AsRock P4i65G polycap/polymod advice?

[Erroneous Hyphen]

Hello!

I have a Pentium 4 motherboard, a AsRock P4i65G that I'm wondering whether it would be worthwhile doing a polycap upgrade on? The existing capacitors look fine to me, none are bulging or leaking that I've noticed. I was approaching it more from an 'upgrade' perspective, as to whether there would be any benefit to do such a mod even if the existing capacitors look fine?

I believe that if I do go down this route, for the Voltage Regulation circuits that I should be sticking to the same capacitance and voltage, and that a higher ripple voltage and lower ESR can be beneficial?

for the other parts of the board however, I've heard mixed advice - some saying to halve capacitance but keep the same voltage (this seems like a dangerous plan to me that may impact stability), some saying to follow the same rules as with the Voltage Regulation circuits, and some saying that I would need to match the ripple voltage and ESR specs as well or risk blowing the board.

Ive attached some photos of the board and caps for reference - any advice would be greatly appreciated.

Thanks,

-Erroneous

[SwedishDiesel]

Re: AsRock P4i65G polycap/polymod advice?

I've asked similar questions in the past regarding capacitance and ESR with poly caps, see here: https://www.badcaps.net/forum/showpo...11&postcount=2

As far as I know high ripple and lower ESR are ideal for motherboards.

It is an older board so I suppose you could replace the caps for peace of mind, but if they look fine you might as well leave them.

[stj]

Re: AsRock P4i65G polycap/polymod advice?

if it works - it works
if it gets unstable then replace the ones around the cpu with either 1000uf 6.3v or 1500uf 6.3v
no point being clever and trying to under-rate the voltage or capacitance these days - poly's cover those values just fine.

[ChaosLegionnaire]

Re: AsRock P4i65G polycap/polymod advice?

it depends on the age and quality of the caps and whether they are japanese or not. i know asrock likes to use junk caps on their boards and the board u have is from the bad cap plague era.

and after loggin in and viewing pics of your board, it appears u have a boardful of ost caps, save for the caps at the cpu vrm input near the atx 12v connector which are sanyo jap caps. ost caps are regarded as junk caps around here. check the bad cap list thread. if they dont fail now, they will sometime in the future. if your intention is to make that retro hardware last as long as possible for some niche use u have for them, then i strongly recommend a replacement. it also depends if u are using a cooler northwood or the hotter prescott on the board.

also what series of green sanyo caps do u have around the cpu vrm input at the atx 12v connector? if they are sanyo wg caps, they should be okay. if its wx, those series are failure prone and need replacement also.

for the other parts of the board however, I've heard mixed advice - some saying to halve capacitance but keep the same voltage (this seems like a dangerous plan to me that may impact stability), some saying to follow the same rules as with the Voltage Regulation circuits, and some saying that I would need to match the ripple voltage and ESR specs as well or risk blowing the board.

the advice varies because of all the differing cpu vrm designs on various motherboards. thats why u post the model of the board so we can study pics of the board's cpu vrm design from google images or just upload photos of the board on here.

from the pics of the board, u have a 2 phase cpu vrm and the two C-shaped coils by the set of 3 mosfets have like 5-6 turns which indicates a slower switching frequency, so the two features of the cpu vrm design i mentioned above, prefers higher capacitance over lower esr. u also only have a max of 6 cap spots for the cpu vrm output and those are 8mm diameter caps so u cant use the larger 10mm caps with bigger capacitance and lower esr on there. so in other words, dont lower the capacitance on the caps around the cpu vrm since u only have 2 phases and 6 output cap spots. it has a high chance of making the board and cpu unstable if u do that. excessively low esr can also make the cpu vrm unstable.

so a good recommendation is to just replace all with panasonic fr series. its a very low esr series with up to 10k hour lifetime which will work fine and fit fine on that board.

[Erroneous Hyphen]

Re: AsRock P4i65G polycap/polymod advice?

Ah awesome thanks for the info It's a Prescott CPU its running, although it is overclocked currently also (3.0Ghz OC to 3.3 at the moment)

I'll have to pull it back out and look at the sanyo caps to see. so replace these with Panasonic FRs?

and where you're referring to the capacitors for the CPU VRM, that s where the 5 OST caps are and the blank spot yes? Should I fill that 6th spot?