Boot Times, Game Loads, Cache Rolloff
Boot Times
We already know that SSHD's speed up boot times and other operations, but we've had several readers question the ability of that cached data to stay put over time. With such a small cache, the theory was that unless you are only repeating the same sort of operation, much of the advantage is not seen. Let's see how this all pans out with some attempts to observe data rolling off of the cache:
I'll walk you through this data below:
- 1-5: Repeated reboots timed on the test bed running on a pure SSD setup.
- 6-10: After cloning the disk to the SSHD, we timed 5 sequential reboots. The first reboot takes longest as none of the OS data has been cached. You can see boot times steadily drop to very close to SSD speeds.
- 11-14: Battlefield 4 is installed and run for the first time (launched using string '-level Levels/SP/SP_Dam/SP_Dam' and timed from game launch until we were first allowed to 'ESC' past the level intro scene). We repeated this launch a few times to get a steady state value, and we see caching shave nearly 20 seconds off what would have been a 50+ second level load.
- 15: We rebooted the system, noting that the reboot time returned to the uncached speed.
- 16-18: Here we see the attempted caching of the reboot data (15) pushed some of the BF4 level data out of the cache, adding 6 seconds to the level load time on its first pass. Subsequent passes returned to the faster speeds.
- 19-22: Here we tried a few reboot passes. This time the first reboot was not hit as hard as the previous time (15), as this time we did not install the game, but only ran it a few times.
- 23-25: Another round of BF4 loads, effect similar to last time.
- 26-30: Another round of reboots. This time we did a few more, as for some reason the cache did not snap back as quickly as it had on previous rounds.
- 31-33: Final round of BF4 loads was similar to prior runs, but it appears the cache started to get a bit confused near the end, especially when looking at the weirdness that happened during the last round of reboots (26-30).
End result: 8GB of cache was not sufficient, as just launching a single game was enough activity to force previous data to be purged. Basically, doing a few other things with your PC will purge previous data out of the SSHD cache, and once you get back to the original thing (i.e. a reboot), you will mostly return to the (relatively slow) HDD performance. That reboot itself will purge some other data that was cached, so once that reboot has completed, re-launching your previous applications will also be slower than they could have been. Rinse and repeat. This effect could have been mitigated with the inclusion of a larger cache on these desktop-class devices.
Would be good to see the
Would be good to see the drive performance after the whole of the flash cache has died and to see how long the flash lasts.
Even though it is small, the
Even though it is small, the cache will very likely outlast the mechanical portion of the drive.
Can i use Intel’s SRT with a
Can i use Intel’s SRT with a RAID array? One Samsung 840 pro for the OS and two WD RED in RAID 1 with a cheap 64GB SSD for caching for the array.
I haven’t tested that
I haven't tested that specific config, but I believe you can use SRT caching on a RAIDed pair.
Just bought two 5TB drives
Just bought two 5TB drives for $189 each. Doesn’t seem that the performance gain is worth the loss of capacity.
Hi,
What 5TB drives did you
Hi,
What 5TB drives did you get? and where did you purchase them? That price sounds really good, I’m looking to put in a couple bigger drives in my rig that I can run in Raid.
Thanks.
Mark
Just bought a third. 32TB
Just bought a third. 32TB and three bays left…
Amazon – STBV5000100. Get some guitar picks to open the external enclosure without scratching it, takes like 1-3 minutes, plug into computer, convert to GPT, format, done. I still don’t know why the external hard drives are so much cheaper than the internal drives. Loss leader? Inferior components?
This seems like a cheap
This seems like a cheap wholesome price for such components , i quer also where they came from , i,m trying to expand my storage to usage space internally…
I went from having a 150gb
I went from having a 150gb hard drive in my my main install position , after trouble with excorcising my routines i decided to install a 2tb sata in the same position , this catered for a lot of the process problems i seemed to be having with renders and games.I split the drive using windows to decompartmentalise my machine and joy of joys it worked , like having a finely tuned engine .I am now happy again although i would like to get some larger one drive spaces to advent my back ups.
It seems to me that these
It seems to me that these kinds of drives are best used as the drive for your OS and not used for games and files and such. I have one of the 750gb models and it used to be my only drive. When comparing bootup times between it and our other pc with a regular spindle drive, it was a good bitfaster.
But for games? Unless you play the same 2 or 3 games over and over again, the amount of flash memory on it just doesn’t make a difference. I really think that with the prices of flash memory falling that seagate should have put more on these kinds of drives, at least doubled it to 16gb.
Is there any benefit in using
Is there any benefit in using this SSHD for a data drive, e.g. for storing home videos on a server rig for streaming over wired network?
Does the firmware erase(move
Does the firmware erase(move out) data in the cache that is not used to much in order to make space available? Would this be useful in a dual boot scenario where one os is not used to often thereby freeing up cache space for the primary os?