Two conventions are in use. They cannot be ranked together. Apple and Dell declare the mean sound power, LWA,m, and print the statistical adder KV separately. HP and Lenovo declare an upper limit, LWAd or LWA,c, with the adder built in. Every pick names its convention for that reason. Our explainer on sound power versus sound pressure unpacks bels and KV.
Here is every idle declaration we found, split the same way.
| Desktop | Convention | Sound power at idle | Operator position at idle |
|---|
| Apple Mac Studio (M5 Ultra as tested) | Mean, KV separate | 1.5 B (KV = 0.3) | 7 dB |
| Apple iMac 24, two ports | Mean, KV separate | 1.6 B (KV = 0.3) | 5 dB |
| Apple iMac 24, four ports | Mean, KV separate | 1.7 B | 7 dB |
| Dell 27 all-in-one | Mean, KV separate | 2.5 B | 17.2 dB |
| Dell Pro Tower | Mean, KV separate | 2.8 B | |
| Dell Pro Precision 7 T1 | Mean, KV 0.4 | 2.9 B | 16.3 to 16.7 dB across modes |
| Dell Pro Slim | Mean, KV separate | 3.24 B | 25.4 dB |
| Dell Alienware Aurora | Mean, KV separate | 3.36 B | |
| Dell Tower | Mean, KV separate | 3.7 B | 24.1 dB |
| Lenovo ThinkCentre M90a Pro Gen 6 | Upper limit, KV included | 2.04 B | 12.49 dB |
| Lenovo ThinkCentre M90a Gen 6 | Upper limit, KV included | 2.23 B | 11.04 dB |
| Lenovo ThinkCentre neo 50a 27 Gen 6 | Upper limit, KV included | 2.6 B | 16.4 dB |
| Lenovo Yoga AIO 27i Gen 10 | Upper limit, KV included | 2.7 B | 18.3 dB |
| HP EliteStudio 8 AIO | Upper limit, KV included | 2.8 B | 14 dB |
| HP ProStudio 4 AIO | Upper limit, KV included | 2.8 B | 14 dB |
| Lenovo ThinkCentre M90t Gen 6 | Upper limit, KV included | 3 B | |
| HP EliteDesk 8 Tower | Upper limit, KV included | 3.0 B | 21 dB |
| HP EliteDesk 8 SFF | Upper limit, KV included | 3.1 B | |
| Lenovo ThinkCentre M70s Gen 6 | Upper limit, KV included | 3.1 B | |
A blank cell means no operator figure is recorded here. At idle, most desktops sit within a bel of each other.
Which desktop PCs stay quiet under full load?
Dell's Pro Precision 7 T1 workstation declares 2.9 bels at idle and 2.9 with its Core Ultra 9 fully stressed. Lenovo's neo 50a 27 all-in-one rises only from 2.6 to 2.7.
Only Dell and Lenovo declare a processor load mode at all, and once they do, the spread opens.
| Desktop | Idle | CPU load or stressed |
|---|
| Dell Pro Precision 7 T1 | 2.9 B | 2.9 B |
| Dell Pro Tower | 2.8 B | 3.7 B |
| Lenovo neo 50a 27 Gen 6 | 2.6 B | 2.7 B, 18.6 dB |
| Lenovo M90t Gen 6 | 3 B | 3.2 B |
| Lenovo M70s Gen 6 | 3.1 B | 3.3 B |
| Lenovo M90a Pro Gen 6 | 2.04 B | "N/A" |
Look at the Dell pair. The Pro Tower shares a regulatory platform with the workstation, starts a tenth of a bel lower at idle, and finishes 0.8 higher under CPU stress. Apple declares idle and a web browsing test. HP declares idle and disk activity. Neither says what its desktops sound like under full load, and the absence of a figure is not proof of anything either way.
If you build your own instead, our PC case and CPU cooler guides cover the parts whose fans set the noise under load.
Dell's Pro Slim declares 3.24 bels at idle against 2.8 for the Pro Tower. Lenovo shows the same pattern, 3.1 for the small M70s against 3 for its M90t tower.
Small cases carry small fans that spin faster, and the figures reflect it, so on both makers' sheets the compact model turns out to be the louder half of the pair, which is the opposite of what a buyer shopping for a small quiet box might expect. For the quietest compact option, our mini PC guide goes smaller still, where the Mac mini declares even lower.
An optical drive is the loudest mode on any sheet
Dell's workstation datasheet puts its optical drive mode at 4.9 bels and 39.1 dB at the operator position, against 2.9 bels at idle. No desktop declaration here prints a higher figure.
Anyone who still needs discs and wants quiet should use an external drive only when needed.
HP's list prices run far above street
The EliteDesk 8 SFF lists at $3,880 on HP's store, while Amazon sellers offer it for much less, and the configured EliteStudio 8 all-in-one lists at $3,194. HP's consumer OmniDesk and OmniStudio pages publish no noise figure at all. Two familiar names are missing for other reasons: Apple's Mac Pro is discontinued, and Dell has no current XPS desktop.
