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SATA-II explained - Revised 17/4/2007
Right, there have been many posts and threads recently asking about 'SATA-II' drives. This is a small explanation of these drives and what SATA-II really is.
SATA-II was the name of the organisation set up to write the specifications of the Serial ATA 2.5/2.6 generation drives and possibly beyond. It is not the name of a new drive standard. However, since the confusion caused by manufacturers of drives naming later drives SATA-II (a practice which is now dying off), they have changed their name to SATA-IO (Serial ATA International Organisation). It is important to note that SATA-II/SATA2 does not actually exist as a new drive standard and is merely a term sometimes used (erronously) to refer to drives which support some of the later SATA features.
Here is a small FAQ regarding SATA, SATA2, SATA-II, etc:
1. How many versions of SATA are there?
- There is currently only one version of the standard simply called 'SATA'. Extensions have been added to this in various generations of the specifications (currently up to generation 2.6) and these include support features such as the 3.0Gbit/s or 300MB/s (see point 4) interface speed, Native Command Queuing (NCQ), staggered spin up to name but a few. These extensions are optional and SATA drives can support as many or few of them as they like. Several suppliers still use the term SATA-II to refer to drives which support one or more of these extensions (particulaly the 3.0Gbit/s interface speed) - contrary to the wishes of the SATA International Organisation. Other companies (Seagate, Western Digital, etc) have now dropped the term.
For a table of the Serial ATA features, please see the table at the base of this mini-FAQ.
2. Is there a different power cable for 'SATA-II'/SATA300 drives or do I need an adapter?
- All SATA drives use the same type of power cable.
3. Is there a different data cable for 'SATA-II'/SATA300 drives?
- All SATA drives use the same type of data cable, regardless of whether they support the 3.0Gbit/s interface speed or not.
4. Why are some drives/controllers listed as SATA 300MB/s whereas others are listed as SATA 3.0Gbit/s? Which one is faster?
- Both are different terms used to refer to the same controller/drive speed. The 3.0Gbit/s rating means 3 Gigabits per second and is the raw speed with which the controller/drives operate at. Due to the 8b10b coding overhead which SATA uses, the actual uncoded transfer-rate is 2.4 Gbit/s which is the same as 300 Megabytes per second. Effectively though, both terms mean the same thing. The same applies to SATA150 compared with SATA 1.5Gbit/s.
5. Will my new 'SATA-II'/SATA300 drive work on my SATA150 controller (and vice versa)?
- All SATA drives should work with all controllers. This includes SATA300 drives working on SATA150 controllers and vice versa.
NOTE: Some SATA150 controllers do not support auto speed negotiation. When using a SATA300 drive with such a controller, it is necessary to change a jumper setting on the drive to force the drive to use the 150MB/s interface speed. The best approach is often to try the drive out and to change the jumper if the drive is not being detected in the BIOS when the system is powered up. Some owners of SATA300 drives may still experience problems however as some older SATA300 drives may require a firmware flash of their drive (in which case the manufacturer will need to be contacted). These issues arose as a result of manufacturer's bridging chip and firmware conflicts. Some drives have no jumpers e.g. Hitachi and require a firmware setting to be changed - see Q7 below. In most cases however, a SATA300 drive should function fine on a SATA150 controller.
6. Will I notice a big performance increase from a SATA300 drive over SATA150 drive with, for example the following extra features: 16MB cache and NCQ?
- No. The 3.0Gbit/s transfer rate would only come into play if you had a controller which supports the full 3.0Gbit/s transfer or a RAID array with probably at least 4 disks - a single 7200RPM drive will have a maximum external transfer rate of about 58MB/s (as opposed to the 300MB/s available). Thus, in single drive configurations, SATA300 drives show no increase over SATA150 or even IDE for that matter seeing as they will all have an external transfer rate of around 55-60MB/s (7200rpm drives only).The only performance increase you will see is through the 16MB cache (should help writing and reading performance) and NCQ (Native Command Queuing) so long as your motherbard supports it. Thus, the performance increase will not be great over SATA150 drives, if at all, depending on features of the specific drive.
7. Will my SATA300 drive work out of the box at the full interface speed of 3.0Gbit/s - I have a compatible motherboard?
- Yes, for the most part. Hitachi drives are slightly different. For compatibility reasons, Hitachi default their drives to 1.5Gbit/s. To enable the 3.0Gbit/s interface speed on Hitachi's, you must download their Feature Tool and enable it from within DOS.
8. Can I run a SATA300 drive with a SATA150 drive and still get the full rate on the SATA300 drive?
- Yes. They will be on separate channels and so long as your SATA controller supports 3.0Gbit/s transfer rate, then they will run as intended. The same applies to combining drives where only one drive supports features such as NCQ as well.
9. How can I tell if my SATA300 drive is running at its intended 3.0Gbit/s, I have full support for it?
- If you have an nForce 4 board with the nF4 SATA drivers installed, the easy way is to look in Device Manager. Look at the properties of the SATA controllers under IDE ATA/ATAPI controller and there is a tab in there which displays either SATA Generation 1-1.5G for SATA150 and SATA Generation 2-2.5 (iirc) for SATA300. Otherwise, please download HDTach. Perform a quick test on the relevant drive and look at the burst speed. SATA150 will max out before 150MB/s but SATA300 will surpass this up to 300MB/s.
The actual specifications for Serial ATA drives can be found in this table:
Notice how many features are actually optional. Thus, ensure you know the actual specifications of the drive before purchasing.
Major thanks to Trippynet for re-writing the sticky to bring it up to date
Right, there have been many posts and threads recently asking about 'SATA-II' drives. This is a small explanation of these drives and what SATA-II really is.
SATA-II was the name of the organisation set up to write the specifications of the Serial ATA 2.5/2.6 generation drives and possibly beyond. It is not the name of a new drive standard. However, since the confusion caused by manufacturers of drives naming later drives SATA-II (a practice which is now dying off), they have changed their name to SATA-IO (Serial ATA International Organisation). It is important to note that SATA-II/SATA2 does not actually exist as a new drive standard and is merely a term sometimes used (erronously) to refer to drives which support some of the later SATA features.
Here is a small FAQ regarding SATA, SATA2, SATA-II, etc:
1. How many versions of SATA are there?
- There is currently only one version of the standard simply called 'SATA'. Extensions have been added to this in various generations of the specifications (currently up to generation 2.6) and these include support features such as the 3.0Gbit/s or 300MB/s (see point 4) interface speed, Native Command Queuing (NCQ), staggered spin up to name but a few. These extensions are optional and SATA drives can support as many or few of them as they like. Several suppliers still use the term SATA-II to refer to drives which support one or more of these extensions (particulaly the 3.0Gbit/s interface speed) - contrary to the wishes of the SATA International Organisation. Other companies (Seagate, Western Digital, etc) have now dropped the term.
For a table of the Serial ATA features, please see the table at the base of this mini-FAQ.
2. Is there a different power cable for 'SATA-II'/SATA300 drives or do I need an adapter?
- All SATA drives use the same type of power cable.
3. Is there a different data cable for 'SATA-II'/SATA300 drives?
- All SATA drives use the same type of data cable, regardless of whether they support the 3.0Gbit/s interface speed or not.
4. Why are some drives/controllers listed as SATA 300MB/s whereas others are listed as SATA 3.0Gbit/s? Which one is faster?
- Both are different terms used to refer to the same controller/drive speed. The 3.0Gbit/s rating means 3 Gigabits per second and is the raw speed with which the controller/drives operate at. Due to the 8b10b coding overhead which SATA uses, the actual uncoded transfer-rate is 2.4 Gbit/s which is the same as 300 Megabytes per second. Effectively though, both terms mean the same thing. The same applies to SATA150 compared with SATA 1.5Gbit/s.
5. Will my new 'SATA-II'/SATA300 drive work on my SATA150 controller (and vice versa)?
- All SATA drives should work with all controllers. This includes SATA300 drives working on SATA150 controllers and vice versa.
NOTE: Some SATA150 controllers do not support auto speed negotiation. When using a SATA300 drive with such a controller, it is necessary to change a jumper setting on the drive to force the drive to use the 150MB/s interface speed. The best approach is often to try the drive out and to change the jumper if the drive is not being detected in the BIOS when the system is powered up. Some owners of SATA300 drives may still experience problems however as some older SATA300 drives may require a firmware flash of their drive (in which case the manufacturer will need to be contacted). These issues arose as a result of manufacturer's bridging chip and firmware conflicts. Some drives have no jumpers e.g. Hitachi and require a firmware setting to be changed - see Q7 below. In most cases however, a SATA300 drive should function fine on a SATA150 controller.
6. Will I notice a big performance increase from a SATA300 drive over SATA150 drive with, for example the following extra features: 16MB cache and NCQ?
- No. The 3.0Gbit/s transfer rate would only come into play if you had a controller which supports the full 3.0Gbit/s transfer or a RAID array with probably at least 4 disks - a single 7200RPM drive will have a maximum external transfer rate of about 58MB/s (as opposed to the 300MB/s available). Thus, in single drive configurations, SATA300 drives show no increase over SATA150 or even IDE for that matter seeing as they will all have an external transfer rate of around 55-60MB/s (7200rpm drives only).The only performance increase you will see is through the 16MB cache (should help writing and reading performance) and NCQ (Native Command Queuing) so long as your motherbard supports it. Thus, the performance increase will not be great over SATA150 drives, if at all, depending on features of the specific drive.
7. Will my SATA300 drive work out of the box at the full interface speed of 3.0Gbit/s - I have a compatible motherboard?
- Yes, for the most part. Hitachi drives are slightly different. For compatibility reasons, Hitachi default their drives to 1.5Gbit/s. To enable the 3.0Gbit/s interface speed on Hitachi's, you must download their Feature Tool and enable it from within DOS.
8. Can I run a SATA300 drive with a SATA150 drive and still get the full rate on the SATA300 drive?
- Yes. They will be on separate channels and so long as your SATA controller supports 3.0Gbit/s transfer rate, then they will run as intended. The same applies to combining drives where only one drive supports features such as NCQ as well.
9. How can I tell if my SATA300 drive is running at its intended 3.0Gbit/s, I have full support for it?
- If you have an nForce 4 board with the nF4 SATA drivers installed, the easy way is to look in Device Manager. Look at the properties of the SATA controllers under IDE ATA/ATAPI controller and there is a tab in there which displays either SATA Generation 1-1.5G for SATA150 and SATA Generation 2-2.5 (iirc) for SATA300. Otherwise, please download HDTach. Perform a quick test on the relevant drive and look at the burst speed. SATA150 will max out before 150MB/s but SATA300 will surpass this up to 300MB/s.
The actual specifications for Serial ATA drives can be found in this table:
Notice how many features are actually optional. Thus, ensure you know the actual specifications of the drive before purchasing.
Major thanks to Trippynet for re-writing the sticky to bring it up to date
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