sombunall
Experienced Member
http://en.wikipedia.org/wiki/List_of_Intel_microprocessors
What kind of marketing shenanigans is this? I don't understand... and what about Weitek? My first computer had a slot for a Weitek but I never got one.
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Most uncommon 486 chips
- Thread starter Unknown_K
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http://en.wikipedia.org/wiki/List_of_Intel_microprocessors
What kind of marketing shenanigans is this? I don't understand... and what about Weitek? My first computer had a slot for a Weitek but I never got one.
krebizfan
Veteran Member
Intel had reportedly poor yields on the early 486; many of the math parts did not work. The 486SX let them sell the defective chip after disabling the part that failed.
I think a seperate coprocessor would have been much slower than using a combined chip. With a lot of 486 motherboards, the cheapest and easiest way to upgrade was to pull the 486SX chip and install the 486DX in that socket; ignoring the putative upgrade socket. The upgrade socket sounded better in theory than practice but Intel kept plugging away at it. While the second socket upgrades never took off, it did lead Intel into improving socket designs that made it simplified chip insertions.
Weitek was a third party company that made it's own coprocessors. For programs that specifically supported them, the performance boost was greater than with a normal x87 coprocessor. Your board also had to specially support them - I think - but I could easily be wrong on this. Weitek copros were mostly a 286-386 era thing, and were mostly gone by the 486 era, so I'm not too familiar.
I have a 486 era Weitek chip, they needed a special socket much bigger then the 386 era FPU. The motherboard BIOS will allocate RAM for the Weitek to use (256k?). They are supposed to be a bit faster then the FPU of a 486DX/25 but once you get into the 486/66 or higher they are not competative and were dropped from boards.
sombunall
Experienced Member
Oh I get it now. They didn't want to force people to buy chip pullers. Too obvious.
I worked for Qualitas (386MAX Windows support) at the time those came out. We had a pretty good relationship with Intel. At the announcement ofr the 486SX they gave out nice leather notebook thingies. We joked if they spent more on the leather handouts than they did engineering the chip. The Intel guy laughed and said "No, we got a good deal on the notebooks." ;-)
Bill
Dave Farquhar
Experienced Member
Part of it, too, may have been that people who wanted math coprocessors were used to buying a separate chip and plugging it in. That's the way it had been for 10 years, after all. The built-in coprocessor was one of the 486's, er, 486DX's big selling points, but of course not everyone got the memo right away. It took a couple of years for the general computer-buying public to get used to the idea of the math coprocessor being built into the CPU.
I doubt very many people went and bought a 486SX and then immediately bought a 487 and plugged it in, but it wouldn't surprise me at all if a small number of people did it. Which allowed Intel to sell two expensive CPUs instead of just one, and I'm sure Intel didn't mind that at all.
But as for those chip pullers, I remember the so-called LIF socket, which was supposed to stand for Low Insertion Force. I had to do some CPU swaps on those machines. I insisted that LIF really stood for LOTSA Insertion Force.
johnorun
Experienced Member
I have removed dozens of heatsinks and the stubborn ones to remove are almost always glued on with EPOXY.
Trying to remove an EPOXY-bonded heatsink from a chip by inserting a knife blade, screwdriver or hammer and chisel (I've tried them all) results in damage :bomb: to the chip or the print surface about 90% of the time. Through trail & error I found that aiming a heat gun (600-800F) at the top of the heatsink for a minute or two will weaken the strong EPOXY enough that you can slowly twist (not pull) the heatsink off. I use a "ViceGrip" pliers to *gently* hold the chip edges while twisting the heatsink with another wide-jaw pliers.
Try to clean any remaining EPOXY residue off the chip while it's still warm. The EPOXY seems to crumble off when scraped with a sharp chisel or other metal edge. (Watch that the print doesn't get removed in the process.)
Finally, now admire your work...:D
Good Luck!
I find almost all of the P60, P66 chips I seen have the epoxy glued on heatsink with no fan. Took me ages to find a P60 chip that wasn't glued to the heatsink for my collection. Havn't realy noticed that many 486s with that problem except for a few Cyrix ones with the green heatsink (which I would have left on anyway).
I've pried epoxy'd heatsinks off with a flathead screwdriver without hurting the chip before - the key is to turn the screwdriver once you've got it wedged in, instead of prying, so that the a bunch of force doesn't get released all at once and make you lose control.
Anonymous Freak
Veteran Member
The other use for the socket was for systems where the 486SX was soldered down. I have one that way, with a soldered down 486SX, and a socket for a full-blown 486. (Although in my case, it doesn't appear to be a "487" socket, but a standard 486 socket.)
Tetrium
Experienced Member
I'm not too unfamiliar with rarities of socket 3 chips, but a couple days ago I got a chip I didn't even know existed. An AMD SX2-66!
I know it's not uber rare but it's certainly not common, right?
I know it's not uber rare but it's certainly not common, right?
http://en.wikipedia.org/wiki/File:KL_AMD_486SX2.jpg
They exist, I never seen one unless I didn't notice the S.
deathshadow
Veteran Member
- Joined
- Jan 4, 2011
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Little known fact -- all of the AM5x86/133's are in fact the exact same chip as the 150... there is NO mechanical difference even under testing.
The AM 150 required a 50mhz FSB, which the majority of 486 motherboards didn't support -- since the DX2/66 and even the DX2/50 pretty much spelled the doom of the DX50... So they didn't have to deal with people complaining that their motherboard didn't work at the advertised speed, they went with the 4x multiplier at 33 as the 'advertised' speed, but if you got one with the datasheet it did explain that if your board supported 50mhz FSB, you could run a 3x multiplier at 150 just fine... They just decided the wiser of advertising it or labelling it as such.
Biostar saw a brief spike in sales back in the day since they made the cheapest board that supported the DX-50, since at 150mhz the AM5x86 ends up delivering about the same performance as a P90 and cost a fraction the price. Hell, the "pentium overdrive" chips cost more than a biostar board and a am5x86/133 COMBINED.
Dave Farquhar
Experienced Member
I'm way late to the AMD 486SX2/66 discussion, but yes, they exist. My first 486 was one of those. Compaq wanted to sell a 66 MHz SX2, so they went to AMD and asked them to produce it. Later AMD sold it to other suppliers too, other than Compaq.
Mine was in a low-profile Presario. Would you believe I paid almost $1300 for that machine in 1994? 486SX2/66, 4 MB of RAM (expandable to 56 MB), 340 MB hard drive, Tseng SVGA video. No sound card, no CD-ROM drive. But in the summer of 1994, if I wanted a 486 over 50 MHz for less than $1500, that Compaq was my only option outside of a Packard Bell. I wanted the 66 MHz speed but didn't care much about the math coprocessor because I didn't run any software that would make much, if any use of it. As long as I could run MS Word 6, Tony LaRussa Baseball, Railroad Tycoon, and Civilization and run them fast, I was happy. And that SX2/66 ran all of that at a good clip.
Mine was in a low-profile Presario. Would you believe I paid almost $1300 for that machine in 1994? 486SX2/66, 4 MB of RAM (expandable to 56 MB), 340 MB hard drive, Tseng SVGA video. No sound card, no CD-ROM drive. But in the summer of 1994, if I wanted a 486 over 50 MHz for less than $1500, that Compaq was my only option outside of a Packard Bell. I wanted the 66 MHz speed but didn't care much about the math coprocessor because I didn't run any software that would make much, if any use of it. As long as I could run MS Word 6, Tony LaRussa Baseball, Railroad Tycoon, and Civilization and run them fast, I was happy. And that SX2/66 ran all of that at a good clip.
I have a "486" no name mb with a TI486 SLC at 33mhz . As it boots it reports a 386 , on the bios it has a sticker that says its a 386. LOL
It also hase a socket to add a 387 co-cpu.
If id have bought that new I would have been REALLY pissed that my "486" was reporting itself as a 386 . LOL
The mb seems to be really well made . Its very small only half the size of a AT board. 6 16bit ISA slots. 4 slots for ram.
Its also very compatiable and I use it as my "old test system" as it works equally well with IDE and MFM controllers.
It also hase a socket to add a 387 co-cpu.
If id have bought that new I would have been REALLY pissed that my "486" was reporting itself as a 386 . LOL
The mb seems to be really well made . Its very small only half the size of a AT board. 6 16bit ISA slots. 4 slots for ram.
Its also very compatiable and I use it as my "old test system" as it works equally well with IDE and MFM controllers.
Thats because that chip is basically a 386. I'm not sure on the internal architecture, but externally it is a 386dx chip. I have one in my compaq portable 386, or something close as I can't recall, and it runs noticably faster. If I recall it even had internal cache that if you ran the included software would give an additinal boost.