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Seagate's New SSHD Hybrids Have Dual-Mode Flash Caches
crookedvulture writes "Seagate's has revealed its next-generation hybrid drives, and for the first time, there's a 3.5" desktop model in the mix. The new family of so-called SSHDs includes standard and slim notebook variants with 500GB and 1TB capacities, plus 1TB and 2TB desktop versions. All of them combine mechanical platters with 8GB of NAND in a dual-mode SLC/MLC configuration. The SLC component is largely reserved to cache host writes, while the MLC portion is filled with frequently accessed data to speed read performance. Despite MLC NAND's lower write endurance, Seagate claims the SSHDs have more than enough headroom to last at least five years with typical client workloads. More impressively, the mobile SSHDs are supposed to be faster than the old Momentus XT hybrid even though they have slower 5,400-RPM spindle speeds. The mobile models are slated to start selling shortly at $79 for 500GB and $99 for 1TB, while the 1TB and 2TB desktop flavors are due in late April for $99 and $149, respectively. Unlike other NAND caching solutions, Seagate's tech requires no software or drivers, making it compatible with any OS."
Why is this better than having 1/2 boot SSDs and an HDD RAID for storage?
Ah crap! I just bought the Momentus XT 750 version a couple weeks ago. I'm pleased with it. Not as fast as SS drive, but roomier and cheaper. But crap, if I'd just waited ...
Then again, I was expecting the next version to have 16 or 32 gig of flash. And I did get a 7200 rpm drive. Handy for some of the huge files I process.
The world is made by those who show up for the job.
Unlike other NAND caching solutions, Seagate's tech requires no software or drivers, making it compatible with any OS."
Yes, which means the drive is basically stupid-caching everything. There's a reason you want block-level access to devices. It's called performance. What's the point in having a SSD hung on the side that can't be independently accessed? Stupid-caching means it can't predict what I want next, and since it looks just like any other HDD, the OS' own cache optimization routines are going to be totally fucked because there's no way for the device to talk to the OS intelligently... or vice versa.
Fail.
#fuckbeta #iamslashdot #dicemustdie
Seagate claims the SSHDs have more than enough headroom to last at least five years with typical client workloads.
The typical client workload is that user powers on own computer, windows starts and then user opens WWW browser and browse web and then does some files with MS Office and turns off the computer.
How about those typical client workloads where almost every day is needed to manage 16-30 gigabytes of new data, what gets edited and copied multiple times?
My system has 8GB ram, most of it is used by the OS to cache files. Really all that SSD's do, is to speed up the start up times. Once the machine is running the common files are all in RAM anyway.
Writes are not done synchronously on most OS's these days. The write sits in RAM waiting to be flushed when the disk catches up.
Really the only thing you're speeding up is old disk based databases larger than your RAM size, and your first boot time. And 8GB of NAND FLash isn't enough to speed up the large databases.
Note also Windows has long preloaded commonly used files into the Ram cache making this NAND less than useful.
IMHO, if disk makers want to do anything, it should be to concentrate on integrity of data.
Considering Newegg has 3 TB for $140 on sales, and these look like they cost about 2x too much, AND given my personal experiences with Seagate 500 gb drives of all kinds. No thanks. I think I'll wait for the 1 TB flash drives Kingston supposedly demoed at CES already instead.
For a mere 8GB acting as cache in the drive, I'd rather spend $30 on RAM and let the OS use it for buffering/caching data (which Linux at least will do pretty intelligently for me even without changing /proc/sys/kernel/whatever).
I love my SSD but that's way more than 8GB. As an extra bonus, the RAM can be allocated as necessary, is faster, and there are no write/erase issues with it.
Now, come up with say 2TB on platters and 128GB flash and we're talking a different proposition.
8GB might be sufficient for those who care about how quickly they boot up (assuming the bulk of the kernel etc ends up in the flash cache and stays there until shutdown) but I only reboot about once a month at most.
Given the relative ease of failure for flash memory compared to mechanical, the Momentus XT 7200's will end up winning on the long term.
Twitter supports and protects racists - by smearing their critics with the "Hate Speech" label.
8GB might be sufficient for those who care about how quickly they boot up (assuming the bulk of the kernel etc ends up in the flash cache and stays there until shutdown) but I only reboot about once a month at most.
you can buy a USB 3.0 stick and put your OS on it if you care about it that much. 8GB is nothing. Without any drivers so the OS can be aware, it's basically an HDD with one duct taped to it anyway...
#fuckbeta #iamslashdot #dicemustdie
Flash makes little difference to read performance, but can make a huge different to write speeds. RAM, being non-volatile, means that if an application calls fsync, you block until all of the data has been flushed to the disk. With a flash write cache, you can buffer a load of writes and return almost immediately (writes into flash can easily go at 100+MB/s) and then write them out to disk when it is idle or less loaded.
I am TheRaven on Soylent News
Flash makes little difference to read performance, but can make a huge different to write speeds.
That depends on what you're reading. It makes a huge difference if it's not one large file read sequentially.
Will these drives finally break the 5.9 barrier? From what I've heard, the old XT's didn't.
I have the first gen XT and I can say is that these things are everything they're cracked up to be. If you're not buying an SSD then you should be getting one of these. Generally if you strip away the SSD portion you're still left with one of the best mechanical drives on the market, but the SSD portion really and truly does make a solid and positive difference in everyday computing life.
There is zero gain to be had from sticking those files on a SSD, the disk is never accessed.
Once your RAM file cache is more than the files you load, file access is essential zero seek and 2GB+ reads and writes. Don't forget here we're talking about RAM. The disk is NEVER touched once its cached, there's no possibility for a disk that isn't being accessed to speed up a read from the RAM cache, and no benefit from speeding up a deferred write that's done in the background.
The trick is to have more RAM than you need to hold the files you access. So for me (Firefox, Open Office, Eclipse), the RAM file cache fits in 2GB of RAM, and the disk light never blinks except on a save. I still have some 4 GB of ram cache space unused on my system.
But worse still, this isn't even an SSD. It's an SSD cache on a hard disk, and a very small one at that.
Disk storage contains filesystem metadata. Sooner or later writes *have* to go to disk regardless of how much RAM you have. Flash can accelerate that. RAM and flash are not interchangeable and 8GB can be enough for some applications.
"You don't know how writes in a filesystem work"
Yes I do, if you care to explain why you believe that, I can point out where you're wrong, or accept your explanation. But I do know how the file cache on Windows works.
"If your "disk light never blinks" you aren't using your computer."
Yes I do, I compile large programs, and edit video. But realistically, editing a 100MB video with 6GB of ram cache, the file I copy to disk from SD card to the disk never leaves the RAM.
I suspect GP didn't put enough RAM on his PC. That's the worst thing you can possibly do, have loads of RAM used for a file cache but *not* quite enough. Then the disk spins down, and the first time it needs a file, it has to spin up again. Stick more RAM in if that's happening. Unfortunately with this product you can't stick in more SSD, so you'll get the disk spin up effect if 8GB SSD isn't enough.
I see this as an attempt from Seagate to gain marketshare from the technically clueless. The hybrid name was not working so they have to rename it SSHD, hoping that a lot of people will not see that H in the middle of the drive type. I see a lot of purchases by clueless people hearing the tech crowd talk about SSD. They will be misled by Seagate and purchase this device, and after running the device will wonder what all the fuss was about with Solid State Drives.
Granted they're faster than most peoples 5400rpm drive running in their laptops, but these are in no way comparable to a second gen SSD. I see a lot of tech calls from the clueless asking for installing an SSD, and I have to be the bearer of bad news that they were misled by Seagate that this is not an SSD, it is a SSHD (aka still a hard drive with platters).
I really wish that drives could be optionally set (via a jumper?) to allow the OS to see these built-in SSDs, and not have them hidden behind the firmware.
There are more and more systems out there can configured to intelligently use flash: Linux has Bcache; FreeBSD, Solaris, and Mac OS X have ZFS. I'd love to be able to set up a home server to use these drivers for read (L2ARC) and write (ZIL) acceleration, and I'm sure a lot of OEMs would love to have distributed/striped flash in their storage offerings.
The bulk volume of spinning rust, and the IOps of flash, all in one convenient package.
If anyone at Seagate (or any other hard drive vendor) is listening: if you do this you will gain an immediate advantage over your competitors. (Until they copy you of course.)
Besides the write performance Raven noted, the flash block cache has two additional advantages over more RAM: depending on your workload, it's entirely possible for a working set to take up most of the 16GB limit for many systems these days, and all the RAM in the world doesn't help you on system startup. I have the second-gen XT, and there's a noticeable difference in boot/launch times the second and third time a version is loaded over the first.
Seagate Momentus XT 750GB in 2.5 inch form factor - perfect for an older laptop with a dedicated graphics card intended for both early generation games, temporary torrent storage and speed.
I've been doing the following with Ramdisks/Ramdrives below, & since 1992 or so, 1st by using separate HardDisks (slower seek/access by FAR)!
Then, later applying Software-Based Ramdrives to database work with EEC Systems/SuperSpeed.com on paid contract (which did me VERY WELL @ both Windows IT Pro magazine in reviews, & also MS TechEd 2000-2002 in its hardest category: SQLServer Performance Enhancement & SuperSpeed.com too - since I improved their wares efficacy by up to 40% via programmatic control & tuning programs for them) - which, only the past few years now it seems, OTHERS are finally "latching onto" for performance purposes in database work in industrial environs!
Then using software ramdisks (even one I wrote up based off the MS DDK template -> http://www.google.com/search?hl=en&output=search&sclient=psy-ab&q=%22APK+RamDisk%22&btnG=Submit&gbv=1&sei=Ak43UduzLYbk8gSauYCIDA to do so (per the list below on how I apply them)
&
Now FINALLY using RamDisks/RamDrives in hardware:
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A.) 2000-2005 using the CENATEK "RocketDrive" 2gb PC-133 SDRAM based on a PCI 2.2 bus
B.) 2005-present using the Gigabyte IRAM 4gb DDR2-RAM based on a PCI Express bus
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Doing SOMETHING sort-of along the lines of what's being done in the "hybrid" caching scene, & that's using equipment/hardware like I do in the following ways:
For example - I do it this way (along with other things, & on a "TRUE SSD" (not based on FLASH ram & it's performance degrading life expectancy lessening "ways")):
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1.) I move files around to different drives (1 being what I call a "TRUE SSD", that uses DDR RAM, the Gigabyte IRAM 4gb PCI-e 8x slot based SATA 150gb/sec. solidstate drive I have)
2.) A Promise Ex-8350 PCI-e 8x slot based 128mb ECC RAM Raid 6 capable Caching Controller (that controls 2 10,000 rpm Western Digital 16mb buffered "Velociraptor" HDDs)
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(Both supplementing the existing caches noted above @ the Operating System filesystem level, AND, the block device level)
I also supplement my 10,000 rpm SATA II disks using a Promise Ex-8350 128mb ECC memory Caching Controller (keep it OFF hdd's as much as possible, & in RAM instead is the idea/game here).
I move the following things off of my WD Velociraptor 10,000 rpm 8mb buffered (which also lessens physical head movement on disks & THIS is where I am going to make it even FASTER, read on & reduces fragmentation as well in the same stroke - "BONUS"):
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A.) Pagefile.sys
B.) OS & Application level logging (EventLogs + App Logging)
C.) ALL WebBrowser caches, histories, sessions & browsers too
D.) Print Spooling
E.) %Temp% ops (OS & user level temp ops)
F.) %Tmp% ops (OS & user level temp ops)
G.) %Comspec% (command interpreter location)
H.) I also place my custom hosts file onto it, via redirecting WHERE it's referenced by the OS, here in the registry (for performance AND security):
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HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\Tcpip\Parameters
And the "DataBasePath" parameter there...
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Which also acts more-or-less, like a *NIX shadow password system also!
(That's good, vs. any malware that *might* attempt to 'mess with it since the original residing in %WinDir%\system32\drivers\etc is pretty much only a 'decoy' @ that point, lol!)
However, modern Windows uses UAC to protect it, & I also apply read-only rights to it to supplement that, & my hosts file import/deduplicate/favorites hardcoder mgt. system I wrote -> http://www.start64.com/index.php?option=com_content&id=5851:apk-hosts-file-engine-64bit-version&It
But pay attention to the price.
Flash is roughly $1/GB. 8GB of flash costs about $8, which is in line with the ~$10 price increase of an SSHD over a similar pure hard drive. At 128GB, though, you're spending as much or more on just the flash than the SSHDs here cost.
Not to mention the physical size. 128GB SSDs take up quite a bit of the space available in a 2.5" disk. You aren't likely to see a 2TB hard drive and a 128GB SSD in a single enclosure anytime soon, simply because that won't fit into a single drive bay.
Nobody ever said these weren't fast or cheap. What they did say was massive data corruption, nonstop blue screening, and completely inconsistent performance. Also, if the drives lose power, you're screwed even if it was idle because it wasn't idle. It was moving data between the cache and main storage based on usage counts. Those constant writes, by the way, kill the flash memory very quickly. Plus, you can have a mechanical failure. Forget any kind of data recovery too. These are a terrible idea. RAID arrays of SSDs for large storage of a 120GB boot drive with a 1TB secondary are both very cost effective solutions and are both much safer. 4x60GB Intel 330 drives in raid5 take up like 15 watts, cost under $300, and run at around 1GB/s read speed in real world tests. Even RAID0 2x60GB ones I've tested at 800MB/s read. 3x120GB drives in RAID5 is sometimes even cheaper and almost as fast.
why not have a 2-4GB ram disk with slower / older ram on some kind of card / sata device? Just use it for temp stuff and it does not need a battery back up.
Because it's faster and cheaper to just chuck more RAM in the machine. And you get about the same effect by using a USB stick for readyboost on windows or swap+logs on Linux.
Your challenge fits this tune "Rev on the Redline" -> http://www.youtube.com/watch?v=IAZMBVzTYrw
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"2 in a row: Everybody knows, at the greenlight - You REV IT ON THE REDLINE! Been waitin' all week (to get my wheels on the street), get my hands on the wheel, & slide down in the seat! She's wearin' new colors (& runnin' pretty good) - I got 400 horses tucked under the hood! But there's no need to panic: It's under control. We're aerodynamic & ready-to-roll!"
---
Good luck (you won't need it - compiles speed up off SSD or ramdisks in software (especially here when the data fits inside the L1/L2 caches in the CPU & running from SYSTEM RAM (which is faster than SSD's can be)))...
APK
P.S.=> Lastly - Some ideas for you, you *MAY* like -> http://hardware.slashdot.org/comments.pl?sid=3519325&cid=43092067 that will gain you EVEN MORE performance (in surprising ways - some obvious, some more 'subtle', but there nonetheless...)...
... apk
There is only your cheapness. Drives are the slowest part of your gear. Scrimping a few dollars to make them sort of faster is more expensive than spending all the money you need to make them as fast and as reliable as possible.
"Medication" -> http://www.youtube.com/watch?v=THE_hhk1Gzc&feature=related @ position 1:05 on the YouTube player control!
How's that suit you?
After all - The results are the same here, myself, vs. yourself (& your off-topic trolling b.s.)... & quoting him again here, since it fits:
"That's what it DOES Karl - it puts me 50 moves ahead of you!" @ position 2:11 on the YouTube player control (good film - I suggest you see it in fact).
That, & my use of SSD's does so, easily as well, by NOT having to MOVE hdd read/write heads either... (easily & @ THE VERY LEAST, it keeps me "50 moves ahead of you", all the time - especially avoiding disk head moves!)
APK
P.S.=> I suppose that the "meds" I am on (though I am not literally on ANY here) simply would be "PURE SPEED"!
All, per this post to another making a challenge to others here in this thread -> http://hardware.slashdot.org/comments.pl?sid=3519325&cid=43092869 & the tune I quoted in it!
Here's another that fits perfectly from that same excellent Foreigner tune:
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"Don't think I'll ever learn to SLOW DOWN... you'll still be here, & I'LL BE GONE!" - Foreigner "Rev on the Redline"
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(Especially since that tune's ALL about performance... & speed!)
However - it's NOT "pharmaceutically induced speed" on MY end, it's technology based in computing... In my using solid-state disks or ramdrives softwares for performance gains here, for ages!
( &, as to my using Mr. Morra from LIMITLESS above? Well - I just use that vs. "meds trolls" & their STALE old worn out off-topic trolling crap, like yours, since it fits here (lol))... apk
Including building entire distros from source for embedded stuff. In my experience when compiling stuff the bottleneck is the CPU, not the disk. On the other hand, when trying to dig around in hundreds of megs of git repository it's a pain to wait for a spinning disk.
USB is slower with high CPU overhead and that eats up USB bandwidth that you may need for other USB stuff.
Flash makes little difference to read performance
I totally got my system configured wrong then, because I get ~1,000MB/s reads off my flash with 0.1ms access time (RAID-0), and ~110-160MB/s reads off my HDDs with 9ms access time. Please tell me how to reconfigure my system so that I can get the same performance from my HDDs as I do my SSDs. And before you ask, I also have a hardware RAID of 8 3TB drives, and it still isn't as fast as reading my SSDs.
I have never seen a situation where using a USB device was 'faster' than ANYTHING on a hard drive.
ReadyBoost has never made a USB 2.0 device faster than just pulling the original data off the hard drive.
Its a cute idea, but in practice it fails instantly.
Swap ... on USB? Are you fucking kidding? Do you have any idea how much that would suck absolute ass?
Your hard drive is orders of magnitude faster than your shitty USB device. My iron-oxide disk is at least 10 times faster than the USB3 key plugged into my machine, and thats ignoring my SSD boot drive speeds, which guess what they due to the speed graph?
USB* is slow, even at USB3 speeds its a dumb idea.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
why not have a 2-4GB ram disk with slower / older ram on some kind of card / sata device? Just use it for temp stuff and it does not need a battery back up.
I remember having an ISA card that acted like a RAM disk back when computers had much more serious memory constraints, I think I had it on an 8086, which had a 1MB addressable space limit.
It was incredibly fast, I was using it to hold temporary files to help speed up a sort that wouldn't fit in memory - I think it had 128KB of RAM and it was incredibly fast - well, as fast as an 8 - 16MB/sec ISA bus could be.
But I can't imagine that there's much of a market for this type of accelerator these days since most people that want fast RAM disk performance just add more RAM to their computer and let the operating system manage it - getting a new motherboard with more RAM capacity if needed. I did find this card, which includes a backup battery so it's not just a RAM disk, the contents don't go away when you turn off your computer:
http://www.newegg.com/Product/Product.aspx?Item=N82E16815168001
It probably has lower latency than an SSD, but it acts as a 1.5 Gbit SATA interface, so transfer rate is limited to 150MB/sec.
I've also seen SSDs on a PCIe card, but that's not quite the same.
There's plenty of room in a 3.5 form-factor to included a large amount of NAND in a hard-drive. 2TB + 128GB seems both viable and very desirable.
That depends on what you're reading. It makes a huge difference if it's not one large file read sequentially.
Oh, I see you've compiled a large project at some point.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
8GB isn't enough cache for those of us who want the OS and multiple large applications on the SSD. But 32GB or 64GB of cache might be. I frequently use Xcode, Eclipse, Photoshop, Logic, and another dozen applications on a daily or weekly basis, and if I don't want to wait 30 seconds for Photoshop to start, then I'm still looking at getting a main 128GB SSD and a regular HD and setting up a Fusion drive, or just going all SSD. I somehow doubt 8GB of cache will live up to any expectations I have about loading times compared to the SSD that I'm used to.
Can you access them on port 22 ? ;-)
"iron oxide"? You're old. It's been cobalt based for years now.
Hi, welcome to Slashdot. For future reference, you may be aware of this little thing called 'context'. This means that words written in one post relate to things mentioned in the post that it is a response to. For example, my post was in reply to a post suggesting using more RAM, instead of flash. The context of my comment was that flash [as a cache] won't make a difference to read performance [relative to a disk behind a large RAM cache]. Interpreting it as saying 'an SSD is no faster for reading than a spinning disk' makes you look like you've just failed the Turing Test.
I am TheRaven on Soylent News
I totally got my system configured wrong then, because I get 22GB/s reads off my RAM with 60ns access time (uncached) and ~500MB/s off my SSD... :)
http://hardware.slashdot.org/comments.pl?sid=3519325&cid=43093681
* :)
(That's not ME saying that either, it was someone else - but, I agree with it, to "overcome your objections" on THAT specific note (master file table/mft$ accounting entries)).
APK
P.S.=> There's always more than "1 way to skin a cat", & that one's THAT, for that which you speak of on NTFS-based filesystems on Windows NT-based OS...
... apk
Even IF you disable the pagefile.sys on NTFS... how/why? Exe's page back to themselves is how/why!
(When shuffling data in & out of RAM, such as resources, up out of the original exe off disk, rarely if EVER, back to it (self-modifying exe's are considered a "no-no", but DO exist)).
* :)
APK
P.S.=> It used to be also that you really COULD completely disable paging on Windows NT-based OS, but I don't think you can, completely, on Windows 7 (possibly VISTA too, I never used it or cared to here) - it will force a MINIMUM 16mb pagefile.sys in the root of your OS drive, or temporary one @ least, beneath %WinDir%\system32 iirc, & mainly for the sake of memory dumps analysis @ the very least - however, that material above helps explain WHY You'd see paging too even IF you disable paging for the OS proper itself & using pagefile.sys to do so (exe's do it, via their own filemass on disk)...
... apk
Your hard drive is orders of magnitude faster than your shitty USB device. My iron-oxide disk is at least 10 times faster than the USB3 key plugged into my machine
Congrats, you bought a shitty USB3 key and a decent spinny disk. This is supposed to prove what?
USB* is slow, even at USB3 speeds its a dumb idea.
Stop being obtuse. USB* limits aren't the reason why cheap USB flash keys are slow. They're slow because they're cheap. There's no budget for a fast flash memory controller, or higher grades (read: faster) of flash memory, or enough channels of flash memory to be fast.
If you use a fast flash drive, things are a bit different. I recently constructed a USB3 disk from a $20 off-brand bus-powered USB3-SATA enclosure and a Samsung 840 Pro SSD. It does over 300MB/s read and write, easily twice as fast as any HDD, and that's with a sub-optimal USB software stack (I believe the Linux machine I tested on did not have support for the new UASP mass storage device protocol, which is required to get the best performance out of USB3 disks).
Also, that's 300 MB/s sequential. The real strength of flash storage is random I/O. That was the theory behind ReadyBoost, as a matter of fact. Microsoft's caching algorithm monitors both access frequency and access patterns, and only tries to use the ReadyBoost device to cache data frequently read from the HDD in random order. 7200RPM desktop HDDs are limited to about 100 random I/O ops (IOPs) per second, so even a relatively cheap USB2 stick can help in that department. HDDs are only fast when doing sequential, streaming transfers.
(Cheap USB sticks are really slow at random writes, due to not having enough flash die and/or interface channels. For that reason ReadyBoost also tries to batch writes to the RB device into large sequential chunks. Also, because writes are generally slow on cheap USB sticks, it's only used as a read cache, and data is only copied to it in the background.)
For future reference, being able to write so that you get your meaning across is apparently a skill that you lack. What you wrote could have been interpreted many ways, of which I read to mean one way, while you meant it another. Regardless of the context, and since this is a discussion board, you could have been trying to convey any of a multitudes of thought. I suggest you write your thoughts clearer in the future.
Hi, welcome to Slashdot. For future reference, you are coming across as snarky and a bit of a dick. Which wouldn't be too bad if you had expressed yourself well... but you did not. I had to re-read your post, its parent, and your clarifying reply before I figured out what you meant. While I may be slightly tired from digging through EMC docs today, I would like to think my brain is still largely functional.
SWM seeks new sig for a brief fling
How big is a typical whole hog Windows installation with Office and CS5.5 and several other programs? My wife had one of those 52GB 60GB OCZ drives and it was very tight. A real 64GB drive would be fine. So let's take her 1.5TB WD Caviar Green and tape on a 64GB stick of flash with its own SATA data and power connectors. Now I have one 3.5 inch physical drive in one bay, two data cables, two power cables, and if I mix in an external optical drive, I can build her next machine in an ITX case instead of microATX, and it'll have airflow like a boss for something like a GTX660Ti. Sounds good to me. Otherwise, maybe someday Gigabyte will take their "mSATA slot on the motherboard" idea and apply it to something smaller than ATX.
5400RPM for your 3rd gen Hybrid drives don't make sense. It is opposite to your policy of desktop drives, where you no longer make 5400/5900RPM desktop drive but just 7200RPM drives. This was because you think 5400RPM drives waste time and don't save that much power and you are exactly right.
Why not make the same policy for laptop drives? Power consumption isn't an issue. A 5400RPM vs 7200RPM drive takes less than 1 watt more on average. I know hybrid drives are a bit different but they still benefit from fast mechanicals since it's only 8GB of flash and doesn't cache writes.