Nintendo 64 emulation has always been tricky on RK3326 chips. v7 integrates updates to the plugin.
EmuELEC 5.0 and above introduced support for "NG" (Next Generation) devices like the S905X4, but many users reported audio lag and Bluetooth issues. EmuELEC 4.5 v7 is widely regarded as the "Goldilocks" build—new enough to support the X4 chips, but old enough to lack the DRM and audio latency issues of newer builds.