8800s OVP Mod ......

[T_M]

Tested again attaching my OVP mod.
While running i grounded it and that cause a 0.04V boost to vGPU while idling.
Then i rebooted and suffered 0.1+V vdrop and the system wouldn't load windows.

[nfm]

Would any of these work?


I would like to try this on a 8800GT*, the OVP mod did not work for me http://www.xtremesystems.org/forums/...&postcount=402

[T_M]

If those caps came off a motherboard then they should no problem.
The coil is no good from what ive been told.

[N1ck R1mer]

If those caps came off a motherboard then they should no problem.
The coil is no good from what ive been told.

http://www.xtremesystems.org/forums/...&postcount=2340

P.S. B.T.W., I've made the Vdroop mod for my GTS:

http://www.xtremesystems.org/forums/...&postcount=239

I would like to try this on a 8800GT*, the OVP mod did not work for me http://www.xtremesystems.org/forums/...&postcount=402

There is one interesting idea, but still not enough time for that:

http://www.xtremesystems.org/forums/...123046&page=10

[nfm]

Great work N1ck R1mer I appreciate all of your help. I will hold off on the coils, the caps come off A P4 mobo so they should be good. I will try to find the resitors you removed from your GTS. I'm still in process of digesting all of the info. I hope shamino will speak up.

Nonetheless this is a great news to me

This would be the spot to solder caps on 8800GT right?


Edit: So I have to remove 3 (or 2 resistors) from my card to disable OCP since it kicks earlier than OVP, and then try lowering the OVP resistor from 5.2K to 4.7K or lower? I have hard time figuring out what resistors I should remove http://www.xtremesystems.org/forums/...5&postcount=65

[N1ck R1mer]

Great work N1ck R1mer I appreciate all of your help. I will hold off on the coils, the caps come off A P4 mobo so they should be good. I will try to find the resitors you removed from your GTS.

There are two of them at GT, connected to the same primarion pins. If you remove them, it could disable Vdroop, but not the OCP. I dont't have the GT card, so I cant't check this out. Is there any Vdroop on GT w/o any mods?

This would be the spot to solder caps on 8800GT right?

Yepp, right.

Edit: So I have to remove 3 (or 2 resistors) from my card to disable OCP since it kicks earlier than OVP, and then try lowering the OVP resistor from 5.2K to 4.7K or lower? I have hard time figuring out what resistors I should remove

No, I don't know for sure how to disable OCP. The idea is to solder parallel resistors (3 for GTS, 2 for GT) to those capacitors located near the resistors that I removed.

The results of lowering OVP resistor (70b) from 5.2 to 4.7 K are:
1. Vgpu decreases (about 0.1 V)
2. OVP should work at higher voltage than with the stock 70b resistors. Practically point 2 is useless with GTS & GT, cause OCP still works earlier than OVP.

[T_M]

Nick, when i tried the OVP mod on my Ultra i thought i'd done it wrong because vGPU was suddenly 0.1V less than before. Are you actually meaning to say that means my mod was successful?

[nfm]

Nick, when i tried the OVP mod on my Ultra i thought i'd done it wrong because vGPU was suddenly 0.1V less than before. Are you actually meaning to say that means my mod was successful?

I noticed same exact thing, 0.1v less (I had to go down from 5.2K to 4.3K to notice the drop, 4.7-4.9K did nothing)
The 8800GT actually overvolts 0.05 to 0.07v at stock.

Edit: I just did the cap mod, so far so good.

[T_M]

8800GTS 512Mb overvolts about the same at stock as well, however the higher you adjust vGPU, the larger the overvoltage under load
So watch out!

[N1ck R1mer]

Nick, when i tried the OVP mod on my Ultra i thought i'd done it wrong because vGPU was suddenly 0.1V less than before. Are you actually meaning to say that means my mod was successful?

Don't know about Ultra, the resistor for OVP has another default resistance value than 70b at GT/GTS. But I'm sure that OVP mod is very useful with GTX.

Edit: I just did the cap mod, so far so good.

Are you sure about polarity? The "minus" (- - -) cap pin should be on the ground. As I see on the pic, it's right, but for sure...
BTW, soldering is pretty acurate

PS Chemicon KZG caps are nice, Low-ESR (1500x6,3 - about 26 MOhm). Not the best, but nice.
http://www.chemi-con.co.jp/pdf/catal...g-e-070821.pdf

[nfm]

I removed the corresponding resistors on my GT to disable the overvoltage. Card still overvolted but guess what Nick? Card does not shot down anymore no matter what voltage. I did some preliminary testing upping card to 1.6v in 3DMark and 1.5v in Crysis. I ran 3DMark06 at 918Mhz and played Crysis at 900Mhz!

Let my need for mhz begin

[Hazaro]

I removed the corresponding resistors on my GT to disable the overvoltage. Card still overvolted but guess what Nick? Card does not shot down anymore no matter what voltage. I did some preliminary testing upping card to 1.6v in 3DMark and 1.5v in Crysis. I ran 3DMark06 at 918Mhz and played Crysis at 900Mhz!

Let my need for mhz begin

Which resistors would that be

[T_M]

NFM, do you mean that your overvoltage value is now your normal volts?

[nfm]

Not exactly, card still overvolts. At 1.50v idle it overvolts close to 1.60v (firefly 3dmark06). Looks like OVP does not exist on 8800GT , once you disable OCP through removal of two resistors, card will never shut down.

These are same resistors (x78 value) nick removed from a gts, and his effect was no more vdroop.

[dinos22]

I removed the corresponding resistors on my GT to disable the overvoltage. Card still overvolted but guess what Nick? Card does not shot down anymore no matter what voltage. I did some preliminary testing upping card to 1.6v in 3DMark and 1.5v in Crysis. I ran 3DMark06 at 918Mhz and played Crysis at 900Mhz!

Let my need for mhz begin

Not exactly, card still overvolts. At 1.50v idle it overvolts close to 1.60v (firefly 3dmark06). Looks like OVP does not exist on 8800GT , once you disable OCP through removal of two resistors, card will never shut down.

These are same resistors (x78 value) nick removed from a gts, and his effect was no more vdroop.

OMG you just figured out the OVP mod

that was easy :

[Timbosan]

N1ck removed the '70B' resistors, you have removed 2 '70X' resistors. Can you tell me what pins of the PX3544 chip that have continuity to the 2 resistors you removed? It looks like the top resistor joined point 1 in my pic and the second side resistor joined either point 2 or 3.

[Hypertek]

Not exactly, card still overvolts. At 1.50v idle it overvolts close to 1.60v (firefly 3dmark06). Looks like OVP does not exist on 8800GT , once you disable OCP through removal of two resistors, card will never shut down.

These are same resistors (x78 value) nick removed from a gts, and his effect was no more vdroop.

so to get this straight im tryin to understand.. you unsoldered those 2 resistors, and now you can basically up the voltage/overclock the gpu to your hearts desires? (of course withen the limits of what the gpu can handle til it craps out)

[N1ck R1mer]

N1ck removed the '70B' resistors, you have removed 2 '70X' resistors.

No, I've replaced ONE 70b (5,22 K) resistor (it connected to Vmax Primarion pin) with the 4,7 K (first with 5,1 K) to get rid of the OVP, but OCP still works. I've tried to disable OCP, so I removed that three '78X' resistors, but the effect was unexpected (I only discovered the Vdroop mod as a result).

I removed the corresponding resistors on my GT to disable the overvoltage. Card still overvolted but guess what Nick? Card does not shot down anymore no matter what voltage. I did some preliminary testing upping card to 1.6v in 3DMark and 1.5v in Crysis. I ran 3DMark06 at 918Mhz and played Crysis at 900Mhz! Let my need for mhz begin

I'm glad to hear that! The resistors you removed definetly belongs to the current control scheme, so my first objective was to disable OCP.

[Timbosan]

right my bad sorry. i was at work, my mind was somewhere else & i got the ocp & ovp mods confused

[nfm]

Is it technically possible to remove overvoltage on my 8800GT? BTW I did not do OVP, it's at original 5.2K. If you guys (Nick, T_M or Timbosan) have any ideas on unsoldering few things let me know

@Timbosan
I do not know how to check the continuity

[Timbosan]

i think the OVP mod would be one of these 2 resistors i identified with the pink square. What are the 2 resistors resistances?

to check continuity you set the dmm to the 'diode' setting, it looks like an arrow with a line through it near the head. alternatively you could set it to resistance and see if there is a zero resistance connection.

[nfm]

I wasn't sure which points, I sticked it to where I unsoldered the resistors, top showed 1.22 and bottom 0.53 (according to the pic)
70B is the OVP for 8800GT, but that adjacent 63B resistor looks interesting .

[N1ck R1mer]

i think the OVP mod would be one of these 2 resistors i identified with the pink square. What are the 2 resistors resistances?

Hey! I'm not gonna repeat what I said once. There is ONLY ONE Vmax Primarion pin.

[Timbosan]

yeah i know the 70b is ovp resistor & connects to vmax pin. we sorted it via PM i thought he meant something else - to remove ovp completely (as he has performed the ocp mod the only limitation is voltage) I thought he wanted to unsolder the resistor - so i wanted to see what it had continuity with to see if that would cause trouble.

[hehee]

i've problem of card shutdown when i do anything over core 710mhz.vmod at 1.45...
is anyway to remove few resistor for GTX to disable OVP...?