Hummm, strange one here, updated two S3/B4's and two S3/B5's to latest firmware this morning, all went well and initially all four will hash at 500GH/s using 250M... however after a while (30 mins or so) one of the S3/B5's always drops back to 458GH/s (from 500)..? There are no x's or -'s, as per screen shot...
One Seasonic X-1050 PSU for each pair of miners...
