Reply 40 of 52, by Sphere478
frankmonk wrote on 2023-05-10, 19:10:Minutemanqvs wrote on 2023-05-07, 10:49:
I m'not sure to understand what this jumper does, by default it's on 1-3,2-4 on both of my GA-5AX boards. Of course I don't know […]shevalier wrote on 2023-05-07, 09:27:
According to the manual, this is +3.3V system power.
In general, everything was powered from it in those days, starting from the memory and the chipset.
Again, no one is forcing you to use it.There is a jp11 jumper for that.
I m'not sure to understand what this jumper does, by default it's on 1-3,2-4 on both of my GA-5AX boards. Of course I don't know what previous owner did...
Does it mean that:
1-2,3-4 = use the 3.3V directly from the PSU
1-3,2-4 = convert 3.3V on the mainboard
Why would that be on 1-3,2-4 by default? Because some power supplies couldn't provide enough current on 3.3V? To have a more stable 3.3V than relying on what is provided by a crappy power supply?
Oh and I also see there is another jumper dealing with 3.3V, to basically over-volt it. Previous PCB versions of the GA-5AX don't have this jumper.
That's actually a good question. I'm also not sure which jumper setting would be optimal. I left it on default as well.
The one with least voltage drop and least noise is best.
A modern PSU (with) adjustable rails adjusted at the card might be best. Modern systems rely heavily on 3.3v so they probably will have a nice power quality. Though the distance difference between that regulator and the psu might make it all for naught with wire resistance allowing for less noise control at card.
Long story short, get an oscillascope on the card and test to find out.
Long story longer, it probably won’t matter unless you are overclocking the card. But that regulator might not like some cards and get really hot. So safest is probably to let the modern psu do it. So sorry, there are pros and cons. If you really want to know you need to investigate with meters and tools and analyze.