VOGONS


First post, by Chadti99

User metadata
Rank Oldbie
Rank
Oldbie

Beyond your normal bus speed, voltage, and multiplier. What are the other CPU jumpers doing on say a Lucky Star LS486e ?

Reply 1 of 5, by Doornkaat

User metadata
Rank l33t
Rank
l33t

I think they're used to let the chipset know how exactly to handle stuff like caching on the CPU that's installed.

Reply 2 of 5, by Chadti99

User metadata
Rank Oldbie
Rank
Oldbie
Doornkaat wrote on 2020-08-10, 21:17:

I think they're used to let the chipset know how exactly to handle stuff like caching on the CPU that's installed.

Like Write-Back versus Write-Through?

Reply 3 of 5, by dionb

User metadata
Rank l33t++
Rank
l33t++

Yep, WB vs WT, what A20 is doing, multiplier and voltage settings.

It's incredibly frustrating how almost no manuals actually tell you what is going on, even when they have settings for (at the time of writing) not yet available CPUs that turned out to require different settings when actually released. So you need to reverse-engineer it all. Doable if all parts are known-good, but if you don't know for sure motherboard and/or CPU works that can be incredibly frustrating...

Reply 4 of 5, by Doornkaat

User metadata
Rank l33t
Rank
l33t

The whole statement is based off something I think I read in a motherboard manual once. I don't remember it being any more specific than stating that the jumpers are related to caching, sorry.

Reply 5 of 5, by Chadti99

User metadata
Rank Oldbie
Rank
Oldbie
dionb wrote on 2020-08-10, 21:34:

Yep, WB vs WT, what A20 is doing, multiplier and voltage settings.

It's incredibly frustrating how almost no manuals actually tell you what is going on, even when they have settings for (at the time of writing) not yet available CPUs that turned out to require different settings when actually released. So you need to reverse-engineer it all. Doable if all parts are known-good, but if you don't know for sure motherboard and/or CPU works that can be incredibly frustrating...

Yes quite frustrating. It’s interesting to see zero performance gain in Dos Quake between two cpu jumper selections but up to 10fps difference in GLQuake.