Hybrid Hard Drives: Take Two

Thar she blows! Seagate's hybrid ssd/hard disk drive is real!

The new drive family sports 4 GB of NAND flash and 32 MB of DRAM operating in tandem as a cache. It is a 2.5″ model, and since Seagate doesn’t currently produce a drive fatter than 9.5 mm one can assume it is a two-platter model and will work in most laptops. It sports a 3 Gb/s SATA interface with native command queueing (NCQ), nicely up to date but nothing special.

There are three models in the Momentus XT line, all with the same 4 GB/32 MB cache:

Unlike the previous-generation H-HDD drives, the new Seagates have fully-integrated SSD cache featuring speedy SLC chips. The dependence on the host operating system to make caching decisions was one of the things that sunk H-HDDs in the past, but this looks to be an entirely different solution. Seagate looks to have integrated the flash as an extension of the RAM cache and is using the drive’s own logic to determine what to cache and when. This will not only be more-generally applicable (not requiring a special OS) but will likely work better, since on-drive cache management has improved greatly over the years.

Stephen’s Stance

Assuming I’m right about Seagate’s fully-integrated cache architecture, this drive ought to blow away everything else on the market. The Register includes test results showing SSD-like performance for many workloads, yet this drive is half the cost and twice the capacity. It beats the 10k VelociRaptor drive in every test and will absolutely smoke any “normal” 7200 or 5400 rpm laptop drive. Feel free to exclaim “wow!” at this point.

How excited am I? How about this: Although I upgraded it just last month with a 640 GB Toshiba hard disk drive, I want a Momentus XT in my MacBook Pro. I’d rather have one of these than a straight SSD, considering the mix of performance, capacity, and price. Maybe I can move the Toshiba into an MCE Technologies OptiBay?

I will be watching this release with great interest. Word is that Seagate will officially unveil the drive in a webcast on Wednesday, May 26. I look forward to a flood of performance tests from my favorite consumer sites, and expect it will interest the enterprise guys, too (this means you, Howard!) Could hybrid drives finally be getting real?

© sfoskett for Stephen Foskett, Pack Rat, 2010. | Smoking-Fast Laptops: Seagate Momentus XT Hybrid SSD Disk Drive Confirmed!
This post was categorized as Apple, Enterprise storage, Personal, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

Can you supercharge a Mac Mini?

Last week I reported my progress upgrading my Mac Mini’s RAM and hard drive to extract much more performance out of Apple’s little desktop. And indeed, adding a 7200 rpm high-performance laptop hard drive did make a noticeable difference in system responsiveness.

But a question came in via email asking, will Western Digital’s killer 10,000 rpm VelociRaptor SATA drive work in the Mac Mini? So inspired, I set out to find out just how far one can push a Mac Mini’s performance!

Pillars of Performance

As I noted in my last update, there are four keys to desktop system performance: CPU, RAM, storage, and graphics. The Mac Mini’s CPU is soldered in place and its graphics are integrated into the system chipset, so neither are upgradable. The best one can do on the CPU side is to order a built-to-order 2.26 GHz Mac Mini from Apple, adding $150 to the base Mac Mini price of $599.

Base Mac Mini: $599

2.26 GHz CPU upgrade: $150

Running total: $749

PC hackers commonly upgrade their systems’ performance by tweaking the system BIOS to overclock the CPU, memory, and system bus. But you can’t overclock a Mac Mini, or at least I haven’t found the secret yet.

More RAM always helps, but the Mini won’t accept more than 4 GB 8 GB of RAM. The graphics can also be improved slightly by installing more than 1 GB of RAM because the system will then use 256 MB of RAM as a frame buffer instead of 128 MB. Since we’re going to be opening the system anyway, we can save some money by upgrading the RAM ourselves. The Mac Mini uses 204-pin DDR3 SO-DIMMs rated at PC3-8500 (1066 MHz). A nice 4 GB matched set can be purchased from Amazon.com for $60.

4 GB RAM upgrade: $66

Running total: $815

Your Apple Mac Mini is now maximally configured, with the exception of storage.

Update: The 2009 Mac Minis can now accept 8 GB of RAM!

Killer Storage

The only remaining upgrade is storage. And here, the Mac Mini is amazingly adaptable. About 2/3 of the vertical space covered by that aluminum and plastic exterior consists of a black plastic cage containing the DVD SuperDrive, hard disk drive, and cooling fan and serving as a support for the BlueTooth and 802.11 wireless antennas. This is your target.

The Mac Mini’s storage subsystem is up to date, with two SATA channels supporting 3 Gbit speed and advanced capabilities like native command queueing (NCQ) even though the stock Mini’s hard drive lacks these features.

The hard drive sits in a cradle immediately under the optical drive, face-up in an open cavity over the motherboard. Although it ships with a slim 9.5 mm high hard disk, my ruler says that the Mac Mini cradle can accept a 12.5 mm z-height disk. This is interesting from a capacity standpoint, since some higher-GB drives are 12.5 mm 3-platter units, including the popular TravelStar 5k500 drive from Hitachi.

However, the Mini was designed to have an air gap between the hard disk and DVD drive, and a 12.5 mm drive will press against the optical unit, potentially causing heat problems. And a larger 2.5″ drive will not fit, including the 15 mm mechanism from the Western Digital VelociRaptor.

Therefore, any crazy disk drive dreams that also include leaving the Mini and its DVD drive in the original case are right out. All is not lost, however! Apple kindly included the MacBook Air’s Remote Disc support, so the Mini doesn’t need a DVD drive at all if you happen to have another Mac or PC handy. Removing the SuperDrive leaves room for up to two 2.5″ hard disks!

Without the SuperDrive in the way, a 2.5″ Western Digital VelociRaptor hard disk drive should fit just fine. Although it ships with a massive heat sink, the VelociRaptor isn’t as power-hungry or hot as you might imagine. It might be a good idea to apply some cooling fins or add an extra fan, but I’m betting the Mini wouldn’t have any trouble driving this 10,000 rpm drive once the SuperDrive is removed. So the WD VelociRaptor is a serious option for the Mac Mini.

Another killer performance option is a RAID-0 set of internal SATA drives. Although the Mini’s second SATA channel (normally used for the DVD drive) does not have the proper connectors or mounting supports for a hard disk drive, iFixit sells a DIY kit to connect a second hard drive. This kit, which includes two 500 GB 5400 rpm hard drives, sells for about what a single 300 GB VelociRaptor costs, and should provide similar performance using RAID-0 striping.

WD 300 GB VelociRaptor hard disk or iFixit dual-500 GB kit: $250

Running total: $1,065

Conclusion

So there you have it! For just over $1,000, you can have the baddest Apple Mac Mini possible. But for quite a bit less, I suspect that a 2.0 GHz/4 GB/7200 rpm disk combo would be nearly as fast.

One more thing: If you decide to use RAID-0 on your internal drives, you must use Time Machine to protect your data! A stripe set of disk drives poorly mounted in a tiny chassis without a properly-engineered cooling or power system is a recipe for disaster. Your disks will fail, and your data will be lost!

Note: Some of these links include affiliate codes that help pay for this blog. For example, buying an Amazon Kindle with this link sends a few bucks my way! But I don't write this blog to make money, and am happy to link to sites and stores that don't pay anything. I like Amazon and buy tons from them, but you're free to buy whatever and wherever you want.

© sfoskett for Stephen Foskett, Pack Rat, 2009. | How Far Can You Push a Mac Mini?
This post was categorized as Apple, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.

While swapping out disk drives (first to upgrade the internal drive in my MacBook Pro and later to give Time Machine more room), I took some quick performance snapshots with xbench and showed that, depending on I/O type, FireWire can be almost twice as fast as USB, but neither really holds a candle to SATA.

I also took the opportunity to compare the highly-integrated USB 2.0 controller in my Maxtor OneTouch 4 Mini with the much more complicated FireWire/USB combo found in the Verbatim SmartDisk, as well as the performance of three popular notebook hard disk models.

This post is part of my series focused on PC/Mac Integration.

• Vista, OS X Boot Time Compared
• Quick and Easy Bluetooth Sharing Between PC and Mac
• Yes, FireWire is Faster Than USB
• How to Keep an IOGear KVM from Dimming Your Mac's Screen
• Command and Control: The Clash of Keyboards

Test Setup

I’ll be the first to admit that this wasn’t the most scientific test ever.  I just happened to have three hard drives, two external drive chassis, and one notebook computer, and whipped off a quick xbench test with each of the (many) permutations of these I happened upon.

First, the drives:

1. My MacBook Pro (late 2007) came with a 120 GB Fujitsu MH2120BH drive built in.  This MHY2 series drive is from Fujitsu’s previous generation and was their first with perpendicular recording.
2. I replaced this with a 320 GB Western Digital WD3200BEVT drive sourced from a Verbatim SmartDisk FireWire/USB portable enclosure.  This is the latest Scorpio Blue model from Western Digital and incorporates all their bells and whistles, including native command queueing (NCQ), though it’s not the fastest portable disk they make.
3. After running out of space for Time Machine, I swapped the Fujitsu out for a 160 GB Seagate ST9160821AS drive sourced from a Maxtor OneTouch 4 Mini USB enclosure.  This is also a previous-generation (5400.3) drive and lacks NCQ.

Now, the enclosures:

1. In this corner, we have Verbatim’s SmartDisk portable FireWire/USB enclosure, which originally housed the impressive WD drive.  It’s powered by a mighty collection of electronics, including an Oxford Semiconductor OXUF934SSA controller and some impressive capacitors.
2. In the other corner, we have Maxtor’s OneTouch 4 Mini USB enclosure, which has the most compact integrated interface I’ve ever seen – a single Initio INIC-1605L.

As you can see, the test was seriously flawed.  The drives aren’t comparable, and neither are the controllers. I only ran the test once, I changed the content of the drives between tests, and I didn’t even try every possible combination.  Will this stop me from reporting the results?  No!

USB vs. FireWire

First up, let’s compare the performance of USB 2.0 and FireWire S400.  Rated at 480 megabits per second, USB is supposed to win, but experts agree that it won’t. For example, in Tom’s Hardware tests, every FireWire drive outperforms every USB drive, and that’s a fact.  Despite the limitations of my test, my results bear this out.

Let’s set the stage by comparing the performance of the two interfaces on the Verbatim enclosure to the internal SATA connection in the MacBook Pro.  We’ll use sequential performance numbers only, since random I/O is limited by the seek time of the disk drives.

As we can see, FireWire outperformed USB in every test, and was able to match SATA when it came to sequential reads of 4K.  FireWire S400 was anywhere from 8% to 45% faster than USB 2.0 in my tests, and a difference of this magnitude should be somewhat noticeable to the user.  Note that Apple’s (or Oxford’s) implementation of the USB and FireWire hardware might account for some of this difference.

USB vs. USB

Let’s turn now to a comparison of the USB 2.0 performance of the Verbatim/Oxford enclosure and the Maxtor/Initio alternative. I’ve always suspected that some chipsets were better than others, and I was right! Maxtor is 3% to 8% slower than Verbatim using the same drives.  This should only magnify the differences between FireWire and USB illustrated above!

Drive Against Drive

Finally, let’s see how the disk drives themselves perform.  There are two core considerations: Maximum throughput and seek time.  Larger drives tend to excel at throughput, but seek time (the core component of I/O latency) is more of a black art, with both spindle speed and disk density playing a part.

To compare seek time, we use the random I/O performance of the three drives.  We will normalize against the maximum result in each test to magnify the differences and hide the fact that random 4K I/O is really really slow compared to 256K or sequential access.

We can see here that the drives are fairly well-matched at random reads, meaning that their head movement and tracking performance is about equal, as is their rated spindle speed.  But writes show more pronounced differences, with the Seagate unit quite a bit slower than the others.

One item really stands out:  The WD’s ace performance with tiny random writes.  I’d suggest this is due to the benefits of native command queueing (NCQ), which is present in this drive and not in the others.  It looks like NCQ really does provide noticeable benefits in random I/O!

Finally, let’s think in absolute terms – just how fast are these drives? I only tested the Fujitsu and Western Digital with a SATA connection, but these drives peaked at just under 50 megabytes per second and nearly 57 megabytes per second, respectively.  This performance was maintained on large sequential accesses for both read and write operations.  These are respectable numbers, to say the least:  Half-duplex FireWire S400 should top out at 49 MB/s!  So this chipset and controller must implement the asynchronous streaming feature of 1394a to bump up performance to near-SATA levels.  Awesome!

Although I did not test the Seagate over SATA, all three drives turned in similar large sequential I/O scores on the FireWire interface, which suggests that it would be right up there in streaming performance, at least the equal of the Fujitsu.

In Conclusion

Let me sum up my findings:

• FireWire S400 is faster than USB 2.0 in nearly every respect, and sometimes much faster
• FireWire S400 can even approach SATA when streaming data, but the latter is much faster when it comes to lots of I/O requests
• Different USB controllers can affect all areas of performance
• Native command queueing (NCQ) seems to speed up small random writes by a respectable 2x at least
• Modern-ish notebook drives are wicked fast – every test beats anything I ever saw on my old desktops and laptops

© sfoskett for Stephen Foskett, Pack Rat, 2008. | Yes, FireWire is Faster Than USB
This post was categorized as Apple, Terabyte home. Each of my categories has its own feed if you'd like to filter out or focus on posts like this.