|Samsung 830 Series 512GB SSD|
in GoFlex case
As some Thunderbolt devices are available now and the 512 GB SSD's are a lot cheaper then a year ago (and still expensive), I thought it is time to try Thunderbolt with external SSD, to have a fast
|Seagate GoFlex portable TB Adapter|
|Seagate TB desktop Adapter|
What is Thunderbolt?
If you do not know what Thunderbolt is, read here http://en.wikipedia.org/wiki/Thunderbolt_(interface) and www.intel.com/technology/io/thunderbolt/index.htm and for available Thunderbolt devices you find reports on this link http://thunderboltreviews.com/ Thunderbolt is a development by Intel, and Apple supplied the mini Displayport connector to be used for Thunderbolt connections and Apple had the right to use Thunderbolt for the first year exclusively. But now the number of motherboards for PC's with Thunderbolt ports is daily increasing, and not only a Mac technology anymore, see this page for devices and PC motherboards https://thunderbolttechnology.net/news/press
Do NOT see the Thunderbolt I/F as a replacement for USB3, it is a external extension of the PCIe Bus and Displayport, this means a PCIe chipset or card can be used in a external Thunderbolt box with full speed. As the Thunderbolt link has NO connection to USB devices or USB controller on the motherboard, you need a PCIe USB controller to offer USB2 or USB3 ports on a external Thunderbolt box. So it could replace a USB3 link (when proper implemented), but it is a lot more versatile and can be used as single cable to a docking station with multiple different ports (like the Appel Thunderbolt Display or the Belkin Thunderbolt docking station)
As usual, first the disclaimer:
- You are fully responsible for your modifications
- Any modifications may damage your products
- You loose the warranty on all products, when the products are used in a way they are not intended to be used, (like adding non Seagate HD to adapter, using a SATA extension cable etc)
- You loose the warranty when opening the devices
- The devices loose the FCC, EMI/EMC certification when used different then intended (using a SATA extension without shielding increases the EMI/EMC)
- My results may differ from your results
- This description is only for educational purpose
- I am not affiliated to any company mentioned in this blog
- I do NOT have any insider knowledge of Thunderbolt technology, Apple or Intel
- All trademarks mentioned in this blog are owned by their respective owners
- Apple MBP 17" 2010 with 16GB RAM, Apple 512GB SSD and OCZ Octane 512Gb SSD in caddy as replacement of super drive
- Some Seagate GoFlex disks with USB3 (1.5TB, 500GB) http://www.cyberport.at/apple-und-zubehoer/festplatten-ssd-nas/externe-festplatten/3514-22Z/seagate-freeagent-goflex-usb3-0-1-5tb-2-5zoll-schwarz.html
- Black Magic Speed test http://itunes.apple.com/at/app/blackmagic-disk-speed-test/id425264550?mt=12
- Path Finder http://cocoatech.com/pathfinder/
- iPad2 with oscilloscope adapter, Oscium IMSO-104 http://www.oscium.com/products/mixed-signal-oscilloscope-imso-104
- Multimeter Benning MM P3 http://www.conrad.at/ce/de/product/122730/Benning-MM-P3-DMM
- Seagate Thunderbolt Desktop Adapter http://store.apple.com/at/product/H8582VC/A/seagate-freeagent-goflex-thunderbolt-adapter-for-desktop-hard-drives
- Seagate Thunderbolt GoFlex Adapter http://store.apple.com/at/product/H8581VC/A/seagate-freeagent-goflex-thunderbolt-adapter-for-portable-hard-drives
- Apple Thunderbolt 2 m cable http://store.apple.com/us/product/MC913ZM/A?fnode=MTY1NDA3Ng
- 2x Elgato Thunderbolt 50 cm cable http://www.cyberport.at/apple-und-zubehoer/kabel-usv-zubehoer/kabel/kabel---thunderbolt/4B09-003/elgato-thunderbolt-kabel-0-5m.html
- Samsung 830 Series 512Gb SSD http://www.cyberport.at/apple-und-zubehoer/festplatten-ssd-nas/ssd-solid-state-disk/3306-00Z/samsung-ssd-830-series-512gb-2-5zoll-mlc-sata600---basic.html
- GoFlex 500GB disk red with USB3 adapter http://www.cyberport.at/apple-und-zubehoer/festplatten-ssd-nas/externe-festplatten/3514-231/seagate-freeagent-goflex-usb3-0-500gb-2-5zoll-rot.html
- cheap empty USB2 case
|Samsung 830 Series 512GB SSD in GoFlex case|
As with a lot of plans, it did not work as imagined, the plan needed some modifications. As I found out, after buying all the pieces, the Seagate GoFlex disks do not fit on the Seagate Thunderbolt desktop adapter, because the SATA connector on the GoFlex case is a couple of Millimeters (about 1/4") inside the case and the Desktop adapter has only a short SATA connector and so does not go deep enough in the case to make connection. Read further down about the dis-connects and the resolution of the issue with Seagate GoFlex portable Thunderbolt adapter when connected directly to MBP.
- 20cm (8") long SATA extension cable like this one http://www.conrad.at/ce/de/product/975534/SATA-KOMBI-VERLAeNGERUNGSKABEL-20CM-BULK
Now the first test, connected the Samsung SSD with the SATA extension to the Seagate desktop adapter, connect the external power supply to the TB adapter and to power and then connect the Apple TB cable to my already booted MBP. Voila ! few second later the SSD appears on the desktop. Now starting the Black Magic Speed test, select the TB-SSD, set test size to 5GB and hit the start button.
About 328 MB write and 365 MB read speed.....not bad for a external disk! Copied multiple times 41 Gb vmdk file from my W7-VM from internal OCZ SSD (slower then my new external SSD) with 225 MB speed to external SSD, a couple of times.....all works fine.
|Seagate TB desktop adapter with Samsung 830 series 512GB SSD|
Now the next test, standard 1.5TB GoFlex disk on the Seagate TB Desk adapter and daisy chain with 50cm Elgato TB-cable the Seagate TB-GoFlex adapter with the Samsung SSD attached.
|Seagate portable TB adapter as last point in Thunderbolt daisy chain|
|TB portable in daisy chain after desktop adapter|
Also the standard 1.5TB GoFlex disks works fine on the desktop adapter when used with the SATA extension, but a lot slower.
Thermal Issues with standard configuration
The Seagate TB portable GoFlex adapter get's really hot after a short time. Seems to be a bad design decision to have the hot TB adapter below the disk, as the disk will be heated up even more. With a SSD attached, you can lay the disk head down to improve the thermal situation, but when you use a standard rotational GoFlex disk you can NOT lay the disk down, as a rotational disk shall never be operated head down as the bearing will wear out fast and error correction will kick in very often when the bearing does not work proper. I tested a standard GoFlex 1.5 TB with Acronis backup and SuperFlex Synchronizer software, meaning that the copy process runs maybe multiple hours, the disk gets so hot that you almost can not touch it, this means if you do not want to reduce drastically the live time of the rotational disk you have to use a SATA extension cable that the disk does NOT touch the TB adapter and so reduce the temperature stress.
|GoFlex rotational drive mounted above Seagate TB adapter, as intended by Seagate and the disk gets additional heated up by the TB adapter|
Seagate Thunderbolt GoFlex Adapter with Samsung 512Gb SSD and Elgato cable direct connected to MBP.
|Seagate portable TB adapter with Elgato TB cable direct connected to MBP-pro|
The SSD is shown on the desktop after a couple of seconds, then started Black magic Speed test.....and the SSD disconnects with error message. Sometimes before first speedtest is displayed, sometimes after. When you run the test immediately after you plug in the TB-cable (when TB connectors and Seagate adapter is cold) mostly the first Speed test works, but fails all the time when MBP gets hot around TB-connector, TB-cable connectors get hot and the Seagate portable TB connector gets hot. Don't forget, also the MBP close to the TB connector gets very hot (there is a power controller for the TB port in the MBP, not only in the Seagate adapter.....but we will discuss this later)
|Error with file copy with Path Finder|
|Error with Black Magic Speed Test|
When I tested the same Seagate TB portable Adapter with the Samsung 512GB SSD connected in Daisy chain with the Seagate TB desktop adapter to my MBP, all was working
fine, but now when connected directly to MBP, I get this disk disconnect problem. I suspected there is a power issue, because Samsung 830 series SSD draw a lot of power and when connected in daisy chain to Seagate desktop adapter the power for the Seagate TB portable adapter is NOT supplied from MBP, it will be supplied from the desktop adapter with own external power supply via the Elgato TB cable to the Seagate TB portable adapter.
Now the troubleshooting starts
|The test bench with all equipment used for troubleshooting|
|SATA extension with test points|
Inserted barrier strip with test points to attach multimeter and oscilloscope from Oscium to the SATA extension cable. I connected the multimeter and Oscium and running again the Black Magic Speed test and the copy the large 41Gb vmdk file. You get following result with the oscilloscope when the external SSD disconnects, measured between black and red wire, 5VDC supplied to SSD.
|Oscium 104 screen shoot, the drop of voltage to 1 VDC in the right of picture is when the SSD disconnects|
On the SATA cable from the portable adapter only both black ground/0VDC wires and the red +5VDC wires are used to supply power to the SSD.
If you test the same on the desktop adapter then also the yellow wire for +12VDC is used to power 3.5" SATA disks.
You see a voltage drop from +5VDC to about +1VDC and is about 12 ms wide on the top. Keep in mind that the scope does not have full sampling rates at this speed, so it is possible that very narrow drops/peaks maybe. This voltage drops to +1VDC stops the SSD (and disconnects the SSD) and the MBP will not get any signaling on the SATA connection and the used SW will shows the disconnect message. this can be repeated anytime when MBP, TB-cable and Seagate portable TB adapter gets hot.
Some thoughts about power over Thunderbolt connection
So whats the problem? Some investigation via Google shows that the Thunderbolt specifications from Intel are not public available, only to affiliated companies. So the only information I could gather about the power management on the thunderbolt cable is following:
On Display port, or when Display port equipment is used and power is needed, then PIN 20 on the connector carries +3.3VDC with maximum 500 mW
On Thunderbolt the power is increased and the source supplies 10Watts to Thunderbolt equipment via PIN 20 on Thunderbolt connector. I could not find any definitiv answer how high the voltage shall be. http://en.wikipedia.org/wiki/Thunderbolt_(interface) When you check the Texas Instruments Thunderbolt support chips documentation http://www.eetimes.com/electronics-products/electronic-product-reviews/analog-products/4238224/Chipset-family-supports-Thunderbolt-10-3-Gbps-interface-standard
To find the real source of the power "switch off" it would be necessary to make more measurements, specifically it would be necessary to measure the voltages on the Thunderbolt connector on MBP and also Seagate TB adapter during usage. for this a Thunderbolt breakout connector would be needed to attach the test strips. This would identify where the power cut off happens. I was not able to find a place to buy a Thunderbolt male and female connector, alone without cable and without electronics to build this breakout connector. I would appreciate if someone could let me know a source for this connectors to perform this tests.
How to make this work?
The problem seems to be that overall/average power consumption of the Samsung SSD is on the limit what the MBP (or other computer) can supply over the TB connection, but has sometimes current peaks above what the TB power controller when getting hot, in the MBP and or in the Seagate portable adapter will except, before switching off the power to protect the TB connection (the 12 ms drop of supply voltage).
The dirty way, but NOT recommended to solve this problem, is to use capacitors to store energy for this peak use. What works, you can connect following capacitors in parallel to black and red power supply lines on the SATA extension (observe the polarity of the Electrolytic capacitor)
- 1000 uF Electrolytic Capacitor, minimum 15VDC
- 10uF Film Capacitor, minimum 15VDC
- 10nF ceramic Capacitor, minimum 15VDC
- SATA extension cable short
Here the circuit, and how it looks
Why 3 different capacitors? each capacitor has different speed, the electrolytic capacitor stores the biggest energy but is slow, while the other 2 capacitor will act faster and on higher frequency, and shall suppress EMI and oscillating of power circuit.
Why shall this modification not be used? The 1000 uF capacitor has a very high inrush current, this means anytime you connect the Thunderbolt cable, the power controller has to regulate down the current until the capacitor is charged, and current over PIN 20 will go to the maximum current allowed......and in the longer run, may fry the TB connector in MBP or the TB cable.
Here the implementation I used for the test, it passes always the Black Magic Speed test and also to copy multiple 41GB vmdk files.
You need to use an external power supply for the SSD and the TB bus only powers the cable and the TB adapter circuit. This reduces also the power over the TB cable and hopefully also extends the contact live on the TB connector of MBP and TB cable. As I do not have any information how the power up timing and signaling is implemented in the TB connection, we must make sure that the power up timing is not changed when we use a external power supply. For this reason we need a relay that gets powered from the Seagate TB adapter (when the SSD shall get switched on) and then switches the power from the external power supply at the correct moment to the SSD when the TB cable is connected to the MBP. (external power supply needs to be connected to power line bevor you connect the TB cable to your MBP)
What we need:
- 5VDC 2 Amp stabilised power supply or a 5VDC external battery with minimum 4000mA and 2A current rating, like external battery for an iPad
- 5VDC Relay with low coil current (50mA or less) and single or multiple contacts to switch 2 Amp at 5VDC (you should switch 2 contacts in parallel for extended live)
- SATA extension cable
You can NOT use a dual USB cable to power the SSD from your Laptop's USB connectors! The power to your SSD connected via Thunderbolt must be a floating power supply, same as you can not power a USB hard disk from same power supply as your PC mother board is powered from (you would create a ground loop and bridge some circuits). If you do so, you can damage the laptop, Mac or Thunderbolt adapter, TB-cable, SSD or all of them. The minimum effect is that you will have a lot of data errors. So you must use an independent floating power supply or an independent battery.
Here the recommended circuit
Here the complete SATA cable with relay and PSU:
|SATA extension with relay switching 5VDC from external PSU to the SSD|
Some things to keep in mind
Does this MOD make any sense? You spend 99 bucks and have to add a relay and then also a stabilised 5VDC power supply and a couple of hours to make this work? Also the portable adapter has only one TB connector, so you can not daisy chain any other TB equipment.
In my opinion, using the Seagate TB desktop adapter with a short SATA extension cable is the better solution in the long run. (The desktop adapter comes already with a external power supply, has no power issues with large SSD's and for my knowledge has no thermal issues when used with 2.5" disks and a SATA extension)
For continuous use of your Thunderbolt devices (and also a Mac mini or iMac) You should keep in mind, special in countries with 110VAC line voltage, that there are a lot of power spikes, they do not effect the MBP, because it has a built in battery acting like a uninteruptible power supply, but all spikes will go thru any standard power supply to the TB adapter, and as known from this site http://support.apple.com/kb/HT5219?viewlocale=en_US any wrong sequence of connecting disconnecting Thunderbolt devices will lock them up. This means also when power spikes make the MBP believe the TB adapter was short time disconnected (indiced by power spikes) will cause a disk disconnect error message or will make your TB equipment "invisible" until you reboot your MBP again. To avoid this, you can use a small PC UPS to power the external power supply from the Seagate desktop adapter or when you use the portable adapter with the relay design you could power the portable adapter not with a power supply, but with an external battery (you need a high power version with minimum 4000mA capacity and 2 Amp current) similar like this http://store.apple.com/us/product/H6094ZM/A/mophie-juice-pack-powerstation-external-battery-for-iphone-ipad-and-ipod
You should read the FAQ/dont's listed by Apple http://support.apple.com/kb/HT5219?viewlocale=en_US and check the MAC forums that there are multiple complaints about sleep issues, or coming out of sleep with TB devices. I found out in the hard way that you can NOT have plugged in a Thunderbolt cable alone in your computer if on the other side of the TB cable is nothing plugged in. If your MBP will go to sleep with the TB-cable alone, the MBP crashes during sleep, or maybe when waking up from sleep and you have to boot up your MBP from a powered off state, needless to say that my W7-VM was crashed..... So avoid this.
I have my Mac always set to automatic sleep after few minutes, but I use Caffein http://lightheadsw.com/caffeine/ to prevent my MAC from sleep during testing or when I do important work.
Some Thunderbolt information:
Semtech TB cable transceiver
Intersil TB chip
Intel TB controller less then 3.4 W
Thunderbolt device reviews
Thunderbolt 10W, pin 20
Displayport and mini Displayport info
SSD tests with power consumption info
How to measure power consumption of SSD