DX4 at 2x is faster than a DX2, due to 16KB L1 cache compared to 8KB of DX2, it won't be the authentic experience you seek.

interesting consideration, then I will have to test both cpus. could a dx4 in wt be equal to a dx2 in wb? my mainboard seems only work in wt

It is not something I have tested, someone else will have to chime in about what the difference is.

I have tested on speedsys 4.78
DX4 at 100Mhz = 39,43
DX4 at 66Mhz = 28,27
DX2 at 66Mhz = 25,06

it is a notiveable difference in real use? Games, S.O. ecc?

sidenote: without teaking off the dx4 regulator, the dx2 work apparently perfect (at 3v instead of 5v) , it finish Doom and quake benchmark and (very strange) the regulator on the heatsink remain absolutely cold, with the dx4 instead become very hot in 66mhz and even in 100mhz settings… why???

Dx2 at 3v ??? danger....

didin't you change the jumper for voltage ? or do your bios autometic detects the voltage ?

undervoltage is more dangerous than overvoltage

the is a regulator pcb that can be removed… why it is more dangerous? other people tell me the opposite… i’m confused..

May you post a picture of ALL your DX2's please? (DX4's are also welcome)

here the link

https://drive.google.com/drive/folders/1-KiNs … wtDnSOd4xzXPy3W

i have try to power on the pc without the regulator (you see the socket at the right of the cpu) and without the jumper strip to make short circuit and the system work perfect. very strange also that…why? tnks

The 486DX2 on picture 4265 is a SX807 It has SL support and the CPUID instruction but no write back.

and what means? support 3v?

Only DX2s that support 3V are AMD and Cyrix AFAIK..

AlessandroB wrote on 2021-11-03, 16:45:

the is a regulator pcb that can be removed… why it is more dangerous? other people tell me the opposite… i’m confused..

Under voltage is never dangerous to the CPU

If the cpu is unstable at the lower voltage that is a potential way to corrupt HD data, freeze, lockup, etc.

Poster is mis-informed

rmay635703 wrote on 2021-11-03, 17:15:

Under voltage is never dangerous to the CPU […]
Show full quote

AlessandroB wrote on 2021-11-03, 16:45:

the is a regulator pcb that can be removed… why it is more dangerous? other people tell me the opposite… i’m confused..

Under voltage is never dangerous to the CPU

If the cpu is unstable at the lower voltage that is a potential way to corrupt HD data, freeze, lockup, etc.

Poster is mis-informed

that's what I've always known too, but in this forum you are all monsters of knowledge and everything

what can you tell me about the fact that it works without regulator and without short-circuiting the regulator pins on the mainboard?

AlessandroB wrote on 2021-11-03, 17:24:

rmay635703 wrote on 2021-11-03, 17:15:

Under voltage is never dangerous to the CPU […]
Show full quote

AlessandroB wrote on 2021-11-03, 16:45:

the is a regulator pcb that can be removed… why it is more dangerous? other people tell me the opposite… i’m confused..

Under voltage is never dangerous to the CPU

If the cpu is unstable at the lower voltage that is a potential way to corrupt HD data, freeze, lockup, etc.

Poster is mis-informed

that's what I've always known too, but in this forum you are all monsters of knowledge and everything

what can you tell me about the fact that it works without regulator and without short-circuiting the regulator pins on the mainboard?

Don't believe everything you see/read on the internet For example so called "experts" that have no idea what they are talking about and computer history revisionists are everywhere.

Caluser2000 wrote on 2021-11-03, 17:35:

AlessandroB wrote on 2021-11-03, 17:24:

rmay635703 wrote on 2021-11-03, 17:15:

Under voltage is never dangerous to the CPU

If the cpu is unstable at the lower voltage that is a potential way to corrupt HD data, freeze, lockup, etc.

Poster is mis-informed

that's what I've always known too, but in this forum you are all monsters of knowledge and everything

what can you tell me about the fact that it works without regulator and without short-circuiting the regulator pins on the mainboard?

Don't believe everything you see/read on the internet For example so called "experts" that have no idea what they are talking about and computer history revisionists are everywhere.

i do not believe everithing but Vogoms seems a a place of knowledge.

About my question???

What's with the Vcc5 pin on your CPU (pin J1)? Is it the same like the Vcc pins? Or do you a get a different behaviour when comparing your measurement to one between tow Vcc pins?
486 pinout comparison

I've got an Intel DX2 66 SL/WB that's rate for 5v. Three actually. They run fine at 3,3v.

The older non-SL WT DX2 will post but hangs at Himem while booting. No go.

The even older one won't even give me image at 3,3v.

All tested extensively and it never gave any hardware problems (except for the mentioned instability).

Lower voltage on the CPU will only increase expected lifespan.
So if your DX2 will run stable at 3,3v there's no reason not to. Nothing will break or short.

AlessandroB wrote on 2021-11-03, 10:27:

Anonymous Coward wrote on 2021-11-03, 05:07:

If your CPU is Cyrix/TI/IBM/ST, then it's possible that the speed is being misreported if the program in question isn't designed to properly identify it. Speedsys for example detects my 40MHz 486SXL as 13MHz despite the fact it runs at 40.

no it is the genuine dx4 intel installed by imb in the 1995 in this pc

I assume you have pulled the CPU out and checked it right? IBM had an agreement with Cyrix around 1994 or so, and from what I recall they usually used the Cyrix based IBM branded DX4 in their PCs. The Cyrix based ones usually had a anodized blue heatsink with IBM stamped on it, and a black bottom.

Anonymous Coward wrote on 2021-11-04, 14:23:

AlessandroB wrote on 2021-11-03, 10:27:

Anonymous Coward wrote on 2021-11-03, 05:07:

If your CPU is Cyrix/TI/IBM/ST, then it's possible that the speed is being misreported if the program in question isn't designed to properly identify it. Speedsys for example detects my 40MHz 486SXL as 13MHz despite the fact it runs at 40.

no it is the genuine dx4 intel installed by imb in the 1995 in this pc

I assume you have pulled the CPU out and checked it right? IBM had an agreement with Cyrix around 1994 or so, and from what I recall they usually used the Cyrix based IBM branded DX4 in their PCs. The Cyrix based ones usually had a anodized blue heatsink with IBM stamped on it, and a black bottom.

there us the heatsink glued on, but the system say me “intel”, i not think IBM sell a cyrix cpu for a intel one.

waterbeesje wrote on 2021-11-04, 13:12:

I've got an Intel DX2 66 SL/WB that's rate for 5v. Three actually. They run fine at 3,3v. […]
Show full quote

I've got an Intel DX2 66 SL/WB that's rate for 5v. Three actually. They run fine at 3,3v.

The older non-SL WT DX2 will post but hangs at Himem while booting. No go.

The even older one won't even give me image at 3,3v.

All tested extensively and it never gave any hardware problems (except for the mentioned instability).

Lower voltage on the CPU will only increase expected lifespan.
So if your DX2 will run stable at 3,3v there's no reason not to. Nothing will break or short.

mine is SL but not WB but WT.