rig at a decent price ($130 on FB, full working desktop with no monitor).

Disruptor wrote on 2022-12-14, 04:10:

Uh, a DX4-75 is seldom better than a DX2-66.
And those DX4 don't have L1 cache that is operating in WB mode.

Did not realize this, might have known back in the 90s but that's why I'm here (to relearn a few things). Thank you for the info, I think I'm going to push for a DX2/66.

Blastoid wrote on 2022-12-19, 15:44:

Disruptor wrote on 2022-12-14, 04:10:

And those DX4 don't have L1 cache that is operating in WB mode.

Did not realize this, might have known back in the 90s but that's why I'm here (to relearn a few things). Thank you for the info, I think I'm going to push for a DX2/66.

I meant those SK052 DX4-75's on ebay you posted.
Check the S-Spec numbers on cpu-world.com first!

Disruptor wrote on 2022-12-19, 20:35:

Blastoid wrote on 2022-12-19, 15:44:

Disruptor wrote on 2022-12-14, 04:10:

And those DX4 don't have L1 cache that is operating in WB mode.

Did not realize this, might have known back in the 90s but that's why I'm here (to relearn a few things). Thank you for the info, I think I'm going to push for a DX2/66.

I meant those SK052 DX4-75's on ebay you posted.
Check the S-Spec numbers on cpu-world.com first!

Thanks for clarifying, that'd explain the price 😁