Jump to content
bcunje

Lenovo y410p 1.07 GT750m successfully SLI'ed with a GT755m Ultrabay NATIVELY

Recommended Posts

Hello techinferno, my name is bcunje. I have been an observer of this forum for a while along with notebookreview, however I think this forum better suits my needs.

Summary: I own an early version August 2013 y410p with 1.07 BIOS and single GT750M. I wanted a 750m Ultrabay for SLI, but Lenovo never delivered. So, I bought a GT755M ultrabay when it was on sale for $99 dollars (instead of the now over 200 dollar price), and made it work without ANY BIOS modifications. The laptop is natively supporting SLI without any driver or BIOS modifications. Here's how I did it.

Requirements: -GPUs need the same device IDs 10DE 0FE4 (subsystem ID does not seem to matter, but mine is 380017AA whereas I THINK the y510p's are 380117AA) -It needs to actually fit in the laptop

-vBIOS should be the same, mostly just for clock speeds. The card pulls device ID off of the hardware straps.

The First Step.... I tried just flashing the 750M vBIOS onto the 755M to see if I could get past the BIOS whitelist. That did not work. I used a Raspberry PI to SPI flash the Lenovo provided 750m vBIOS for Windows 8.1. Here's some pics for fun:

SPI Flashing 750M vBIOS onto a 755M card with a Raspberry PI

The Second Step.... User EmberV from notebookreview was extremely helpful in this part. I posted PCB pictures of the GT755M Ultrabay, and he pointed out that although the GT750M and GT755M were the same chip, same RAM, even the same PCB... there was ONE resistor that was configured differently.

GT755M Ultrabay PCB Pictures

Pictured below are the hardware straps. GT755M Left, GT750M Right [FONT=HelveticaNeue-Light] GT755M Resistor Pattern[/FONT] [FONT=HelveticaNeue-Light]10110010[/FONT] [FONT=HelveticaNeue-Light]01001101[/FONT]

[FONT=HelveticaNeue-Light]GT750M[/FONT][FONT=HelveticaNeue-Light] Resistor Pattern[/FONT] [FONT=HelveticaNeue-Light]10111010[/FONT] [FONT=HelveticaNeue-Light]01000101 [/FONT] First thought is that they were just 0 ohm resistors configuring the Device ID, however they are actually resistors, in increments of 5k Ohms, between 5K and 45K which set the Device ID.

More on how Nvidia does hardware straps here: [MOVED] Hacking NVidia Cards into their Professional Counterparts - Page 1

One of my buddies has a y510p GT750M SLI laptop and he was kind enough to allow me to take his Ultrabay apart and poke it with a DMM. This is what I found, with the upper left most resistor being pad 1 and the bottom right most resistor being pad 16.

Pad (GT755M) Resistor Impedance Pad (GT750M) Resistor Impedance
1 1 25k 1 1 34.6k CHANGE TO 35K
2 0 105.7k 2 0 105k
3 1 44.8k 3 1 45.2k
4 1 4.9k 4 1 4.9k
5 0 90.1k 5 1 24.9k CHANGE TO 25K
6 0 85.3k 6 0 84k
7 1 4.9k 7 1 4.9k
8 0 75.4k 8 0 75k
9 0 81k 9 0 93k
10 1 45.4k 10 1 45.1k
11 0 106.9k 11 0 127k
12 0 63.0k 12 0 60k
13 1 29.9k 13 0 80k REMOVE
14 1 25.0k 14 1 24.7k
15 0 60.8k 15 0 64k
16 1 14.9k 16 1 15k


Previously, the y410p would tell you that the Ultrabay is unsuitable for the laptop and tell you to remove it so you couldn't even boot into Windows. Making these changes allowed my y410p to get past the BIOS and into Windows. Simply re-flashing the chip again got it working properly. and the next time I booted my machine I was greeted with this:



Now I'm pushing >200FPS in CS:GO, BF4 on Ultra, Tomb Raider on All high (except stupid TRESSFX)... It's great, except now the CPU is throttling hardcore.

If you have any questions about how I did this please let me know. I'm trying to get my first 5 posts so I can actually be an active member so I can download svl7's y410p BIOS mod to undervolt my CPU and prevent throttling issues while gaming ^_^.

If you are so inclined, you can follow my incremental progress on this thread, although it veers off topic a bit: Y410p [SLI] Purchase - Page 8

tl;dr: 1) modify hardware straps 2) reflash 3) happiness
  • Thumbs Up 3

Share this post


Link to post
Share on other sites

Hi! I have quoted you in a different topic but I use this one as well if you dont mind! I do have an y510p with a single 750m and planning on buying a 755m. Could you help me what and how to modify to make the sli happen?

Thank you very much!

O

Share this post


Link to post
Share on other sites

@oli129 sure thing. There are some detailed instructions on this thread as well as the thread on notebookreview.com. It should be linked above. If you have any questions specifically, let me know. I think the guide should have pretty much all the information you need.

Share this post


Link to post
Share on other sites

hi bcunje..

i already success with your hardware mod..

but still stuck with the flashing vbios..

which method did u use to reflash the vbios?

because the nvflash still got me EEPROM ID: unknown

Share this post


Link to post
Share on other sites

Gz bcunje, it's nice to see you've joined us in the glorious world of y410p SLI'ed =) against throttling, how about Ideafan?

Share this post


Link to post
Share on other sites

hi, what bios version are you using? i have a gt750m5 but it is not detected anywhere? my bios version is 1.10 on a y410 btw

Share this post


Link to post
Share on other sites
hi, what bios version are you using? i have a gt750m5 but it is not detected anywhere? my bios version is 1.10 on a y410 btw

The vbios from the Lenovo website should work. It will not be detected unless any vbios for it is installed. I bought the ultrabay from ebay and it wasn't detected until I installed the bios. I believe any version will get it running.

Share this post


Link to post
Share on other sites
The vbios from the Lenovo website should work. It will not be detected unless any vbios for it is installed. I bought the ultrabay from ebay and it wasn't detected until I installed the bios. I believe any version will get it running.

I got a GT750M5 and I can not even get into windows because of the "Unauthorized slave vga card is plugged in. power off and remove it" message. I am using the 3.08 BIOS version. Is there any way to baypass this message?

Share this post


Link to post
Share on other sites
I got a GT750M5 and I can not even get into windows because of the "Unauthorized slave vga card is plugged in. power off and remove it" message. I am using the 3.08 BIOS version. Is there any way to baypass this message?

I think there is no solution. I bricked my y410p trying. Lol

Sent from my SM-G920I using Tapatalk

Share this post


Link to post
Share on other sites
I think there is no solution. I bricked my y410p trying. Lol

Sent from my SM-G920I using Tapatalk

Actually there is a solution, my GT750M5 (made for the y510p) is working properly with my y410p using the 3.08 bios version. You have to ensure it fit completely, otherwise you will receive always the "Unauthorized slave vga card is plugged in..." message.

Share this post


Link to post
Share on other sites

Where can I buy the  Ultrabay equipment

 

If I have some problem with the independent graphics GT750, Could I use the Ultrabay as a graphics card instead of SLI ?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.