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BGA GPU switch could need some help

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I bought a Dell m3800 on the cheap and want to beef it up a bit, by exploiting the haswell microcode glitch and swapping the on board gpu.


The Dell m3800 has a quadro k1100m, chip says n15p-q1-a2. I switched it with one from a gtx765m (double the shaders same 128bit memory interface), the chip is named N14E-GE-A1.




I think the soldering went well, I masked everything around the chip with a few layers of tinfoil as heatshield and used a heat gun to preheat it slowly and increased the heat later on. All solder balls were melted and I could pull the old chip clean off. After that I cleaned the joints with desolder strips, Flux and a big solderingiron.





When soldering the new chip in the same way it dropped in one corner first and the rest came a moment later :/ but I still think it should make contact everywhere.


So to my problem, the gpu is not being detected in gpu-z at all. It only shows up in the device manager under other devices as "3d video controller" with error code 28 windows couldn't find any drivers. Nvidia drivers need to be inf modded because the hwid isn't found anywhere. Not even in the drivers that came with it from Dell. When trying to install them it fails at some point and after that the device manager shows the gpu as "unknown device" :c




Anyhow I think it ran with the open-source nouveau driver in Linux, after that I installed the proprietary one and now the install is broken. Have to try this again today.


I know there are people here who did some gpu swaps and have a bit more knowledge than me. Problems could be: bad soldering, vbios incompatibility (wanted to pull it before the swap, was locked down), wrong resistor value for the gpu (I think the hwid changed with the gpu swap, but it should only be related to the one resistors some folks mentioned in another thread)


Have to try it again with the nouveau driver to strike the first error reason from the list, or confirm it I guess...

So i've read the other thread again about  bga gpu swaping, found here

Seems like the ID Resistor is only responsible for the for the last two digits of the HWID, if you take a look at the HWID database here  https://vendev.org/pci/ven_10de&dev/  all the GTX 7XXm start with 11XX and the quadro k1100m ends with XXF6. Seems like i have half GTX765m and half quadro in my HWID. So i'll probably have to find my ID Resistor and change it with something from a Graphicscard with the right GPU.




Got the driver installed with inf mod to a gtx 760m but gpu-z is still not recognizing it. Also nouveau in Linux is complaining that no usable (v)bios was found. The vbios is inside the normal bios on this model. I tried simply inserting a acer 760m bios and flashed it. It'll still boot etc but everything is still the same

Edited by Nero243
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It looks to me like your gk106 may have popcorned. It looks like the chip packaging is bulging in the lower right corner at the diagonal capacitor in the last image you linked. Did you prebake the chip at all to remove moisture?


If it's not popcorned then you should try to match the hardware ID in vBIOS to what the card now calls itself. I found in optimus mode that you can have them mismatched on maxwell class GPU, but not if the card is the primary GPU. Have you tried the dGPU as primary? If you haven't yet, trying it may give you a blank screen with no way to get the iGPU back to primary without a BIOS flash via programmer. A blind normal flash or cmos battery removal often does not reset all bios settings.

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First of all thanks for your fast answer!

Flashed a new Bios with a modded vBios from a xps 9530 (GT750m), disabled the IGFX and set it to PCie. Still boots up with the IGPU and the Device id of the Nvidia GPU changes again with subsys all zero. And yes it wobbled a bit up on the corner, i only preheated it for like 2mins with the heatgun before cranking up the heat to melt the solder. Used the same Temps i had when unsoldering and the old chip and it still looks fine.

So i guess i popcorned it, wasn't expensive but still annoying. Was my first try on BGA, i only did lots of SMD soldering before.

But you think a BGA swap with a onboard GPU should be possible? Then i'm going to search for a new chip and try it again.

How long should i preheat a chip, before soldering, and at what temperatures?

Also does the vBios Checksum matter? I can flash everything with afudos /gan or with my CH341a so nothing is being checked.

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I think my BIOS Mod finally worked, the vBios is 2 times in the normal AMI Bios once as Option ROM and another time seperatly. The DEV ID is once in the Option Rom section right before the vBios and in both vBios's. I changed it there and changed it in both vBios's with adjusting the checksum over kepler bios tweaker. Now the GPU comes up as "Microsoft Basic Display Adapter", for some reason the DEV ID in Windows changed to 11D7 (its still 11F6 is the modded vBios's) and has the Error Code 31 "The Driver trying to start is not the same as the Driver for the POSTed Display Adapter". I think i'll change the vbios again to 11D7 and look whats going to happen.

I still think the Chip is dead but at least i guess i'm getting somewhere in terms of Bios modding c:

The changing DEV ID depends on the selected bios PCIe and IGPU settings, i hope this is just because the chip is dead or the whole resistor id thingy wouldn't apply to onboard GPUs.

Edited by Nero243
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