Why you shouldn’t buy a laptop based purely on its specs

When buying a laptop, we tend to think there’s no stronger indication about how it’s going to perform than its specs sheet. We put so much emphasis on it in our quest to find the fastest, most efficient, and graphically superior product to suit our needs.

But in doing so it’s easy to make a common blunder: To spend a lot of money on a laptop with specs that look great, only to have the device fail to live up to expectations.

I see it all the time in my role as a laptop reviewer. But what’s more, I often see big differences in performance among laptops with the same specs. So…why aren’t specs the best hint to performance? And how can you really tell if a laptop is going to perform well?

Further reading: Best laptops 2024: Premium, budget, gaming, 2-in-1s, and more

Why can laptop performance vary so much?

A lot of factors come into play to vary performance — even among laptops with the same specs. A couple important factors are variations in the CPU and GPU wattages and differences in the laptop size and thickness (design).

To talk to the first point and take GPU wattages as an example, laptops with discrete video cards often have different TGPs, or total graphics power settings. These wattages vary because OEMs like Nvidia and AMD allow laptop manufacturers to set them anywhere within a defined range. For example, a Nvidia GeForce RTX 4070 graphics card can be set at TGPs anywhere between 40W to 140W.

The fact that manufacturers can do this is generally a good thing in that it gives them a lot of wiggle room to find the right power setting for a particular laptop model — one that suits the laptop’s type, power supply, display, battery, and cooling hardware.

A higher TGP is generally better as it allows your laptop’s GPU to work at higher clock speeds, which equals faster performance. In two gaming laptops with the same video card, the one with the higher TGP will quite often produce higher average frames-per-second in games compared with the other.

That’s a bit of a generalization, but you get the gist. To confuse the situation, lower-tier graphics cards with high wattages can sometimes outperform higher-tier graphics cards with low ones.

In Nvidia GPUs, the Dynamic Boost setting can also make a difference. If this is switched on, it adds extra power to the graphics card for some tasks, which can again skew performance results among models further.

How does laptop size have an impact on performance?

A laptop’s size and thickness can affect the thermal headroom, or the time a laptop can maintain its performance level without throttling and overheating (and subsequently slowing down the processing of tasks).

It’s often the case that larger laptops have more space for cooling hardware and therefore heat dissipation than smaller ones — that is, they can fit more fans, air vents, and cooling chambers, or else just have larger components with a higher capacity to cool.

This can allow them to reach higher clock speeds and stay operating at those speeds for longer than smaller, thinner laptops. In smaller laptops, designing and implementing efficient thermal systems requires extensive research and development and careful selection of each part to prevent overheating. Often hardware must be slimmed down or meticulously designed to fit.

In our PCWorld reviews several tests give us an indication of a laptop’s performance capabilities. In our gaming laptops, for example, the 3DMark Time Spy benchmark and the games benchmarks indicate how well a laptop will handle intensive graphics tasks.

Additionally, an encoding test we designed in-house using the free HandBrake utility provides a glimpse of how well a laptop can prevent throttling. In this task, large laptops often fare better than smaller laptops with the same specs.

Further reading: Best gaming laptops 2024: What to look for and highest-rated models

A quick comparison of the performance results from our 14-inch Acer Nitro 14 and 16-inch Acer Nitro V16, shows size-related performance differences playing out.

Although these two laptops have matching AMD Ryzen 7 8845HS and Nvidia GeForce RTX 4060 GPUs, the larger Acer Nitro V16 is the clear winner of the two, outperforming its smaller sibling in both the Shadow of the Tomb Raider game benchmark and PCWorld HandBrake test (see below).

So how can you tell if a laptop will perform well?

Despite what I said about wattage and size, you can never quite tell how a laptop will perform until it’s been properly tested. It’s for that reason I urge you to read our PCWorld laptop reviews where you can find the results of our extensive performance testing, before pulling the trigger and pressing purchase on a laptop.

Our reviewers have done all the hard lifting for you, meticulously testing the performance of the both the CPU and GPU. You can also find performance comparisons with other laptops to make choosing between different brands a lot easier when it’s time to decide. Happy laptop hunting!