DDR5 has much greater bandwidth, but as it runs in gear 2 it gets much worse latency. That's why DDR5 machines get much worse 1% lows. So long as the assets are kept in the CPU cache it doesn't matter, but the moment you need to page the ram, you get jarring fps dips. Of course the 1% lows are the exact moment when interesting things happen.(like in a gunfight)
Co-incidentally it's the same reason that the 5800X3D is so much better than every other AMD CPU - huge cache, so it doesn't get the typical AMD FPS drops.