OSX Mountain Lion 10.8 UAS UASP USB Attach SCSI drivers

My blog was one of the first to write about UAS/UASP (USB Attached SCSI) on the Mac OSX platform last summer. I've been writing about it for some time.

I've been getting a lot of Google search query hits on my blog for "Mountain Lion UAS drivers", "OSX USB Attach SCSI", and "OSX UASP drivers."

Well, here is the answer for all those daily search queries in this blog post. If you came here from a search engine, this blog will help you find your answer.

What is UASP? In short.

• Enables storage products to operate much faster by utilizing the faster bandwidth now available with the new Super Speed (USB 3.0) standard
• Reduces the protocol overhead of Bulk-Only-Transport (BOT)
• Supports SATA native command queuing (NCQ)
• Multiple commands are processed in parallel

There is no "drivers" for UAS/UASP. If you have Mountain Lion, the "drivers" will be system kexts located at: /System/Library/Extensions

There are two USB kexts that OSX uses for mass storage:

IOUSBMassStorageClass.kext
IOUSBAttachedSCSI.kext

The first one for standard, traditional Mass Storage BOT (Bulk only transport) and the second for UASP. Even old Macs without USB 3.0 UASP ports will have the IOUSBAttachedSCSI.kext installed. It doesn't mean your Mac has UASP hardware.

To find out if your Mac supports UASP, here is a simple test.

Plug in a USB device. Go to  "About This Mac" > More Info > System Report  and scroll down to "Extensions" under Software.

If you have a BOT (aka regular USB drive) device, the IOUSBMassStorageClass will load up. A simple test is to plug in an older USB 2.0 stick/drive. See screenshot below.

Now, quit the "About Mac / System Information applet" and plug in your USB 3.0/UASP drive. Reload the About This Mac and repeat the previous step.

If  the following "IOUSBAttachSCSI" shows up, your Mac takes advantage of the faster SCSI USB like protocols, UAS.

I've notice that if you plug your device into a USB hub, it does not load up the UASP kext.  So take note. Even with some USB 3.0 hubs, the device will drop down to BOT Mass storage. This will be interesting to take note in the future.

Simple. Now, you don't have to Google around anymore for OSX "UASP" drivers. It is all there in Mountain Lion. The kext will load on-demand as your plug in your UAS/UASP USB 3.0 Super-speed devices.

Now, if you want to see UASP in action, here is a review of a UASP device in OSX: the Blac X 5G and a youtube video of it's speed below.

BlacX 5G USB 3.0 Update. Fastest USB 3.0 on a Mac

A few months back, I blogged about the BlacX 5G USB 3.0 dock and it being one of the few USB 3.0-SATA dock device to support UASP (USB Attached SCSI Protocol). UASP is a supercharged version of USB 3.0 with an extra boost of turbo. Anandtech noted that the new 2012 Ivy Bridge Macbooks now supports UASP.

With 10.8.2 update, I decided to follow up by seeing if anything has changed using Samsung 830 SSDs.

Today, I tried USB 3.0 booting from an Samsung 830 SSD and I was floored. 12 second cold boot into Mountain Lion. But most importantly, I was getting Thunderbolt speed in the "real world."

Then I ran some benchmarks.
305 MB/s Write on average and 400 MB/s Read.

Thats right. 300/400 MB/s. I still could not believe it so I booted into a few different installs of Mountain Lion 10.8.2. I even tried another Samsung 830. I ran this test 4-5 times with different configuration to see if there wasn't a fluke.


I discounted BlackMagic's speed test and monitored the Disk I/O the Activity Monitor. As you can see, copying and reading 50GB of tests, you can see it reading 400 MB/second. OK, BlackMagic wasn't acting weird.

I then tried my real world test of copying a 30GB Virtual Image .VMDK file.
A 30 GB ( 29.31 GB VMDK to be exact) took 1.33 seconds to copy.

To do the math. It definitely corroborates the benchmark. According to my calculator, it wrote at 300.56048 MB/second in real time. This is not a synthetic benchmark but what you will actually get in the real world.

After reading all of this and you still don't believe me?
I did a video on my iPhone.

http://www.youtube.com/watch?v=GaHPh5cKmTI

There you have it. This may be the fastest USB 3.0 to SSD adapter setup on a Mac and even PC (unless you have a new rare Gigabyte motherboard with UASP USB 3.0 controllers). These test were done using the Samsung 830 SSDs.

The Blac X 5G is smoking fast with UASP. It appears to have an ASMedia 1051 controller.

OSX Mountain Lion, 2012 Macbook and USB Attached SCSI UASP

Anandtech first reported that the new 2012 Ivy Bridge Macbook Pros support the USB 3.0 Attached SCSI protocol (aka UASP). I decided to test it for a spin and try it out for myself.

You can think of UASP as a supercharged version of USB 3.0. Faster and better bang for the buck (lower CPU utilization).

UASP promises faster transfer speed with SCSI like protocol, eliminating the previous BOT (Bulk-Only Transport) method of USB transfer. Prior, USB was notoriously known for sucking up CPU resources during copies. There is quite a bit overhead with BOT and UASP solves this. In short, USB 3.0 devices with UASP are faster than regular, traditional BOT USB 3.0 implementations.

You need a host and a device that both support the protocol to realize any benefits of UASP.

The only USB3 - SATA dock that I know of that supports UASP is the Thermaltake Blac X 5G which I have in my possession. The dock requires a firmware upgrade to unlock the UASP features.
It is a rather nice dock that is similar to the Voyager Q but only supports USB. You can use 2.5 and 3.5" drives. It also comes with some handy drive covers to keep it clean and tidy looking.

I previously used quad interface  (firewire400/800/esata/usb) NewerTech Voyager Q but I had so many problems that I switched to the Blac X. The Blac X doesn't get much notice in the Mac community and the Voyager Q's popularity is due to the fact OWC sells it as their main SATA dock.

For mid 2012 Macbook Air/Pro/Retina owners, it is now time to look at the Blac X.

My initial impression of the Blac X wasn't that favorable due to the fact it perform rather so-so under Lion (OSX 10.7). It was not giving me the speed improvement compared to using a Seagate USB3.0 to Sata Go-Flex adapter. In fact, I was ready to return it until Mountain Lion was released.

Mountain Lion (OSX 10.8) changed all that. I don't have a reasonable explanation but it is definitely faster. Possibly, Apple had  more resources to optimize their USB 3.0 drivers for Mountain Lion rather than concentrating on Lion. Whatever the reasons, the Blac X 5G's performance under 10.8 is very good.

First, compared to other docks and SATA interfaces I've used, CPU utilization running test and large copies were under 5% versus 7-10% on others. Could this be UASP at work?

My tests consisted of using a Crucial M4 Sata 6 SSD. I tried formatting HFS+, exFAT and FAT32.

My initial tests under Lion was a bit of a disappointment as seen below. 135.5 MB/s reads from a SSD.

With a Go-Flex adapter, I had better performance under Lion

With a 5400 rpm Toshiba Drive (the one that came with my Macbook) and the Blac X perfomed like any other dock. This may be due to the bottleneck of the 5400rpm drive because the using a Go-Flex adapter gave me similar results.

Go Flex adapter with the same 5400 rpm Toshiba.

For platter drives, as I mentioned in my other posts, USB 3 and Firewire 800 are pretty close. It is only with SSDs you see the major benefits of USB 3.

With Mountain Lion now officially released, I decided to do the tests again.

Here it is with the Crucial M4 again. As you can see, it is a big improvement. 268.2 MB/s reads and 179 MB/s writes via USB 3. The Blac X 5G is definitely now worth the investment.

Compared to the Go-Flex,there is little change between Lion and Mountain Lion. As you can see the, the Blac X is definitely much faster now under Mountain Lion.

There you have it. Mountain Lion brings in some new speed optimizations for Macs with USB 3.0.

Update 2012-10-07.

It seems 10.8.2, it is even faster. Read my update with video here:

http://fortysomethinggeek.blogspot.com/2012/10/blacx-5g-usb-30-update-fastest-usb-30.html