Cyrix 386 -> 486 upgrade
Eric Mercer
that it was interesting. However, I am still not sure. I am interested
in hearing from people who have tried this upgrade chip. Horror stories,
regrets, etc. I would also like to hear anything else (opinions, info,
etc.) on the subject of these upgrades from anyone else.
-Eric
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|Eric A. Mercer |
|mer...@ceres.med.upenn.edu CVRC, University of Pennsylvania |
|office: (215)662-7837 |
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Michael P. Caldwell
On 28 Oct 1994, Eric Mercer wrote:
> I was just reading about Cyrix's 386->486 upgrade, and I was thinking
> that it was interesting. However, I am still not sure. I am interested
> in hearing from people who have tried this upgrade chip. Horror stories,
> regrets, etc. I would also like to hear anything else (opinions, info,
> etc.) on the subject of these upgrades from anyone else.
Well, I upgraded my 386DX to a 486DLC almost a year ago, and I've
never had a problem. You must keep in mind, that the only reason a
real 486 won't work on a 386 motherboard is that it was redesigned to
incorporate a coprocessor. If you want to compare it to a 386, the
only differences is that it's almost twice as fast (the clock doubling
one is even faster). If you want to compare it to a 486SX, there are
only a few slight differences (mostly cache related):
1) Most 386 motherboards don't have the hardware to support the
internal caching used by 486 processors (some have been redesigned to
support it). So what the DLC does, is it uses bus arbitration to
determine when the internal cache might be invalid. Because of this
method it will sometimes flush the cache unnecessarily, but this is the
best you can do without the additional hardware support (and better
safe than wrong).
2) With an SX or DX you simply turn the internal cache on in the CMOS.
With the DLC, it takes special software (at least it's not a TSR or
driver) and some tweaking to get the best performance, which varies
from computer to computer.
#'s 1 & 2 are not an issue for those motherboards that do support
internal caching.
3) It has only a 1k cache, as opposed to Intel's which has 8k, or
IBM's which has 16k. There is a noticeable performance difference
here, but it has to fit in a normal 386's space.
4) Because it performs some instructions faster than Intel's, most
software will incorrectly determine its speed. e.g. I have a 40mHz
486DLC with a 40mHz 387DX, but most programs (such as Norton's
SysInfo) think I have an 45mHz 486DX. This has never been an actual
problem for though.
To summerize, it's better than a 386, and cheaper than replacing
your whole motherboard. Well at least it was when I got it. My DLC
chip cost about $50 last year, less than $40 after trading in my 386.
However, the last time I checked the DLC was going for $90, and the
DX^2 was going for well over $200. If you're willing to pay over $200
for an upgrade, you may want to just go ahead and buy a new 486SX &
motherboard.
.Mike
g. cheng
Eric Mercer <mer...@ceres.med.upenn.edu> wrote:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>I was just reading about Cyrix's 386->486 upgrade, and I was thinking
>that it was interesting. However, I am still not sure. I am interested
>in hearing from people who have tried this upgrade chip. Horror stories,
>regrets, etc. I would also like to hear anything else (opinions, info,
>etc.) on the subject of these upgrades from anyone else.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Eric, read the latest issue of Windoze. An upgrade of merely the
processor will never yield the same results as a full upgrade (CPU and
Motherboard). If you have a 386 make sure that you can bring over the
RAM and get a new motherboard and CPU.
You will be spending way too much for marginal gains with just a CPU
upgrade. A 486 DX-2 VESA standard motherboard is dirt cheap these days.
Do yourself a favour and get a new 486 VESA standard motherboard and a
DX-2 66 CPU, you will thank yourself later!
Hope this helps
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"Aerodynamics are for people who cannot build engines" --- Enzo Ferrari
Godfrey Cheng ---- r...@julian.uwo.ca
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