When I got my laptop, we decided on getting a fairly decent graphics card for it's time. I have an NVIDIA GT 430M card on my laptop, yet MC refuses to stop using the Intel 4000 integrated graphics on my laptop.
The reason this is in modified client support is because this is on a modified client. I am running optifine, installed from the download linked by the forum page.
What I have tried:
Going into NVIDIA control panel and assigning launcher to processor
Disabling my integrated graphics card (led to black screen)
Going into MC, finding the javaw used for the game, and assigning the NVIDIA processor to that executable (I have no idea why this one refused to work)
Right-clicking minecraft.exe and running with NVIDIA card (similar to 1)
Adding both javaw.exe's (32 and 64) to NVIDIA
What I will not do.
Go into BIOS and screw around with graphics
Try second one above again
I can post a screenshot of the f3 screen showing that it is indeed using the intel integrated graphics card if needed, or post a log of an f3 + c force crash if needed.
I've seen someone go from 15 to 80 fps on a PC with similar specs on an older version of MC when it did work for them, and I believe I could benefit fps wise from this.
JDK will install its own JRE (OS arc depending, X64/X86) (can be opted out of during installation of JDK) which is independent of normal JRE installs. So you can have two 64 bit JREs installed (even if same version) and 1 32 bit.
For say, if I open FTB launcher and go to Advanced Options and on the Java dropdown box, I have 2 Java 1.8 u25 64 bits and 1 32 bit. This is because JDK 1.8 is installed and I did not opt out of the JRE it installs.
I just looked. In the JDK folder there is a folder called jre and it does indeed contain another javaw.exe file. However, I can confirm that this is not the javaw that mc is using. Where are you going with this, could there be a conflict between the two x64 jre's?
I completely uninstalled the JDK, including removing it from the user path. Here is a screenshot showing the JREs multimc finds post-uninstallation.
I also found 2 ways to prove that it is using the java executable under C:\Program Files\Java\jre1.8.0_25\bin\javaw.exe. Both through being the java executable path in MC's profile settings, and the java that minecraft is clearly running when you look at MCs process in task manager. Regardless, I added both the java x64 and java x32 to the NVIDIA profile. Still running on the intel 4000 integrated graphics card.
My laptop is never off of high performance. It's always plugged in, so there's no reason to do otherwise. I did some more research, and it could be because users don't have permission to access the nvidia profile, or I may just have to go into BIOS. I don't think my nvidia card is running at all.