Guide: Deciding between a high-end laptop and a desktop PC

Laptops are very constrained when it comes to thermals. Therefore, companies such as Intel and AMD design mobile variants of their desktop counterparts with lower TDP ceilings, better energy efficiency, and more power-saving features designed to maximize battery life. Although this does not greatly impact regular workflows, these processors do suffer a performance penalty compared to their desktop counterparts.

While H-series processors (35 - 45 W TDP) are usually the staple of enthusiast creator and gaming laptops, there are several true desktop replacements with actual socketed desktop processors. A prominent example that comes to mind is the MSI GT76 Titan that features a desktop Intel Core i9-9900K that is overclocked on all eight cores to 5 GHz. There's also the Schenker XMG Apex 15, which houses up to a full 16-core, 32-thread AMD Ryzen 9 3950X processor on a custom AMD B450 motherboard.

Desktop replacement laptops such as the Alienware Area-51m and Eurocom Sky X4C offer the ability to swap-out the discrete GPU, allowing for future upgrades without having to ditch the entire laptop. Such laptops offer the GPU on a Mobile PCI Express Module (MXM) or a proprietary solution such as the Dell Graphics Form Factor (DGFF), which can be swapped out as and when is needed. If the laptop's CPU offers integrated graphics (and most of them do), then you can still get display output via the iGPU even if the discrete GPU goes kaput. However, things aren't as simple as they seem.

If you do opt for a fairly high-end notebook but still prefer the flexibility of GPU swapping as and when is needed, an external GPU (eGPU) setup may be worth looking at. eGPUs are enclosures that house a full desktop graphics and can connect to the laptop via Thunderbolt 3 port, offering a neat way to add additional graphics horsepower when desired. However, there are some limitations to be aware of with this setup.

Thunderbolt 3 offers an effective 40 Gbps of PCIe bandwidth. In that, a maximum of 32 Gbps can be used for non-video PCIe data while 8 Gbps is reserved for display output. Although 32 Gbps of available PCIe bandwidth is nothing to scoff at, it is still less than what a PCIe x16 bus offers in a desktop or even in an internal laptop implementation. 

Due to the bandwidth limitations of Thunderbolt 3, it may not be really wise to spend on more beyond a GeForce GTX 1080 GPU. Also, assuming that the display is a 10-bit 60 Hz panel, any resolution above 2.5K (2560x1600) can eat up into the 32 Gbps regular data bandwidth of the Thunderbolt 3 interface, resulting in even lesser performance.

Do check out our article "eGPUs still aren't worth it, right?" for more insights.

Desktop replacement notebooks come with RAM that is smaller than your typical PC RAM module. RAM modules used in laptops are called small outline dual in-line memory modules (SO-DIMMs) and feature 260 pins. Desktops use standard DIMMs, which have 280 pins. While desktop RAM cannot be installed in a laptop, modern laptop SO-DIMMs offer a similar choice of capacities, frequencies, and timings as their desktop DIMM counterparts.

However, one thing to be kept in mind is the expandability. Laptops, even the desktop replacement varieties, mostly offer only two memory slots, with a few such as the MSI GT76 offering up to four. Some even have part of the memory soldered on to the motherboard. Desktops, on the other hand, offer at least two slots (small form factor PCs) and can go up to eight slots in total (HEDT setups). Laptops also tend to enforce memory capacity limitations in the BIOS. For instance, the Schenker XMG Apex 15 powered by the Ryzen 9 3950X supports only up to 64 GB of DDR4-3200 RAM whereas desktops powered by the same processor can support up to 128 GB of DDR4-4200 or even higher. Desktop BIOSes also allow for setting XMP profiles, overclocking memory, and tightening RAM timings — something that may be hard to achieve on a laptop.

Desktops also have an aesthetic advantage, if you are really into that. Many RAM modules come with built-in RGB designs that look great, especially in tempered glass cabinets.

So, if you are looking for the absolute best performance when it comes to memory, desktops are the only option. That is not to say that laptop variants are bad. Just that there are some limitations in terms of expandability and tweaking that you should be aware of if you plan on running highly memory-intensive applications. For the most part, such limitations do not usually have a drastic affect on your workflow.

Unlike other components, the storage subsystem remains unchanged across both laptops and desktops, unless you are into 3.5-inch hard drives. M.2 NVMe drives offer the best performance and modern high-end laptops come with at least one or sometimes even two M.2 slots offering RAID possibilities. Users are often given the choice of opting for 2.5-inch SATA hard drives or SSDs during configuration. Mixing and matching SSDs and HDDs can offer the right combination of storage capacity and performance. Of course, with desktops, you get even more storage expansion bays but for the vast majority of work, the available storage options in high-end gaming and workstation laptops should fit the bill.

No matter how large the notebook chassis is, its thermal performance will almost always be inferior to that of a full-fledged desktop PC. A desktop also allows you to use AiO liquid cooling or custom water loops to further lower temperatures and add that extra pizzazz to the build. Back in the day, Asus toyed with the concept of liquid cooling in a laptop with the ROG GX800VH, but that design was too clunky for practical use and the laptop itself was priced out of reach for most buyers. 

Nowadays, we find laptops with a decent set of heat pipes and better fans. For instance, the MSI GT76 Titan comes with a staggering 11 heat pipes to keep the socketed Core i9-9900K cool. Laptops such as the Razer Blade Pro 17 and Asus ROG G752VY use vapor chambers instead of heat pipes to provide more reliable cooling, though it does make the device a tad heavy. 

Check out the following article for more in-depth information on how laptop cooling solutions are designed:

• Laptops 101: Understanding what goes into designing an efficient laptop cooling solution

Port selection is another aspect that should be factored-in while deciding between a desktop replacement notebook and a proper desktop PC. Most high-end gaming laptops and desktop replacements offer a fairly decent choice of ports. Intel-based gaming laptops usually offer at least one Thunderbolt 3 port that should allow for even more expandability while also facilitating connecting multiple monitors at the same time. However, desktops usually have the upper hand when it comes to sheer number of ports. Apart from offering a copious number of USB ports of all standards, desktop motherboards also have additional headers to connect chassis USB and audio ports. 

Modern desktops also integrate built-in diagnostics and a dedicated CMOS flashback/BIOS reset switch that can help recover your PC in case of a failed overclock or incorrect BIOS settings. High-end notebooks also offer a way to reset the BIOS, but it is not as straightforward as it is on a desktop. For the most part, notebook BIOSes have limited customization options vis-à-vis their desktop counterparts with the user often being dependent on OEM tuning software or third-party tools.