49 lines
2.5 KiB
Markdown
49 lines
2.5 KiB
Markdown
# 🛠️ CMP 50HX 20GB VRAM Mod & Driver Patching Guide
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This guide covers how to physically mod and software-unlock the **NVIDIA CMP 50HX** from **10 GB to 20 GB VRAM** (20,480 MiB per card), based on the validated research from [`xrip/cmp50hx-unlock`](https://github.com/xrip/cmp50hx-unlock).
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---
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## 1. Hardware Modification: Swapping GDDR6 BGA Chips
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### Architecture & Memory Topology
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* The CMP 50HX is built on the **TU102 PCB** with a **320-bit memory bus (10 memory pads)**.
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* **Stock Configuration**: 10x 1GB (8Gbit) 14Gbps GDDR6 BGA-180 chips (e.g., Samsung `K4Z80325BC-HC14`).
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* **20GB Configuration**: 10x 2GB (16Gbit) 14Gbps/16Gbps GDDR6 BGA-180 chips:
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* **Samsung**: `K4ZAF325BM-HC14` or `K4ZAF325BM-HC16`
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* **Micron**: `D9ZCL` (MT61K512M32KPA-14) / `D9WCW`
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* **Hynix**: `H56G32AO8DX-004`
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### Hardware Strapping Resistors
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* After desoldering the old 8Gbit ICs and soldering the 16Gbit ICs:
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* Locate the **memory density strapping resistor dividers** on the rear of the TU102 PCB near the memory controller.
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* Move the strapping pull-up/pull-down resistor to configure the memory controller for **16Gbit per channel**.
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---
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## 2. The Software Barrier: NVIDIA Booter Error `0x8d`
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### Why Stock NVIDIA Drivers Fail on 20GB CMP 50HX
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* In stock closed drivers, the firmware security module (FWSEC) uses hardcoded WPR2 bounds calculated for a 10GB address space.
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* On a 20GB card, stock FWSEC creates:
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```text
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WPR high:low = 04ffee00:04ffe000
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span = 00000e00
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```
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* Because the hardcoded 10GB bounds do not match the 20GB span, NVIDIA Booter aborts with error `0x8d`, GSP-RM fails initialization, and `nvidia-smi` detects no devices.
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### The Fix: Dynamic WPR2 Handling (`xrip/cmp50hx-unlock`)
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* The patched NVIDIA Open Kernel Module (`610.43.03`) reads the FWSEC WPR2 range dynamically for each GPU's PCI BDF (Bus/Device/Function).
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* It accepts span `0xe00`, saves the low/high bounds per BDF, and passes GSP readiness checks.
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* **Mixed Cards Supported**: You can run 10GB and 20GB CMP 50HX cards in the same system simultaneously because WPR2 bounds are indexed per PCI BDF.
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---
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## 3. Multi-Card VRAM Scaling for LLM Inference
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| Cluster Setup | Total VRAM | Model Capability |
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| :--- | :---: | :--- |
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| **2x 20GB CMP 50HX** | **40 GB VRAM** | Runs `Llama-3.3-70B` or `Qwen2.5-72B` (Q4_K_M) across 2 slots! |
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| **3x 20GB CMP 50HX** | **60 GB VRAM** | Runs `Qwen2.5-72B` (Q6_K / Q8_0) with full 64K+ context |
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| **4x 20GB CMP 50HX** | **80 GB VRAM** | Enterprise A100-class capacity (runs 70B FP8 / Q8_0 at 128K context) |
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