Geforce 820m slower than intel integrated graphics (bay trail)

[domovoi]

It's really quite bizarre. When I force PPSSPP to use integrated graphics, I get pretty good, though not perfect, performance for a game like Tactics Ogre (usually 100%, but the occasional framerate drop). But when I force it to use the 820m, performance drops significantly to around 40-60%.

Using MSI Afterburner, I can actually see that the GPU load for the 820m is 100% when I tell PPSSPP to use the 820m, and 0% when I tell PPSSPP to use integrated graphics, which is what I expect. It might be a driver thing (though I've tried both the ASUS-provided driver and the most up-to-date Nvidia driver using a modified INF file), because I also see a performance discrepancy using Dolphin (though to a much lesser extent). But when I run 3DMark11, the 820m's score is significantly higher than the Intel HD Graphics score (about double).

I've also turned off all throttling, and ThrottleStop shows that none of the CPU cores are being throttled. I've also set the 820m to use highest performance possible.

Anyone else seeing something similar?

Machine specs:
ASUS EeeBox EB1037
Intel Celeron J1900
Nvidia Geforce GT 820m
4 GB RAM

[solarmystic]

Have you verified that the 820m is reaching performance clocks when you're running PPSSPP?

I know you've already tried using MSI Afterburner to monitor the actual GPU usage whilst running the emulator, but what does it say about the actual clocks of the GPU? (Alternatively, you can try using GPUz to monitor the clocks and usage in real time too.)

According to notebookcheck.net, the peak clocks for the 820M in performance mode are as follows:-

Core Speed 775 MHz
Shader Speed 1550 MHz
Memory Speed 1800 MHz

There is no way that the Intel HD Graphics (Bay Trail) (which is basicallly a cutdown version of the Intel HD 4000 graphics chipset) should be surpassing the 820M in performance mode, which should be easily getting 100% speed in Tactics Ogre all the time with the default settings (2x Rendering Resolution). In fact, the performance of the 820M should rival that of the Intel Iris Graphics 5100 chipset.

[[Unknown]]

Does the performance change if you use crazy high settings?

For example, Render Resolution = 8x or higher. Does the fps get even worse on the NVIDIA card, or does it continue to be about the same? If it's still the same, there's something else mucking with it, I think.

-[Unknown]

[Alexia2233]

Try GT640M. It works great and you will get fast speed. Promise. :-)