OliverQueen

The larger cache on the HDD is not the reason. As can see from the attached image here, I have 2 identical WD 4TB HDD's in same system that have 256MB cache (only difference is the serial number as date of manufacture is the same on both). One is detected as an SSD & the other is detected correctly as a HDD! I also have several other HDD's in the system as well with 256MB Cache & they are detected correctly as well. All other drives in the system are detected correctly. Place the drive in another machine & is detected as a HDD by Defraggler & Speccy, as is placing another drive in this system to check also detects correctly (have tried both SATA SSD & HDD to make sure)

Sorry for necromancing this thread but having exactly the same problem with latest version (at time of posting). In the system that the issue is prevalent, there are two identical Western Digital 4TB spinning rust SMR (urghhh!!!) drives installed. One is detected as a HDD & the other as a SSD! Both are identical other than the serial numbers (running same firmware, same brand/type SATA cables (have tried swapping them around as well), etc). The issue seems to be completely random as the other systems I have Defraggler/Speccy installed on correctly identify the drive types in them. My first thought was because this system is running Windows Server 2019 x64 Standard Edition, but after setting up another Windows Server install on another machine that is due to be deployed on my home network as a dedicated Media Server (I have several licenses here for it so may as well make use of them!), but all the HDD's in that machine are detected correctly using the exact same version of Defraggler & same settings for the roll out of it. All the drives are connected to the onboard SATA controllers (4 x Intel & 2 x ASMEDIA) with the misread HDD tried on both controllers to see if that was the issue (both are currently connected to SATA1 & SATA2 on the Intel controller). The boot drive is a SATA SSD (Samsung 840 series) & that is detected as a SSD correctly & the other drives connected are recognised as HDD's - so just this one drive that is detected incorrectly. No other drives have been connected to the system since the OS install apart from the ones installed in it already, which rules out an older drive specification being detected on the port instead of a replaced drives correct specs. The only thing I can think of is that these SMR spinning WD drives support TRIM (even though they are HDD's but that is due to being SMR rather than CMR) & that is confusing the algorithm used in Defraggler/Speccy, but as 2 identical drives with same date of manufacture on them are being detected as both types of drive, then that cannot be the issue. Both drives are configured identically as well so not as if one of the drives has TRIM disabled therefore being detected correctly. According to the specifications for the drive, the model does not have any other memory than the 256MB cache so they are not hybrid drives with NAND flash prefetch cache like some of the spinning HDD's (mostly 2.5" drives but these are 3.5") that came out around the time that SATA SSD's started to become more available. They are also OEM model drives & not shucked externals (the only shucked external 3.5" drives used are detected correctly as well on all the systems here) Other software such as CrystalDiskInfo, CrystalDiskMark, HWINFO, HWMonitor, etc all detect the drive correctly as a HDD so it is strictly a Piriform issue. I did have a license that covered all Piriform software Pro versions with exact same results, so even that is not the issue & the reason why I did not continue with the Pro license as not going to pay money for software that has had the exact same issue for a number of years now (5 years going from the start date of this thread!). Maybe if it worked correctly, I would pay for the Pro licenses.