Overclocked from factory?

[per]

I got a minitower with a ECS FX3000 UL486 Rev. 1 Motherboard and a 25MHz clock. What recently noticed that the Processor was a A80486SX-20, and that processor came with the computer when it was new.

I don't know if the ECS FX3000's turbo actually reduces the physical clock speed, or if it uses some other slowing technice like clearing the cache.

I don't want to overclock the processor, and I can't guarantee if I can disable turbo to solve the problem.

What should I do?

 

[modem7]

How do you know that the clock to the CPU is 25 MHz ?

Looking at the details of that board on Total Hardware 99, 'Processor Speed' can be "16/20/25/33/40/50(internal)/50/66(internal) MHz", and there are no switches/jumpers that affect clock. So that suggests that clock speed is altered by changing the oscillator unit, or perhaps a setting in the BIOS setup.

 

[per]

How do you know that the clock to the CPU is 25 MHz ?

Looking at the details of that board on Total Hardware 99, 'Processor Speed' can be "16/20/25/33/40/50(internal)/50/66(internal) MHz", and there are no switches/jumpers that affect clock. So that suggests that clock speed is altered by changing the oscillator unit, or perhaps a setting in the BIOS setup.

There is a panel on the front of the computer displaying 25 MHz, the bios state it's a 25MHz 486SX installed, and the oscillator unit has "25MHz" printed on it.

I have seen in the BIOS dump, and there is some text about different clock speeds, but the option is just not showung up when BIOS Setup is run... Maybe the function is disabled somehow.

Anyway, I have pulled the processor and placed a bid on a 486sx with the right speed on Ebay. (The seler has placed it on the kind of black foam chips normally are placed on when they're out of the socket)

 

[Anonymous Coward]

Unknowingly buying an overclocked 486 back in the day was certainly possible. It happened sometimes with 8088 and 286 systems.

I wouldn't worry too much about the 20MHz part burning out. It's pretty much the slowest 486 you can buy, and they're probably all underclocked by intel anyway. I'd be surprised if 25MHz was the best it could do. Many of the 25MHz parts easy did 33MHz.

 

[per]

I wouldn't worry too much about the 20MHz part burning out. It's pretty much the slowest 486 you can buy, and they're probably all underclocked by intel anyway. I'd be surprised if 25MHz was the best it could do. Many of the 25MHz parts easy did 33MHz.

I know... But I really can't stand when something isn't 100% right

For additional ifo on the PC, it was assembled in a local PC store (Named "TCI") in Bergen sometime around 1993 (they're still in existence).

The PC has:
-A GoldStar (GM82C765B) based FDD/HDD adapter (16-bit ISA Labbeled "IDE v2")
-A Winbond (W86C450, W86C451, W86C456A) based Serial/Parallel adapter (8-bit ISA labbeled "ATIO v8")
-An OPTi 931 (SoundBlaster 16 compatible) Sound Card (16-bit ISA)
-A TSENG (ET4000AX) based VGA adapter (16-bit ISA)

-HITACHI CD-ROM
-TEAC 5.25" FDD
-3.5" FDD
-116MB HDD
-AT compatible PSU
-turbo/reset buttons

 

[Anonymous Coward]

Looks like a pretty typical clone, though it is a little strange that your I/O is not integrated onto the Goldstar card.

Also, your OPTi card would probably be SB or SB Pro compatible. I don't believe there are any cards that can emulate the SB16.

 

[carlsson]

I have a later, 16-bit ISA OPTi sound card that I think includes SB16 emulation with the right drivers. It even has a built in wavetable and can produce quite sophisticated MIDI music, even better with an expansion. Unfortunately (?) the last set of drivers were for the Windows 95/98 generation, so at one point I had to abandon it for day to day work.

 

[per]

Just got my new 80486SX-25 today (I can't imagine why you have to use so much force to get them out of the socket when they slips right in on mounting!). It seems to work all-right.

BTW, I just examined the system bus:
6 * ISA 16-bit
1 * EISA
1 * ISA 8-bit (!!!)

However, the EISA slot is partly covered by the hdd, so it can only be used as a Half-Lengt ISA 16-bit slot. The chassis provides Full-length supports for 7 of the cards (minus the one partly covered by the HDD).

*Edit*
The PSU is a ZECK ZKS-520T 220W, and the HDD is a CONNER CP30104H

 

[IBMMuseum]

...BTW, I just examined the system bus:
6 * ISA 16-bit
1 * EISA
1 * ISA 8-bit (!!!)

However, the EISA slot is partly covered by the hdd, so it can only be used as a Half-Lengt ISA 16-bit slot. The chassis provides Full-length supports for 7 of the cards (minus the one partly covered by the HDD).

*Edit*
The PSU is a ZECK ZKS-520T 220W, and the HDD is a CONNER CP30104H

And I think you will find that is an Opti Local Bus slot, not EISA. For just a single slot EISA stops becoming a viable option - The reason to have a setup utility, etc. is for multiple adapters. There was a few different display adapters for the Opti Local Bus, not much more.

 

[TNC]

You`re right. Some Boards had 8 Bit Slots, because some ISA Cards are not physically pluggable into 16 Bit Slots. For example, I have such a Hercules Graphics Adapter.

 

[per]

And I think you will find that is an Opti Local Bus slot, not EISA. For just a single slot EISA stops becoming a viable option - The reason to have a setup utility, etc. is for multiple adapters. There was a few different display adapters for the Opti Local Bus, not much more.

It's actually a VESA slot.