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Overview of 

(Global Storage, HGST) SSD drives


I'm a big fan of the Hitachi SSD portfolio, since they deliver incredible performance and high endurance / reliability. If you compare to the Samsung SSD Guide you'll see that Samsung has almost no offerings that can beat even the slowest Hitachi (HGST) model. Once you compare the important steady state performance, you'll see. The other thing that is nice about Hitachi is that their controllers excel in low latency and especially no latency spikes.

Many cheaper server SSDs will normally deliver nice sub-1ms access times and then, sometimes spike to 300ms and above. Hitachi simply doesn't do this. has a nice graph showing this.

There are a LOT of SSDs in this table since HGST bought sTEC inc, one of the specialized server/embedded SSD vendors and took over their portfolio. They also aquired Virident, responsible for the FlashMax SSD series, which is now also a core part of the HGST SSD portfolio.

Recommendation to Hitachi:

Reduce the portfolio to 1/3. :)


How to read

(10k) - Number from a datasheet if it is different from either brochures, other datasheets or benchmarks.

6k-15k - Lower number for smaller capacity models, higher number for 460GB+ models that have full internal bandwidth.

Write IO/s in steady state - Look at this column for intense use / if you need stable operation with few latency spikes.

Any datasheet and brochures I could find is linked to (hover over the SSD model).


Hitachi SSD Overview

Model / brochure & datasheet linkInterface TypeLink SpeedFlash Technology




(Petabytes written)

Read MB/sWrite MB/sRead IO/sWrite IO/sWrite IO/s in steady stateCache ProtectionOEM only modelBest use
SSD400M BrochureSAS dualport

6G x2


SSD400S.B BrochureSAS dualport

6G x2





FC 4gbitdualportSLC100-4009-35385335410002100021000yesnoSAN



SAS dualport

12G (redundant)

6G (active/active)

eMLC250-10000.9-3.712007001450002000020000yes, proprietary magicno 
SSD1600MR BrochureSAS dualport

12G (redundant)

6G (active/active)

eMLC250-16000.9-5.8 (1.2-5.8)11007001300003000030000?yes, proprietary magicno 
SSD1600MM BrochureSAS dualport

12G (redundant)

6G (active/active)

eMLC200-16003.6-29.21100765130000100000100000?yes, proprietary magicno 
SSD800MM BrochureSAS dualport

12G (redundant)

6G (active/active)

eMLC200-8003.7-14.611507001450007000065000?yes, proprietary magicno 
SSD800MH BrochureSAS dualport

12G (redundant)

6G (active/active)

eMLC200-8009.1-36.51200750145000100000100000?yes, proprietary magicno 



SAS dualport

12G (redundant)

6G (active/active)

eMLC100-8009.1-36.51100765130000110000110000?yes, proprietary magicno 
mach16 slimSATA3GNEED INFOS25-50??2451502400050005000?   
s620SATA3GNEED INFOS100102501202250031003100?   
s840 BrochureSAS dualport6GMLC


9-18529453930001950016500 (12000)   
s840z BrochureSAS dualport6G (redundant)NEED INFOS1625  



110000 (max)


"2x better than competition" :)

s841SASHELPNEED INFOS      ???   
s842 BrochureSAS dualport6G 200-2000  530


(2TB model is slowest, 400GB fastest)


65000-84000 (6000-34000)

(2TB model is slowest, 400GB fastest)




SAS dual6G (active/active)DRAM8GBcan't wear out900800100000100000100000yesout of sale 


Brochure s1100 series

PCIe2.0 x4eMLC200-200033-90PB      out of sale 



PCIe2.0 x4eMLC800-2000

"24DWD" for 800,1000 GB

"12DWD" for 1600, 2000GB

1500100079000-9100026000-49000 yes, "Powersafe"  



PCIe2.0 x8NEED INFOS550-4800

1.3-3 DWD

(4800GB Model lowest)


(1100+2200 fastest)


(1100+2200 fastest)

174000-34300027000-5700013000-27000?yes, proprietary  



PCIe3.0 x8NEED INFOS1100-22002 DWD2000-27001000-1400409000-54900030000-5900015000-30000?yes, proprietary  
SN100NVMex4MLC800-32003 DWD2600-30001400-1600634000-743000107000-160000  not in sale yet 
SN150PCIe3.0 x4MLC1600, 32003DWD30001600743000160000  not in sale yet 

Embedded / specialized SSDs are not listed here. Their info is at

A Question mark behind a value means unverified / guess. Since HGST tends to understate their SSDs insance performance, it is possible that none of the models degrade a lot in steady state.

Values in (braces) mean there are different values and (this one is what I found in the official papers)

FlashMAX and Powersafe is a trademark of HGST.



  • MR = Read intensive (low endurance), MM = Mainstream endurance, MH = High endurance
  • Models in lowercase are the former STEC / Zeus portfolio.
  • SSD1600MR: Hitachi re-specified it to 2 drive writes / day (DWD). Source:
  • Note the 6G SAS models are dualported, but according to the datasheets only run this for redundancy, not loadbalanced. Not sure if this is true. iirc the IOPS numbers in some benchmarks increased in dualported mode.
  • Hitachi only lists "MLC", it is to be assumed that they are using eMLC and just very much understating the level of quality.
  • Noteworthy: there are no SLC models in the current lineup. Either the next one is still in the queue, or the current top IO rates are no longer limited by the NAND technology used.
  • SSD400S.B only - there apparently also used to be a SSD400S.A model which can be seen on Ebay. Rumor has it put to EOL very quickly due to FW issues. If you go for the SLC 6G model, check it has a "B" revision. For the MLC model (SSD400M) no such limitations seem to exist.
  • Is a Cache size column relevant?
  • It seems the future of EnhanceIO's commercial cousin has been clarified. There used to be a commercial version sold by STEC Inc, and it has reappared in a August 14 news article...: "HGST’s ServerCache caching software is available immediately for a free 30-day trial, and is available for purchase at an MSRP of $995.00 per physical server."
  • The numbers for the STEC models seem to be all over the place
  • The 840z FAQ states the controller was designed in-house by the HGST engineers with 20 years of experience. At least the 840 has a STEC, not HGST controller. A bit odd
  • ZeusRAM performance can only top out if run in dualport mode. Single Port performance is 30-50% lower, see the brochure about that
  • Storagereview lists up to 800GB capacties for the s840, but HGST only offers the 200 and 400 GB variations. Look to the s842 for a 800GB model.
  • It is possible that HGST relabeled the 2TB models into new series: s840 2TB became s842 and s1120 2TB became s1122.