The ADATA Ultimate SU750 1TB SSD Review: Realtek Does Storage, Part 1
by Billy Tallis on December 6, 2019 8:00 AM ESTAnandTech Storage Bench - Heavy
Our Heavy storage benchmark is proportionally more write-heavy than The Destroyer, but much shorter overall. The total writes in the Heavy test aren't enough to fill the drive, so performance never drops down to steady state. This test is far more representative of a power user's day to day usage, and is heavily influenced by the drive's peak performance. The Heavy workload test details can be found here. This test is run twice, once on a freshly erased drive and once after filling the drive with sequential writes.
The empty-drive performance of the ADATA Ultimate SU750 on the Heavy test approaches that of the mainstream SATA SSDs, but when the test is run on a full drive its performance drops down to be on par with the other entry-level drives: the Toshiba TR200 DRAMless TLC SSD, and the Samsung 860 QVO with QLC NAND.
The average and 99th percentile latency scores repeat the same story: the SU750 handles the Heavy test well when run on an empty drive, but when full it struggles like other entry-level drives.
The average write latency for the SU750 on the Heavy test shows a much larger full-drive performance penalty than the average read latency scores, but in either case it comes out well ahead of the other two entry-level SATA drives.
The 99th percentile read and write latencies from the SU750 are both competitive with mainstream SATA drives when the test is run on a full drive. When full, the 99th percentile read latency on the SU750 takes a hit that makes it slightly slower than the Toshiba TR200. For writes, the SU750's QoS is hurt quite a bit more, but the TR200 shows just how bad things could have been.
Power consumption is again pretty high for the SU750, especially for the full-drive test run. The two NVMe drives somewhat obscure the big gap that separates the SU750 and 860 QVO from the rest of the SATA SSDs.
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Billy Tallis - Saturday, December 7, 2019 - link
SSDs need to keep track of what physical location each logical block address is stored at. This info changes constantly because flash memory needs wear leveling, and this info needs to be accessed for every read or write operation the host system issues. Most SSDs use a flash translation layer that deals with 4kB chunks, which means the full address mapping table requires 1GB for each 1TB of storage. Mainstream SSDs use DRAM to hold this table, because it's much faster than doing an extra flash read before each read or write operation can be completed. DRAMless SSDs can cache a small portion of that table (typically a few MBs or tens of MBs) within the controller itself or using the NVMe Host Memory Buffer feature.DRAMless SSDs can work as a boot drive, but they're slower than mainstream drives that have the full 1GB per 1TB DRAM buffer.
PaulHoule - Tuesday, December 10, 2019 - link
The block size of an SSD is usually larger than the block size presented to the OS. The SSD can only erase a large group of blocks at once, so it has a flash translation layer that needs to keep track of things like "Block X seen by the OS is really stored in Subblock Y of Physical Block Z". It has to access that data every time it reads or writes, so it helps for that data to be in DRAM.DRAM is also good for write caching; under ordinary circumstances it is a big performance win to buffer writes to RAM before you really do them so you can bundle writes so the SSD can do them efficiently.
Current DRAMless SSDs keep the lookup tables on the SSD itself, which is slower than RAM.
There is a standard for an NVMe device to steal some RAM from the host, which might be a good option. Also there is a standard for NVMe zoned namespaces which would let the host manage the drive more directly, put that together with a revolution in the OS and you could get something which is simple, high performance, and cheap, but that revolution is happening in the data center now, not at the client.
Goodspike - Saturday, December 7, 2019 - link
What's with these brand names?To me Adata means no data. Sandisk means without disk. These are not good names for storage devices!
Gills - Saturday, December 7, 2019 - link
Realtek abandoned me on Windows 10 sound drivers for the many Toshiba POS terminals I'm tasked with updating from Windows XP and 7, so I'm not jumping onboard with anything they do anytime soon.supdawgwtfd - Saturday, December 7, 2019 - link
So going from one unsupported EOL O/S to another soon to be?That doesn't seem like good management.
Gills - Saturday, December 7, 2019 - link
Worded that poorly, sorry - we're upgrading everything to Windows 10.FunBunny2 - Saturday, December 7, 2019 - link
"So going from one unsupported EOL O/S to another soon to be?That doesn't seem like good management."
spend some time as the 'IT manager' at any small business; this sort of driving the infrastructure into the ground is SoP.
PeachNCream - Monday, December 9, 2019 - link
To be completely fair to RealTek, if your company's point-of-sale hardware originally shipped with XP, writing Win10 drivers for that audio hardware was probably not high on anyone's list of priorities. For point-of-sale computers manufactured and shipped with Windows 7, that might be more of a problem given the less obsolete nature of the equipment and yes, I understand that POS systems are expected to have a long service life, but XP was first up for sale in late 2001 and extended suport ended in 2014.Billy Tallis - Monday, December 9, 2019 - link
FYI, extended support for the last POS edition of XP only ended 8 months ago.PeachNCream - Tuesday, December 10, 2019 - link
Ah thanks. I didn't realize that POS variants had a longer support lifespan.