feipoa wrote on 2022-11-14, 10:11:
elbbar, I'm not sure what you are showing a photo of...
On the subject of capacitors and the design of a CPU board, what differences can you spot between the two designs pictured? Which design has stability problems?
Did you watch the videos I posted URLs for? Can you be more specific about which part you don't understand?
feipoa wrote on 2022-11-28, 06:20:
I haven't seen any 386 or 486 interposer use a dedicated cap on each Vcc like that.
Do you know what capacitors look like? There are also differences in what can be made by hand and what can be made by automated processes now (and in 1995). There are also differences in something designed/manufactured to a price point and something for performance/hobbyists. For example, "better" could mean cheaper/easier to make, or it could mean the ability to clock higher.
If you want to talk specifically about 486 chips, here is a picture of a 486-type adapter board. The surface mount CPU chip has capacitors lined up as close as possible/practical to many of the pins (directly beneath). I don't know the pinout for these chips but I have a pretty good guess as to which pins those capacitors are connected to.
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Now if you compare a 486 to some of the newer CPUs, what can you observe about the type, quantity, and locations of capacitors? Is this making sense?
You posted a picture of your hand made socket adapter that has problems with higher frequency operation. Given the time you must have put into it, adding a few (or even a single) bypass capacitor would be trivial. This experiment would be completely reversible. Even accurately using a scope to measure signals like you've described is more work than simply adding a couple capacitors to see what happens.