Choosing a VPS: Key Criteria for CPU, RAM, Storage, and SLA
By The Atlas Hoster team5 min read
Choosing a VPS means learning to read a technical specification sheet and understanding what each line means: vCPU, RAM, disk, bandwidth, SLA. Here are the criteria that truly matter, to select a configuration suited to your workload without overpaying.
Choosing a VPS: reading the specs (vCPU, RAM, SSD, bandwidth)
A VPS spec sheet is read in four numbers. The vCPU measures computing power: the more there are, the more requests the server can process in parallel. RAM, in GB, hosts your applications in memory; when it is full, the server slows down. The disk — SSD or NVMe — stores the operating system and data. Bandwidth sets the volume of data exchanged: often unlimited at Atlas Hoster, with a 1 Gbit/s connection. To discover the details of Atlas Hoster's first configuration (8 vCPU, 8 GB RAM, 40 GB SSD), see our pricing.
Dedicated or shared core: why it makes all the difference
Not all vCPUs are created equal. With a "budget" host, cores are overbooked: multiple clients share the same physical core, and your power depends on your neighbors' activity. A dedicated core, on the other hand, is reserved for you: your computing capacity is guaranteed, stable, and predictable. The spec sheet should state this explicitly — at Atlas Hoster, each VPS displays "100% guaranteed CPU" and "Dedicated core." This is precisely what distinguishes a reliable VPS from a cheap one.
Estimating your application's RAM
RAM is the resource that fills up first. Add up what your stack consumes: the system (a few hundred MB), the web server, the language (PHP, Node.js…), the database, and the cache. A simple WordPress site fits in 2 to 4 GB; a shop with cache and database requires at least 8 GB; an application combining several services requires 16 GB or more. Always keep a 20 to 30% margin to absorb spikes. The complete method is detailed in our article sizing your VPS.
To estimate without a tool: run your application on your current hosting and check the memory consumed under real conditions, a value that most control panels display. Add the cache and database, then your safety margin. It is better to start a bit high and adjust later than the other way around.
NVMe and replicated storage
The disk type directly impacts speed: NVMe is several times faster than a standard SATA SSD, and incomparable to a mechanical disk. Beyond the type, look at replication: replicated storage copies your data across multiple disks, so that a hardware failure does not take them down. This is a criterion that does not always appear on the spec sheet, but it protects your work — Atlas Hoster's VPS are based on replicated NVMe.
SLA and monitoring: the assurance of being online
The SLA (Service Level Agreement) commits the host to a level of availability. At Atlas Hoster, it is 99.9% per month for VPS, measured on the infrastructure — network, hypervisor, storage, power supply. Concretely, if the commitment is not met, a credit is due: 10% of the monthly fee under 99.9% availability, 25% under 99.0%, 50% under 95%. 24/7 monitoring complements the commitment by detecting failures before you do. What these numbers really mean deserves to be decoded: see our SLA explanation.
Finally, keep in mind that the SLA commits the host, not your application: a poorly configured server can go down even if the infrastructure meets its commitments. This is why monitoring and backups remain your responsibility in self-service — or can be delegated to managed hosting.
Managed or self-service VPS
A VPS can be ordered as self-service — you manage everything — or managed, where the host handles updates, security, backups, and interventions. Choose based on your skills: without a technical team, managed hosting avoids the scenario of an unupdated server becoming a liability. Atlas Hoster offers managed hosting as an option on its VPS, at the same tiers as for other offers.
Between the two, there is a compromise: take the VPS as self-service to keep control, then activate managed hosting for tasks you no longer wish to manage — security updates, backups. Most hosts allow you to add managed hosting to an existing VPS without recreating everything.
Pitfalls to avoid
Comparing vCPUs from different hosts without checking if they are dedicated or overbooked: eight shared cores can be slower than two dedicated cores. Taking too little RAM: this is the resource that fills up first, and a server saturated with memory slows everything down. Ignoring the disk type: a mechanical disk severely penalizes a database, whereas NVMe makes the difference. And neglecting the SLA: without a written availability commitment, you have no recourse in case of repeated outages.
Frequently asked questions
How much RAM for a WordPress site?
2 to 4 GB are sufficient for a brochure site or a blog. A WooCommerce shop is more comfortable with 8 GB, especially with cache and an active database. An application combining several services (web, database, cache, queues) often requires 16 GB or more. Always keep a 20 to 30% margin for spikes.
What is the difference between shared and dedicated core?
A shared core is overbooked: multiple clients share the same physical core, and your power varies depending on your neighbors' activity. A dedicated core is reserved for you: your computing capacity is guaranteed, stable, and predictable. This is essential for a production application, where unpredictable latency is immediately noticeable.
Does the 99.9% SLA cover my application?
No. The SLA covers the host's infrastructure — network, hypervisor, storage, power supply — not failures related to your configuration or code. A poorly configured server can go down even if the host meets its commitments. This is why monitoring and backups are your responsibility in self-service, or can be delegated to managed hosting.
To go further: what is a VPS, VPS or shared hosting and VPS price in Morocco. For practical advice, our help explains ordering options (SSL, IP, backup) and upgrading your plan.
Ready to compare configurations? View our Cloud VPS offers and their detailed spec sheets.