Recent industry research, including the AI Index 2025, shows that hardware selection has become a major factor influencing AI costs, just like model architecture. Training speed, inference efficiency, and infrastructure expenses are increasingly determined by how well compute, memory, and storage are matched to the workload.
In this guide, we discuss the differences between CPU vs. GPU for AI, provide a detailed explanation of how to select VRAM, RAM, and NVMe, and help you determine when VPS, dedicated servers, or dedicated GPU-based setups are the right choice.
The intention is very clear: to help you pick the best server for AI development and build an AI server that supports real workflows without overpaying.
Modern AI work can be classified into four categories:
One rule covers all cases: first define the workload, then validate the limitations of the AI training hardware, and finally make a decision about the server size.
GPUs handle heavy math well, especially when the same operation runs thousands of times in parallel. CPUs, on the other hand, are more comfortable juggling many different tasks at once and responding to complex logic.
The difficult part is deciding which advantage is more important for your workload. The decision is mostly based on the model type you’re using, its size, and your expectations regarding latency and throughput.
Here’s a brief comparison showing the main differences between CPU and GPU servers in most cases. You can use it as a reference point, and then we’ll go into details.
|
Workload/Constraint |
Better on CPU |
Better on GPU |
|
ETL, tokenization, data joins |
✅ Simpler, RAM‑heavy tasks |
– |
|
Classical machine learning (ML) (trees, linear) |
✅ |
– |
|
Small large language model (LLM) inference, quantized 3–7B, modest queries per second (QPS) |
✅ Often acceptable |
✅ When latency matters |
|
Training or fine‑tuning the convolutional neural network or transformer models |
– |
✅ Significant speed‑ups |
|
Diffusion training/generation |
– |
✅ Required for practical speed |
|
High‑throughput inference |
– |
✅ Latency and throughput |
|
Budget per month |
✅ Lower entry point |
✅ Better cost‑per‑result at scale |
A well-provisioned CPU machine can handle more AI than many people realize:
In these cases, you need strong per-core performance, enough RAM for in‑memory datasets, and NVMe storage for spill.
Your AI server CPU requirements: 4–16 vCPU (or more for parallel ETL), RAM sized at 2–3× the largest dataset in memory, and NVMe sustained read/write above your data loader rate.
When you build an AI server for this profile, start with RAM and storage planning; if the pipeline is input/output (I/O)-bound, adding CPUs won’t do anything.
In case your loops involve main operations like matrix multiplications and convolutions, or you increase sequence lengths and batch sizes, switching to a GPU server for AI can save days or even weeks of work. Clear cases include:
Once you’ve decided that your project requires a GPU server for AI, the next step is to determine the amount of VRAM and to select a generation. Usually, performance problems can be traced to one of three factors: insufficient VRAM, low memory bandwidth, or poor intercommunication between GPUs.
VRAM is the first wall you hit: model weights, activations, and optimizer state all have to fit simultaneously. The numbers below are a good reference point.
Text LLMs:
Vision Transformers and Diffusion:
Multi-modal:
Once models get bigger (or if you want longer context without squeezing everything), 48–80 GB is much easier to work with.
When building an AI server, don’t aim for “barely fits.” Leave space for longer sequences and the occasional spike from the data pipeline. That’s what AI model training hardware needs to look like in practice: VRAM is the gatekeeper, then you optimize for bandwidth and storage to keep pace.
Get the most out of your budget with VPS. NVMe drives, 40+ global locations, and flexible configs for any project.
Different GPUs act very differently when it comes to AI workloads:
If your roadmap includes multi‑GPU training, be sure to plan for data/model parallelism in advance. Staging samples from ultra‑fast NVMe and pinning host memory helps keep GPUs busy.
CPUs and GPUs handle computation, but RAM and storage determine how smoothly everything moves around them. When either is undersized, workflows slow down long before compute is fully used.
A quick rule of thumb for AI server CPU requirements is to size the system so data loaders can keep the GPU busy without fighting for cores, while RAM is sufficient to keep prefetch queues full. When GPUs wait on data, you’re paying for capacity that isn’t doing any work.
Training and fine‑tuning are streaming problems. You pull shards, decompress, augment, and batch — over and over. NVMe reduces the distance between disk and GPU memory in practice. Benefits include:
This question shows up early in almost every infrastructure discussion. Rather than starting from specs, it helps to look at how each server type behaves under real workloads.
VPS hosting is a good fit for many AI workflows, especially for model training. It's commonly used for orchestration, data preparation, vector databases, CI/CD pipelines, API gateways, and inference for compact models. VPS environments are also great for experiments with a clear structure, tools used internally, and services that require fast NVMe storage and consistent resources.
On is*hosting, this corresponds to the Start, Medium, Premium, Elite, and Exclusive plans, all of which are powered by up-to-speed NVMe with strictly defined CPU and RAM allocations.
Smaller plans are perfect for lightweight services and pipelines, while Premium and higher tiers give lots of room for more demanding data tasks. Optional control panels like ISPmanager, DirectAdmin, HestiaCP, aaPanel, or cPanel provide easy management of web interfaces and APIs when you want to speed up.
Basically, all scenarios that involve long, uninterrupted CPU‑heavy jobs, larger RAM footprints, specialized networking, and strict isolation are pushing you toward bare metal dedicated servers.
If you expect higher sustained CPU utilization and frequent disk churn, a dedicated server guarantees performance consistency along with the control to upgrade.
It can also be a good partner in the future with external or attached GPUs, if you decide to switch from CPU-first to a GPU server.
At the current scale of deep learning, it’s really difficult to find a substitute for GPUs. A GPU server for AI not only reduces training time but also allows work with massive data batches and long contexts.
Additionally, it’s necessary for workloads related to multi-modality and diffusion. The key challenge here is to provide VRAM and memory bandwidth that correspond with the model so that the hardware is always working at full capacity.
|
Option |
Strengths |
Watch‑outs |
Good for |
|
VPS |
Instant start, NVMe, predictable price, easy scaling |
VRAM not guaranteed; shared host resources by design |
MLOps, data prep, control plane, small‑model inference |
|
Dedicated |
Full control, consistent CPU/RAM/disk, upgrade path |
Lead time, higher monthly cost |
Big ETL, heavy RAM pipelines, stable long‑running services |
|
GPU server for AI |
Massive training/inference speed; tensor cores; large VRAM |
Higher cost; plan around VRAM and interconnect |
Fine‑tuning, diffusion, high‑QPS inference |
Before applying the presets, it’s necessary to identify what the main cause of your delay will be: data preparation, training, or inference. If it’s mostly related to cleaning, tokenizing, and moving files around, then a powerful CPU, sufficient RAM, and fast NVMe will be more appreciated than adding GPUs.
However, if you are fine-tuning or executing heavy generation, start with VRAM and select a GPU server for AI that gives you some flexibility.
Objective: Explore datasets, run baselines, prototype APIs, and try small fine‑tunes.
Objective: Creation of production-grade pipelines, continuous fine-tuning of 7–13B models, and low-latency inference.
Objective: Multi‑GPU training, long context windows, and high‑QPS multi‑modal inference.
Think in cost-per-result, not just monthly price. A GPU server for AI might end up being cheaper overall if it reduces training time from seven days to just one, and allows engineers to deliver faster.
Here are some tips:
It’s important to connect your spending to specific milestones. For instance, you could say: "Launch an inference API with a response time under 150 ms p95" or "Finetune a 13B model to reach X metric." By doing so, hardware will become a lever rather than a guessing game if you measure the right outcomes on your AI training hardware.
For when VPS isn’t enough.
Here’s a checklist that will help you select the best server for AI development without second‑guessing:
Hardware decisions become easier when they are connected to daily operations. Look at what your team is actually doing — like transferring data, running tests, or providing insights — and use that information to dictate the configuration.
Go for a small deployment in areas where it’s sensible, increase capacity in areas where it’s the most demanding, and don’t build "just in case."
A flexible approach — from simple installations to more powerful computers — prevents the infrastructure from being a barrier. If the platform is stable and help is readily available, then it’s possible to remain focused on experiments, results, and actual product delivery.