Speaking for DeviceAtlas in particular I can assure you that detection reliability is better than most assume. The stated 99% detection accuracy rate isn’t marketing speak—it is continously verified on real traffic from all around the world.<p>We measure two main aspects of performance:<p>- <i>Per-request detection overhead</i>: Willy’s preferred way to measure impact on HAProxy performance is the per request overhead added. DeviceAtlas adds a few µs per request. Typically this does not cause much of an issue. Example: if a load balancer is serving 20,000 requests per second with 80% CPU, that&#x27;s 40µs of CPU time per request on a machine that can
go up to 50µs. If we add 4µs to that we reach 88% of CPU under the same load, and the end user performance is not degraded in any meaningful way.<p>- <i>Memory footprint</i>: DeviceAtlas lets you configure the per-device property set to tailor the memory and performance impact. The resulting memory impact ranges from about 12MB to 100MB.