Anyone know how to oc a 486?

B

best [486]

Limp Gawd
Joined
Aug 28, 2005
Messages
476
I just want the best 486. It's already watercooled :D :D :D [no radiator] anyone know where i can get a very cheap radiator?
once i oc it it'll be my server [1GHz+ :) ]
 
Taking for granted you are not joking....

I've OC'd quite a few 486 systems many moons past. What board and CPU have you got to work with?
 
well, with a locked fsb of 33 mhz, youd need a multiplier of 31x to get 1 ghz
good freakin luck

/thread needs to be locked
 
rofl, I wanna' see a 486 hooked up to a phase change unit :D

I wonder how far that would overclock...and how it would compair to current processors (once they were underclocked to match the 486's overclock)
 
I'm not kidding. I want a newer mobo [pci,72-pin memory]. anyone know where I can get one [not ebay]. I don't care if i have to try to make a new bios { I bet I could figure it out], I just want to overclock.
 
best [486] said:
I'm not kidding. I want a newer mobo [pci,72-pin memory]. anyone know where I can get one [not ebay]. I don't care if i have to try to make a new bios { I bet I could figure it out], I just want to overclock.
Click to expand...
I have one sitting on a table in my front yard. If you're near Sacramento/Auburn CA come get it. :)
 
Easy way to oc 486 is to set the fsb from 33mhz to 40mhz with a dx4 100 would net ya 120mhz. Make sure your motherboard is pci not vesa else your stuck at 33 bus
 
Well in the past I just simply changed jumper settings and then vioila 33 @ 66Mhz !!! Take that Packard Bell!!!
 
if you are serious...

back in the day, the 486 boards would have jumpers to set fsb. a really good 486 board would have 20/25/33/40/50 mHz settings, but alas no multiplier. that was done internally within your CPU thus the DX2, DX4 CPU's and the good ol AMD 5x86 which i pushed to 160mHz lol

as far as i can remember the CPU would be "hard wired" with the multiplier set, and you could only change the FSB, but then again it was sooo long ago...i just dont remember ever seeing a multiplier jumper block on any 486 motherboard
 
486s multiplier can be changed via jumper settings.

As xxGriff said the FSB on good boards had settings up to 50 Mhz. The 25 33 and 40 Mhs settings run the PCI bus at a 1:1 ratio. The 50 Mhz setting runs the PCI bus at 2/3ds the speed = 33Mhz.

I found the 40 Mhz to be more effective as the extra Mhz for the PCI bus gave a better overall performance boost. The HD has to be one that can hand 40 MHZ though.

You could also OC the older Vid Cards using a program called MCLK.

I had my AMD 5X86 133Mhz chip @ 40X4=160Mhz (P1 HSF) with the S3 vid card OCd from 50 to 83 Mhz with the old HSF! :D this gave better performance than 33X5=166 Mhz. You had to add the extra meg of RAM to those old vid cards to get the full mem bus width or somthing, otherwise you lost half the performance. Used to beat the early P1s with that machine and piss my rich friends off no end. :D

Upping the voltage was unknown to me in those days but you could probably up the voltage from 3.3V? to 3.5V? without problems. Especially with water cooling. Might get 200 Mhz from a 5X86 chip!
:)

O yea: you can OC the ISA bus in the bios by changing the devider to /4 for 40Mhz etc. go for 10 to 12 Mhz. (8 Mhz std.) L2 cache can also be upgraded to 512 KB by swiping the SRAM and the one TAGRAM chip/s of an old P1 board. Go for the fastest ones you can find. Set the L2 to write back?, rather than write through? for better performance. and lower your latencies as far as possible. Memtest seems to burn in that old EDO RAM very well.

(the question marks are for things I'm not sure about any more. Memory's a bit rusty. :) )
 
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