Empty Cap Spots

[StevieC]

Which ones can have extra caps installed on them to make a board more stable or work for a longer time?

[mockingbird]

Re: Empty Cap Spots

This has been asked before here and the general consensus is not to add any capacitors and the markings are there only for saving money at the fab.

Now power supplies OTOH, from what I understand, you can add components in designated areas, because sometimes the manufacturers skimp.

[PCBONEZ]

Re: Empty Cap Spots

If the position is not in parallel with other caps then it probably won't do anything at all because it is most likely there for an option [or future option, or other model option] that your board doesn't have the other parts for.

If it is in parallel then it was probably put there in the early design phase and left [vice removed] either to allow more options at part procurement time [aka option to use more but cheaper caps] or because testing after prototypes were built showed it wasn't needed [and it costs more to redesign the PCB than to just leave the cap out].

If you are using good quality caps there is no reason to fill the blank spots.
About the only time it -might- help is for extreme over-clocking.
If you aren't doing that then adding caps isn't likely to do a thing for you.

BTW:
Adding uF won't do much for stability in the sense I think you meant.
- It's lowering the ESR that helps that.
Bulk capacitance [uF] helps with 'relatively' slow transients like changing CPU load.
Lower ESR removes more noise and noise is behind most performance/stability type problems.
.

[StevieC]

Re: Empty Cap Spots

Fair enough. I'm not an _extreme_ overclocker BUT! the board is a Gigabyte GA7N400Pro2, and my CPU is an AMD Athlon XP 3200+ which clocks in at a stock 2.2 GHz. I'm considering bumping the multiplier from 11x to 12x to boost the clock-speed to 2.4 MHz and had heard that sometimes if the empty spots ARE in parallel, putting caps there can assist in reaching modestly higher clock-speeds while reducing the need to turn up V-core. Is this true? Also, one of the cap locations fouls my heat-sink. If there is an empty spot that's parallel with it which is clear of my heat-sink, could I put the replacement cap there and leave the original spot empty?

[PCBONEZ]

Re: Empty Cap Spots

If the caps are in parallel then adding one probably won't hurt and might help.
Reports of getting higher overclock by simply replacing crap caps with good ones is pretty common. That happens because the lower ESR reduces noise giving 'cleaner' DC power. Adding a cap of the same grade will do the same thing. So will using the same number of caps with a lower ESR than the originals.

On moving one it depends on the layout.
- If the paralleled cap positions you are changing are all in a group then it should be no problem.
- If they are scattered then it's hard to say because they may be scattered to keep things even on long trace runs. [Long on a motherboard can be 1.5" or less.] The tiny resistance of trace runs allows for a tiny voltage drop from one end to the other which can allow noise [tiny voltages] to exist at one end but not the other. So, if you end up with all the caps on one end of a run then you may get some noise at the other end.

Found a photo of your board and it's an odd layout with what looks to be scattered groups of cap positions for Vcore.
Obviously I can't tell what positions are actually in parallel in a photo so I can only give the concerns and not a solid answer.
.

[ratdude747]

Re: Empty Cap Spots

use a multimeter to check continuity between points?

[PCBONEZ]

Re: Empty Cap Spots

Yes, but it doesn't work with photographs.. hahahaha