Hi everyone,

I'm testing portable USB-C charging behavior on my **Legion Slim 5 14APH8 (82Y5)** using Lenovo's proprietary **Legion C135 GaN charger plugged directly into the rear USB-C port**, and noticed a very counter-intuitive power allocation between power profiles.

I'd like to check whether retail units behave the exact same way or if this is related to running a retail BIOS on an engineering board.

**Hardware & Firmware Context:**

* **Chassis / Model**: Legion Slim 5 14" (82Y5, OLED)
* **Processor**: AMD Ryzen 5 7640H 
* **GPU & Memory**: RTX 4050 Laptop GPU (6GB), 32GB LPDDR5X
* **Firmware**: Flashed with the **latest official retail BIOS** from Lenovo's support site. Performance / Beast mode works normally (\~100W+ sustained GPU) when plugged into the full AC rectangular adapter.
* **Charger Setup**: Lenovo Legion C135 GaN charger connected directly to the rear Type-C port using the original dual Type-C cable. 

**The Anomaly (FurMark / GPU Stress Test via C135 Type-C):**

1. **Quiet Mode (Fn + Q, Blue LED):**
   * The GPU stably maintains **\~60W – 65W** without severe core clock throttling.
2. **Balanced Mode (Fn + Q, White LED):**
   * The GPU drops and gets heavily throttled down to **\~50W**.

**My Hypothesis:**

In Balanced Mode, the EC firmware seems to allocate/reserve an aggressive \~30W+ power envelope for the CPU to prevent system stutter and avoid drawing power from the battery, which ends up starving the GPU down to \~50W on this input level. In Quiet Mode, because the CPU package power is brutally capped to minimal levels, Dynamic Boost or the EC frees up that headroom and lets the GPU utilize up to 65W.

How ever, I also had an R7000P 2022 and it does support 135W input via Type-C port.

**Questions for the community:**

1. For owners of retail Legion Slim 5 14" (or Slim 7 / R7000P 2022+) who use the Lenovo C135 charger directly via the Type-C port: Do you see this exact same inversion where Quiet Mode gives you a higher sustained GPU wattage (65W) than Balanced Mode (50W)?
2. Is this standard Lenovo EC behavior across 2023+ Legions when connected to a C135 over Type-C, or could it be an artifact of running the latest retail BIOS on an early engineering motherboard?

Thanks for any insights and HWiNFO log comparisons!

Weird GPU power behavior on Legion Slim 5 14