Expert Reviews Staff 11 min 9 sec agoPrice when reviewed 1032Measuring 240 x 260 x 111mm, and weighing 4.5kg with its surprisingly bulky external PSU, the QuietPC AMD Sentinel Fanless is large by mini PC standards. That trade-off in size, though, grants you a number of advantages over its more compact competition.Ignoring the optical drive - a DVD-writing slot loader as reviewed, though it can be left off the build list or replaced with a Blu-ray drive - the biggest feature of the Sentinel is the inclusion of a PCI Express x16 slot on the motherboard.READ NEXT: Here are the best mini PCs you can buy right nowQuietPC AMD Sentinel Fanless review: SpecsThis, sadly, isn't quite as useful as it first seems: as well as being limited to 8x operation when an APU is fitted, as in our review model, the case restricts add-in cards to half-height single-slot variants. (An APU, or accelerated processing unit, is AMD's term for a single die that contains both a CPU and GPU.)See related Shuttle DH370 review: A small and useful barebones systemOverclockers Gaming XVI Essential review: An impressive desktop for gamingAPU users are faced with another restriction: although the motherboard includes two NVMe-compatible M.2 slots for storage, only the first of these is available with an APU fitted; the second is automatically disabled to provide PCIe lanes to the integrated graphics on the APU when fitted. With the mid-tier AMD Ryzen 5 2400GE and its integrated Radeon RX Vega 11 graphics processor fitted, as reviewed, performance of the Sentinel was impressive for a wholly fanless design.With the APU connected to the finned Streacom FC8 Alpha case via copper heatpipes, the main reason for the case's extra bulk, the Sentinel kept the chip from overheating even during our demanding multitasking benchmark - in which the Sentinel handily beats all the other passively cooled systems on test. Gaming performance, however, isn't the Sentinel's strong suit.Buy now from QuietPCQuietPC AMD Sentinel Fanless review: PerformanceWhile it managed a playable 44.8fps average in the Unigine Superposition benchmark at the 720p Low preset, higher resolutions and detail settings saw it struggle to hit double figures - although few other systems on test fared much better, and none with the same silent cooling system.The Sentinel's idle power draw, sadly, fails to impress. You would think that a machine with no moving parts would sip power, but we were unable to convince it to drop below 28.6W at the Windows 10 desktop - odd, given that its 101.6W peak power draw under load is reasonable for the performance it offers.Nearly 102W is a lot to be sinking through a passive heatsink, though, even one the size of the entire case. It's no surprise to find that the Sentinel gets toasty under prolonged load conditions, but if you're pushing a system this hard then passive cooling probably isn't for you. These relatively minor issues aside, it's easy to be impressed with the Sentinel.READ NEXT: The Lenovo ThinkCentre M910x Tiny is a small but expensive mini PCQuietPC AMD Sentinel Fanless review: DesignThe QuietPC build has clearly been put together with care, and the Streacom case is top quality. Better still, there's no bloat: QuietPC guarantees a clean installation, promising that it will never pre-install anything not absolutely necessary to the operation of the system, and even includes the original packaging for components like the motherboard should you want to swap it out.QuietPC's warranty is also worthy of mention: as well as covering the machine for two years as standard on a collect-and-return basis, it's what the company calls "open box", meaning you're free to take the lid off your new PC and fiddle around, chopping and changing components as you see fit, and QuietPC will still cover whatever original parts are left.Buy now from QuietPCQuietPC AMD Sentinel Fanless review: FeaturesThere's room for expansion, too: aside from the already-covered PCIe slot and second M.2 slot, there are four on-board SATA connectors and room to mount two 3.5in or three 2.5in drives inside the chassis - though maxing the system out requires an upgraded power supply for an extra £31.There's also a generous eight USB ports: two USB-A 3.1 Gen 1 ports at the front and another four at the rear alongside two high-speed USB-A 3.1 Gen 2 ports, the APU's HDMI output, analogue audio ports with neat colour-coded LED lighting, and a single Gigabit Ethernet port.QuietPC AMD Sentinel Fanless review: VerdictAdd in the front-mounted infrared receiver, and the Sentinel Fanless makes for a tempting home theatre machine - just as long as you don't expect to be running a VR headset from its integrated graphics.QuietPC AMD Sentinel Fanless specificationsProcessorAMD Ryzen 5 2400GERAM8GB DDR4-2666 DIMMFront USB ports2 x USB-A 3.1 Gen 1Rear USB ports2 x USB-A 3.1 Gen 2, 4 xUSB-A 3.1 Gen 1Graphics cardRadeon RX Vega 11Storage500GB, M.2 NVMe/SATA, 4 x SATAOperating systemWindows 10 HomeWarranty2yr "open box" C&R