Intel Z68 Chipset & Smart Response Technology (SSD Caching) Review
by Anand Lal Shimpi on May 11, 2011 2:34 AM ESTThe Downside: Consistency
Initially it's very easy to get excited about Intel's SRT. If you only run a handful of applications, you'll likely get performance similar to that of a standalone SSD without all of the cost and size limitations. Unfortunately, at least when paired with Intel's SSD 311, it doesn't take much to kick some of that data out of the cache.
To put eviction to the test, I ran through three games—Portal 2, Starcraft 2 and World of Warcraft—then I installed the entire Adobe CS5.5 Master Collection, ran five of its applications and tried running Starcraft 2 again. All of Starcraft 2's data had been evicted from the SSD cache resulting in HDD-like performance:
| Starcraft 2 Level Loading—Seagate Barracuda 3TB (Maximize Cache) | |||||
| Load Time | Load Time After App Install/Launch | ||||
| Game Launch | 9.7 seconds | 17.4 seconds | |||
| Level Load | 15.0 seconds | 23.3 seconds | |||
I thought that may have been a bit excessive so I tried another test. This time I used the machine a bit more, browsed the web, did some file copies and scanned for viruses but I didn't install any new applications. Instead I launched five Adobe applications and then ran through all of our game loading tests. The result was a mixed bag with some games clearly being evicted from the cache and others not being touched at all:
| Game Load Comparison | ||||||||
| Intel SSD 311 20GB Cache | Portal 2 (Game Launch) | Portal 2 (Level Load) | Starcraft 2 (Game Launch) | Starcraft 2 (Level Load) | World of Warcraft (Game Launch) | World of Warcraft (Level Load) | ||
| Load Time | 9.9 seconds | 15.1 seconds | 9.7 seconds | 15.0 seconds | 4.5 seconds | 5.8 seconds | ||
| Load Time After Use | 12.1 seconds | 15.1 seconds | 10.1 seconds | 15.3 seconds | 3.6 seconds | 14.0 seconds | ||
Even boot time was affected. For the most part performance didn't fall back down to HDD levels, but it wasn't as snappy as before when I was only running games.
| Boot Time—Seagate Barracuda 3TB (Maximize Cache) | ||||
| Time | ||||
| Boot Time | 32.6 seconds | |||
| Boot Time After Use | 37.3 seconds | |||
| Boot Time Without Cache | 55.5 seconds | |||
Although Intel felt that 20GB was the ideal size to balance price/performance and while SRT is supposed to filter out some IO operations from being cached, it's clear that if you frequently use ~10 applications that you will evict useful data from your cache on a 20GB SSD 311. For lighter usage models with only a few frequently used applications, a 20GB cache should be just fine.
There's also the bigger problem of the initial run of anything taking a long time since the data isn't cached. The best way to illustrate this is a quick comparison of how long it takes to install Adobe's CS5.5 Master Collection:
| Install Adobe CS5.5 Master Collection | ||||
| Time | ||||
| Seagate Barracuda 3TB (No cache) | 13.3 minutes | |||
| Seagate Barracuda 3TB (Maximize Cache) | 13.3 minutes | |||
| OCZ Vertex 3 240GB (6Gbps) | 5.5 minutes | |||
A pure SSD setup is going to give you predictable performance across the board regardless of what you do, whereas Intel's SRT is more useful in improving performance in more limited, repetitive usage models. Admittedly most users probably fall into the latter category.
In my use I've only noticed two reliability issues with Intel's SRT. The first issue was with an early BIOS/driver combination where I rebooted my system (SSD cache was set to maximized) and my bootloader had disappeared. The other issue was a corrupt portion of my Portal 2 install, which only appeared after I disabled by SSD cache. I haven't been able to replicate either issue and I can't say for sure that they are even caused by SRT, but I felt compelled to report them nevertheless. As with any new technology, I'd approach SRT with caution—and lots of backups.
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davidgamer - Wednesday, May 11, 2011 - link
I was wondering if it would still be possible to do a RAID set up with SRT? For example I would probably want to do a RAID 5 set up with 3 3TB drives but also have the cache enabled, not sure if this would work though.hjacobson - Thursday, May 12, 2011 - link
RE: Z68 capable of managing SRT and traditional RAID at the same time?I've looked for an answer to this without success.
I did find out the H67 express chipset can't manage more than one RAID array. I won't be surprised to learn the same for the Z68. Which is to say, your choice: either SRT or traditional RAID, but not both.
Sigh.
jjj - Thursday, May 12, 2011 - link
" I view SRT as more of a good start to a great technology. Now it's just a matter of getting it everywhere."It actually doesn't have much of a future,so ok Marvell first made it's own chip that does this,now Intel put similar tech on Z68 but lets look at what's ahead.As you said NAND prices are coming down and soon enough SSDs will start to get into the mainstream eroding the available market for SRT while at the same time HDD makers will also have much better hybrid drives.All in all SRT is a few years late.
HexiumVII - Thursday, May 12, 2011 - link
What happens if we have an SSD as a boot drive? Would it recognize it as an SSD and only cache the secondary HDD? It would be nice to have that as my boot SSD is only 80GB and my less frequent used progs are in my 2teras. This is also great for upgraders as now you have a use for your last gen SSD drives!Bytown - Thursday, May 12, 2011 - link
A feature of the Z68 is that any SSD can be used, up to 64GB in size. Anandtech does the best SSD reviews I've read, and I was dissapointed to not see some tests with a larger cache drive, especially when there were issues with bumping data off of the 20GB drive.I think that a larger cache drive will be the real life situation for a majority of users. There are some nice deals on 30GB to 64GB drives right now and it would be great to see a review that tries to pinpoint the sweet spot in cache drive size.
irsmurf - Thursday, May 12, 2011 - link
Hopefully my next workstation will have SSD for cache and an HDD for applications storage. This will greatly shorten length of time required to transition to SSD in the workplace. A one drive letter solution is just what was needed for mass adoptation.Its like a supercharger for your hard drive.
GullLars - Thursday, May 12, 2011 - link
This seems like a good usage for old "obsolete" SSDs that you wouldn't use as a boot drive any more. I have a couple of 32GB Mtrons laying around, and while their random write sucks (on par with velociraptor sustained, but not burst) the random read at low QDs is good (10K at QD 1 = 40MB/s). I've been using them as boot drives in older machines running dual cores, but it could be nice to upgrade and use them as cache drives instead.It would be nice to see a lineup of different older low-capacity SSDs (16-64GB) with the same HDDs used here, for a comparison and to see if there's any point in putting a OCZ Core, Core V2, Apex, Vertex (Barefoot), Trancend TS, Mtron Mobi/Pro, Kingston V+, or WD Silicon Drive for caching duty.
Hrel - Thursday, May 12, 2011 - link
I'd like to see if using something like a Vertex 3 at 64GB would make much difference compared to using Intels 20GB SSD. Seems like it should evict almost never; so I'd expect some pretty hefty reliability improvements.marraco - Thursday, May 12, 2011 - link
Is only matter of time until SSD caching is cracked and enabled on any motherboard.ruzveh - Thursday, May 19, 2011 - link
Not so impressive as i would like it to be.