486 cpu question

[scourge]

I bought an intel cpu out of a garbage bin for a $1 today. It was marked 486dx-50. Is this chip a straight up 486-50 that runs at 50 bus or is it a dx2 that runs at a 25 bus. I expected it to be marked 486dx2, but it wasn't. Were there ever any straight up 486-50s? I can't get it to run at anything over 33 in my mobo. Probably because I have no documentation for this **** thing and I can't find the manual for it on the net. It's a gigabyte board 486vm. Can someone point me in the right direction? Thanks.

[LJE2]

I don't remember any 486 motherboards with a 50 MHz bus, I do recall the 75 MHz pentium used a 50 MHz bus and a 1.5 multiplier, and this is the first I recall seeing a 50 MHz Bus (The DX/2 50 as you state was a 25 MHz bus, the DX/2 66 was a 33 MHz bus)

[800XL]

If it says DX it is a 50mhz bus 50mhz core speed 486. If it says DX2 then it is a 25mhz bus 50 mhz core chip. Those things are actually fairly rare. Intel had a hell of a time getting DX chips to yeild up to 50Mhz core speed for quite a while and the problems that could sometimes creep up with peripherals sorta pointed them towards DX2s. If you do nothing else with it, hang on to it for a couple decades and sell it as a collector's item. It should run on any board with a 50Mhz bus, but watch any VLB cards for problems at that speed. You should be able to set the board to 1 wait state and asyncronous VLB speed and it will be fine. Also those chips got pretty hot so a heatsink would not be a bad idea.

[cobain1crt]

My 486 mobo did the 50mhz, bus, an easy overclock for a 40mhz AMD.

[sjs74]

I had a straight DX-50 for several years and my friend's grandpa is running it now. I never had a problem with it. It didn't even have a heatsink on it and didn't have problems, although it did get hot to the touch.

[aratike]

I'm going to go off on a tangent and ask a quick question. What does the DX-4 designation stand for? My mom's Packard Hell is a 100mhz 486 DX-4 and I have always wondered about that "DX-4"....

[sjs74]

I think the DX-4 was originally so they could copyright the name since it made no logical sense. A DX-4 CPU is actually clock tripled, not quadrupled as the name would imply. So your mom's DX4-100 is running on a 33 MHz bus with a 3x multiplier, with the 120's (AMD) running at 40x3.

[KillerBug]

Um...I had a DX-4 100 that ran on the 25mhz bus. I wonder if they made a DX-4 that run on the 50mhz bus! Even if intel made it, still 150mhz. By the way, DX2 on 33mhz bus=no heatsink or fan.

[Stevo]

I had a dx2-80, - 40mhz bus

The previous owner o/ced it, and it read dx4-100 mhz on startup, - 25mhz bus?

so thats cool, but sisoft says that it has a 33mhz bus and a 3x multplyer = 99mhz

Anyone know whats going on here

[steves]

Stevo~I would have assumed it was o/c at 2*50Mhz, I tried this with my DX2-80 but it would never run for more than 2 minutes (but others have done it).

As 2*50 was never a original setting both the BIOS and sisoft could be confused and lying. Although if it was a late DX2-80 there is a chance it supported the *3 and could be running at 3*33 (less bus speed problems that way). Best way to find out for sure is to check the jumper settings (assuming you have manual, can find them on the web, or they are on the board).

[aratike]

I had the case off of Ma's PC and noticed that the "authorized" Packard Hell service shop (I bet they had lots 'o work) actually overclocked it! The mobo had gone out and it came back at 100mhz - slightly higher than the original 75... I wonder if that was a factory authorized tweak?!?! Guess I won't be overclockin that one.