Just got the first two, which will be used as parities, since they are larger than current ones, will need to do a double parity swap, not surprisingly they look exactly the same, except the sticker, they also weigh the same, was hoping for a small difference to confirm they actually have different internals, obviously weighting the same doesn't prove they don't, also my scale resolution is 5g, so there might be a very small difference unmeasurable by me, I guess time will tell if they have better vibration protection, though Toshiba recommends theses disks for 1 to 8 bays and they will be used on a 21 disk server, but if nothing else they will have an extra year of warranty. On that note some good news, one of two failed 4TB WD is still under warranty, so not a total loss, before checking the serials I was thinking they were both out of warranty since they were some of the first 4TB disks on that server.