A key factor influencing Graphics Performance Unit (GPU) is memory bandwidth. It determines how quickly data can move between the GPU and its memory.
This calculator helps users estimate and optimize the bandwidth of their GPUs, ensuring they achieve peak performance for their workloads.
To use the calculator enter:
- Memory Clock Speed
- Memory Bus Width
What is GPU Memory Bandwidth?
GPU memory bandwidth refers to the rate at which data can be read from or written to the GPU’s memory, typically measured in gigabytes per second (GB/s). It’s a critical metric for tasks that require high data throughput, such as:
- Rendering high-resolution graphics.
- Running complex simulations.
- Training machine learning models.
Formula for Calculating GPU Bandwidth
Memory Bandwidth (GB/s) = Memory Clock Speed (GHz) × Memory Bus Width (bits) × 2 ÷ 8
Where:
- Memory Clock Speed: The effective speed of the memory, often provided as a double data rate (DDR) value.
- Memory Bus Width: The width of the memory interface, in bits (e.g., 256-bit, 384-bit).
- The factor of 2 accounts for DDR memory, which transfers data twice per clock cycle.
- Dividing by 8 converts bits to bytes.
Example Calculation
Scenario: A GPU has the following specifications:
- Memory Clock Speed: 1750 MHz (1.75 GHz) effective speed.
- Memory Bus Width: 256-bit.
- Memory Type: GDDR6.
Using the calculator on this page, the GPU has a memory bandwidth of 112 GB/s.
GPU Clock Speed and Bus Width Table
Below is a table of typical GPU memory types and their corresponding memory speeds and bandwidth capabilities (measured in gigabytes per second, GB/s), based on commonly used specifications for each type of memory:
| Memory Type | Base Clock Speed (GHz) | Typical Bus Width (bits) | Typical Bandwidth Range (GB/s) |
|---|---|---|---|
| GDDR3 | 0.8 – 1.0 GHz | 64 – 256 bits | 12.8 – 64 GB/s |
| GDDR5 | 1.0 – 2.0 GHz | 128 – 384 bits | 64 – 384 GB/s |
| GDDR5X | 1.5 – 2.0 GHz | 256 – 384 bits | 320 – 576 GB/s |
| GDDR6 | 1.75 – 2.0 GHz | 128 – 384 bits | 224 – 768 GB/s |
| GDDR6X | 2.0 – 2.5 GHz | 256 – 384 bits | 576 – 1008 GB/s |
| HBM | 0.5 – 1.0 GHz | 1024 bits | 128 – 256 GB/s |
| HBM2 | 1.0 – 2.0 GHz | 1024 – 4096 bits | 256 – 1024 GB/s |
| HBM3 | 1.5 – 2.5 GHz | 4096 bits | 1024 – 1638 GB/s |
Explanation of Columns
- Memory Type: The type of memory used in GPUs, each designed for specific performance requirements.
- Base Clock Speed: The raw clock speed of the memory modules.
- Bus Width: The width of the data bus, indicating how much data can be transferred per cycle.
- Bandwidth Range: The typical data transfer speed for GPUs using this memory type.
Why GPU Memory Bandwidth Matters
- Graphics Rendering: High bandwidth ensures smooth rendering of high-resolution textures and complex scenes.
- Compute Workloads: Applications like AI training and scientific simulations require rapid data movement to avoid bottlenecks.
- Gaming Performance: Memory bandwidth impacts frame rates, especially in games with detailed environments or large textures.
- Video Processing: Tasks like 4K video encoding/decoding rely on high memory bandwidth for seamless performance.