XFX 9500GT 1GB volt mod [56k WARNING] - Overclock.net

crashdummy35 · 10-13-09

CL3P20 has been really cool about helping me along as I try to volt mod my old XFX 9500GT 1GB..

It was after seeing a 9400GT running 1040 on the core that I decided to attempt a vmod and see what my 9500GT could do.

My XFX has been pretty good being able to run up to 800 core, 1850 shader and 576 mem completely stable. For the most part it ran at 780/1850/576, idling at 42/44c and peaking at 55/60c under load with the flimsy stock cooling solution.

I've ordered a budget (cheap really) after market cooler from Tiger as I can't justify spending huge amounts of loot on this little experiment, i.e. water. Ultra Performance VGA Cooler. ***Update here. The cooler did not fit my card. But, I made it fit. Even though it's a bit offset and crooked, it lowered my temps at idle by almost 10c and lowered my temps under load (1 hour of COD4) by about 12c. For a grand total of 26 bucks it was worth it.***

I'm totally new to vmods and I haven't been able to find one for this model of 9500GT anywhere. So, I decided to create this thread and share the experience of completing my first vmod (or creating my first brick) with anyone wanting to have a peak at how it's going. It'll also allow CL3P20 to keep from having to answer so many PMs from this vmod noob

.

Before you begin, take a moment to watch these two videos please. They make the soldering process a bit easier:

Quote:

Tinning a soldering iron: http://www.youtube.com/watch?v=ZBiUjfUxXjU

Quote:

Tinning the wire: http://www.youtube.com/watch?v=bK_bn9xkqbo If you tin the wire correctly, you will only have to hold the wire up against the point you want to solder it to and then touch it gently with the hot soldering iron. The iron will melt the thin coating of solder on the wire and adhere it to the point. Try not to leave a huge bulb of solder on the wire after it's tinned--it makes a mess.

XFX 9500GT 1GB vmem mod:

So, I finally got the first part of the mod done and it ended up being different than I had first anticipated. Here is the final diagram and relevant photos:
U501 on the back of the pcb:

Stock Resistance in ohms from pin #4 to ground ~556:

These caps immediately below the coil can be used to measure voltage for the vmem; use the solder points on the back of the pcb ~1.79v stock (black DMM probe to your case's metal or a screw on it and the red probe to one of the points on the back of the caps, be sure your DMM is set to voltage DC, mine says DCV on it):

Soldered and super glued VR--be sure and tune it before hand to the full Res!!!:

Pin #4 on U501 taped off, tuck the tape in very carefully around surrounding components/pins to avoid seepage--I used a magnifying glass to check my solder after. I kind of soldered it a bit up on the pin, near the top of the chip. Please be very very careful here:

The soldered pin #4 It should really be noted that even with the 20k VR tuned to the max Resistance before it was soldered into the circuit, my vmem voltage went up...and not in a tiny way either; I went from the stock 1.79v to 1.85v idle. When you boot (after thoroughly checking your work beforehand) be ready to quickly read the vmem voltage and power down if you have to:

No benchies yet. I'm slowly studying temps and voltage variations.

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Before you do anything like this, if you are new to vmodding, like I am, please take the time to click on the link in CL3P20's sig and read through the guide very carefully a few times. The information there is invaluable! It really helped me.

I will be updating this thread when I get the vgpu mod figured out. The results will probably be posted on page2 to keep the 56k down to a bare "annoying."

I hope this can help someone out.

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VGPU VOLT MOD

Here's the diagram, on this card U503 is the vgpu controller:

U503 stock Resistance:

Stacked 50k Vrs:

Outter VR pin to Ground:

Center VR pin to pin #4:

It's important to tune the VRs to max resistance; even at max resistance, once wired into the cicuit they lowered the resistance right off to ~ -120 ohms giving me 1.28v. Cooling is super important here. With the 20 dollar aftermarket cooler I rigged onto this card I'm still only idling at 39c with 1.28v right now.
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And a special thanks to CL3P20 for really taking the time to help me through this first part of my little mod. I'd Rep you 100 times if I could bro.

crashdummy35 · 10-13-09

Edited.

**CL3P20** · 10-13-09

as in the PM..use an external ground point, and measure the resistance @ pin4.

*Also confirm continuity between the legs and the closest adjacent resistor..if they are connected and resistance looks good, we can start with a pencil mod to monitor the changes/effects before soldering.

crashdummy35 · 10-13-09

Edited correctly I hope.

**CL3P20** · 10-13-09

Well, they have the same R values..they are more than likely directly connected.. lets start by noting the stock GPUv...then removing the GPU, to pencil the marked resistor near the U501. Measure the R value after penciled...you will only want to lower the R value by ~5-10ohms for starters. Then insert the GPU, and measure for new GPUv.

el gappo · 10-13-09

is that the same pcb layout? i cant tell from your pic http://benchtec.co.uk/forums/showthread.php?t=3649

crashdummy35 · 10-13-09

Quote:

Originally Posted by el gappo

is that the same pcb layout? i cant tell from your pic http://benchtec.co.uk/forums/showthread.php?t=3649

It's a bit different. The newegg 9500GT link has the picts of the back, you can use the zoom tool on them.

crashdummy35 · 10-13-09

Quote:

Originally Posted by CL3P20

Well, they have the same R values..they are more than likely directly connected.. lets start by noting the stock GPUv...then removing the GPU, to pencil the marked resistor near the U501. Measure the R value after penciled...you will only want to lower the R value by ~5-10ohms for starters. Then insert the GPU, and measure for new GPUv.

Okay, here comes more noobness.

#1 How do I measure my stock GPUv--while it's in my rig? Do I use the DMM? <--I ask this one cause I have a mid-tower and my Vendetta is all in the way.

#2 What type of pencil do I use to pencil the resistor? I think I read it has to be a #6? (If so I have to go buy one.

#3 Do I just pencil over the whole thing? (Like a couple of strokes?)

I think I'm seeing the picture now bro. I'm just a little slow on this and these questions would clear everything up I'm sure.

**CL3P20** · 10-13-09

np ...patience is good when modding hardware. Haste leads to 'fireworks and lightning'

#1- With the GPU in the rig and powered, you will need to measure voltage at backside of either: the capacitors close to the mod area, or the mosfets. Measure voltage only with the 'red' probe ..keeping the 'black' probe to an external ground point, not on the GPU.

#2- Most any pencil is fine..I have used mechanical pencils as well....#2pencil works fine.

#3- You want to 'shade' the resistor..literally, make it "darker". Use 5-10x good strokes, from end-to-end, blow away the residual and measure your "new" resistance value with DMM. **You MUST, both measure resistance and shade with GPU out of the rig! Failure to do so will result in blowing the resistor.. = bad news bears !

crashdummy35 · 10-13-09

Edited.

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XFX 9500GT 1GB volt mod [56k WARNING]

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