GPU virtualization makes it possible to run GPU-accelerated workloads inside virtual machines. This allows teams to use familiar VM-based environments for AI inference, model development, rendering, simulations and other compute-intensive tasks.
However, “GPU virtualization” can describe several different technologies. They do not provide the same level of isolation, flexibility or performance.
What Is GPU Virtualization?
In a traditional virtual machine, the guest operating system accesses virtual CPUs, memory, storage and network devices. GPU virtualization adds a physical graphics processor to that environment.
Depending on the architecture, a virtual machine may receive:
- A virtual slice of a physical GPU;
- A hardware-partitioned GPU instance;
- Shared access to GPU resources;
- Or exclusive access to an entire physical GPU.
This difference is important because a GPU’s memory allocation does not always mean that the VM has exclusive access to GPU compute resources.
1. NVIDIA vGPU
NVIDIA vGPU divides a physical GPU into multiple virtual GPU profiles. Each VM receives a defined amount of GPU memory and a virtual GPU device.
This approach is useful when several users or applications need access to the same physical GPU. It can improve resource utilisation, but it usually requires:
- Supported NVIDIA hardware;
- A compatible hypervisor;
- Supported guest operating systems;
- NVIDIA vGPU software and licensing;
- Careful capacity planning.
vGPU is often suitable for enterprise virtual desktop infrastructure, shared AI environments and multi-user workloads. However, it is not the same as assigning a complete physical GPU to one customer.
2. NVIDIA MIG
Multi-Instance GPU, or MIG, creates isolated hardware instances on supported NVIDIA data-centre GPUs. Each instance receives a defined portion of GPU memory and compute resources.
MIG can provide stronger isolation than ordinary time-sharing because each instance has dedicated hardware resources. It is useful for running multiple smaller inference workloads on one high-end GPU.
The trade-off is flexibility. Applications must fit the selected MIG profile, and workloads that require multiple GPUs may need a different architecture. MIG is also available only on compatible GPU models.
3. Hyper-V GPU-PV
GPU Paravirtualization, commonly used with Windows Hyper-V, allows virtual machines to access GPU acceleration through a paravirtualized interface.
This can be useful for Windows applications, remote workstations, rendering and development environments. However, GPU compute and memory may still be shared depending on the configuration. It should not automatically be described as equivalent to a dedicated physical GPU.
Teams should confirm the supported Windows version, GPU driver, workload type and resource allocation policy before deployment.
4. PCIe GPU Passthrough
PCIe passthrough assigns an entire physical GPU directly to one virtual machine. The guest operating system can install its own drivers and access the GPU with minimal virtualization overhead.
This approach is often preferred for:
- AI inference;
- Model fine-tuning;
- 3D rendering;
- Video processing;
- Scientific computing;
- Applications requiring full CUDA compatibility.
The main limitation is that the assigned GPU cannot normally be shared with another VM. Standard passthrough may also limit live migration and certain high-availability features.
Why GPU Isolation Matters
Two plans may both advertise the same GPU model but deliver different experiences.
A time-shared GPU can be cost-effective for short or variable workloads. A dedicated GPU may be more appropriate for long-running inference, production services or workloads with predictable performance requirements.
Before choosing a plan, customers should ask:
- Is the GPU shared, partitioned or fully assigned?
- Is GPU memory reserved for the VM?
- Can another tenant affect GPU performance?
- Which drivers and CUDA versions are supported?
- Can the VM run both Linux and Windows workloads?
- Are there licensing requirements?
- Is live migration supported?
- Are CPU, RAM and storage resources also isolated?
How GPU Mart Uses PCIe Passthrough
GPU Mart uses KVM virtualization combined with PCIe GPU passthrough for its GPU VPS configurations. Each instance receives access to a complete physical GPU rather than a time-sliced GPU partition.
This allows customers to maintain their own guest operating system and driver environment while using the GPU with near-native performance. The approach is designed for AI inference, fine-tuning, rendering and other workloads that require predictable GPU access.
GPU Mart also offers GPU dedicated servers for customers that need full control of the physical machine, multiple GPUs or advanced virtualization configurations. More technical details are available on the GPU virtualization solutions page.
Choosing the Right Architecture
- Choose vGPU when multiple VMs need flexible access to one supported GPU.
- Choose MIG when smaller, isolated workloads can fit predefined hardware profiles.
- Choose GPU-PV for compatible Windows virtualization scenarios.
- Choose PCIe passthrough when one VM needs exclusive access to a full GPU.
- Choose a dedicated GPU server when you need complete host-level control or multiple GPUs.
GPU virtualization is not a single technology. Understanding how GPU resources are allocated is essential for comparing providers and avoiding misleading performance assumptions. The most important question is not simply which GPU model is offered, but how that GPU is assigned, isolated and made available to the workload.
