Overclock.net banner

1 - 20 of 36 Posts

·
Registered
Joined
·
1,989 Posts
Discussion Starter #1
Just bought 30 16v 1500uf low esr caps and I am going to throw them on a 750i ftw and a gts 250 just to get my feet wet. My question is how do I hook them up, I know where jsut not how I have always assumed it was + to + and - to - , recently I saw a picture that looked like they had it running + to - and vice versa so......... which one is it???? And do you guys have any tricks to capping the backside of a board then benching it??? I have a plan but not sure if its the best one. Thanks guys
 

·
Premium Member
Joined
·
4,914 Posts
is this even worth it at above ambient? or would it only be good for a small gain?
 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #5
Just looking for an answer. No its not worth it at ambient, just want to do the mods and test them before I put a pot on the board.
 

·
Retired Benchmark Editor
Joined
·
10,194 Posts
Just piggy back the leg under the board. The pic a couple posts up is how you can place multiple ones in series. I'm not sure if series has lower ESR then parallel or not.
 

·
Bigger is Always Better
Joined
·
1,115 Posts
I believe that it's caps in series, + to -, make the value lower than the value of a single cap. Caps in parallel, + to + and - to -, doubles the value of a single cap.
 

·
Retired Benchmark Editor
Joined
·
10,194 Posts
Quote:


Originally Posted by hollywood406
View Post

I believe that it's caps in series, + to -, make the value lower than the value of a single cap. Caps in parallel, + to + and - to -, doubles the value of a single cap.


So you're saying: series lowers ESR and parallel increases uF?
 

·
Banned
Joined
·
16,364 Posts
Quote:


Originally Posted by PizzaMan
View Post

So you're saying: series lowers ESR and parallel increases uF?

This.

You get 1/2 the original 'uF' in series, but roughly double ESR.. As well, keep in mind, that the OEM PCB layout has its capacitors lined in series as well....so you would be effectively just adding a 3rd or 4th "stage".. [referring to the above pic of the capped 480].

*as for a mobo, you will want to add your caps in series as well to the existing set around the CPU and NB socket/area..rarely on a mobo PCB will you ever see caps in series, as the current demands are not as intense [prolly good idea for high vcore clocking]. Be careful though..adding more caps can just make things that much more difficult to insulate...and failure to contain the extreme cold will result in shorted caps, dead hardware, or just buggy CB issues in general...

 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #11
Is there another way to determine the polarity of the mlcc's without measuring when the card is powered up. By the way just used that shot as a reference the cards I am working on are a 8800gts 320 and a gts 250
 

·
Retired Benchmark Editor
Joined
·
10,194 Posts
The ground side is typically marked by a line down the side or the top is colored.
 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #13
Not the cans, talking about the little multi layer ceramic caps or, mlcc's Cant tell with dmm because both sides have continuity with power source.

Just got done adding caps to my 250 and so far no good results to show. Vcore moves but not much and no extra push in mhz yet. I have noticed this card has an issue with vdroop that might explain the fluctuation.

Hey pizza are you a mod? If so you can move this post to the gpu section and ill edit the title to change it to a 250 post.
 

·
Retired Benchmark Editor
Joined
·
10,194 Posts
I've noticed on my DMM that I typically get a 0.01 from the hot side and -0.00 when reading ohms it from the ground side.

My editor privileges are limited to the benchmark sub-forums. Haven't been able to talk them into V'mod sub-forum privileges yet.
 

·
Banned
Joined
·
16,364 Posts
the '+' side is the one labeled on mlcc's ..with the stripe, the corresponding position on most all PCB's will be marked to match as well
 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #16
Added more caps and card is actually performing worse than before. Or so it seems. I have a few more things to try before I give up. I think I am making vdroop worse but I cant tell because I didnt measure before the mod only after. But vantage gpu score is lower because of fps in caleco which more than likely means not enough power. So I am willing to bet that the extra caps are the cause of this. I am going to try to add more power sometime this week. Vcore control through nvflash is pretty much endless on this card so this should be fun.

Ill ad some pics of my work and ideas tomorrow I hope. Gotta go if im late for work again because I stayed up untill 4 for the millionth night in a row I am a dead man.
 

·
Banned
Joined
·
16,364 Posts
as I understand it:

For GPUv's allowable with air cooling, you will never see the need for more series capacitance on the 480's [exception being the C1045 position]. If you added caps in series..then try them in parallel and compare again.

*the ESR rating of your caps could be 'unusable' or creating some additional noise in the circuit... I dont know for sure, but its definitely a possibility. These being 16v caps, low ESR will cost you some $$.
 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #18
ya the ones I got are low esr, forget the exact measurement though. the capacitance is pretty high though 1500 uf to the usual 470, I am not modding a 480 just used that pic for reference. I am capping my gts 250. Didnt you do one of those cl3p20 I swear I remember reading you doing one of those and getting 875mhz core on air?
 

·
Banned
Joined
·
16,364 Posts
yup..just over 800mhz stable for gaming





..no voltage mods either... all stock *cept for flashed BIOS.. which is why default clocks are higher than stock
 

·
Registered
Joined
·
1,989 Posts
Discussion Starter #20
cool im where I should be then. I stacked caps in the wrong place the first time around. I am passing vantage @ 820/1220 but thats when temp comes into play. I can get 825 to pas if I pull the shaders back but I really dont like toing that. Its good for about 5 extra points in vantage.
 
1 - 20 of 36 Posts
Top