On my 8 year old desktop system (8GB ram, 2.5GHz AMD Phenon II) it feels subjectively faster than Evince because of better UI latency. Resource-intensive is a good thing if the resources are used effectively, eg. for more aggressive speculative rendering, which seems to be the case. On mobile I might care a little more, but the forced animation in Evince (and a growing number of GNOME apps) is a deal-breaker, so I'd prefer Okular even on mobile.