I have a Mushkin Enhanced Chronos 120GB SSD (http://www.mushkin.com/Digital-Storage/SSDs/MKNSSDCR120GB.aspx). Its performance is rated as:

Capacity: 120GB

Read Speed: up to 550MB/sec

Write Speed: up to 515MB/sec

Controller: SF-2281

Interface Type: SATA 3.0 (6Gb/s)

IOPS: 90,000 (4K random write, 4K aligned)

My performance however is much lower.

Screenshots from HD Tune Pro 5.00:

enter image description here

I am however using this on a SATA2 port, while it is a SATA3 SSD.

The other hardware:

Motherboard: Gigabyte ga-ma790xt-ud4p (http://www.gigabyte.us/products/product-page.aspx?pid=3010#ov) (latest BIOS (F8))

Processor: AMD Phenom II x4 955 BE

RAM: 16GB (4x4) Corsair Vengeance (http://www.corsair.com/vengeance-8gb-dual-channel-ddr3-memory-kit-cmz8gx3m2a1600c9.html

Graphics card: ATI Radeon HD4890 1GB (http://www.amd.com/us/products/desktop/graphics/ati-radeon-hd-4000/hd-4890/pages/ati-radeon-hd-4890-overview.aspx

It has always been this slow, I haven't seen the performance go down since I started using it.

EDIT:

Here's a screenshot from ATTO. It looks a bit better then HD Tune Pro.

enter image description here

After enabling AHCI:

enter image description here

Simon Verbeke

Posted 2012-05-04T18:53:28.863

Reputation: 3 553

I'm curious about an answear, according to wikipedia, SATA2 can reach 300MB/s, while yours is running on 150MB/s only.

– Diogo – 2012-05-04T19:20:24.203

@DiogoRocha I do get bursts of up to 200MB. – Simon Verbeke – 2012-05-04T19:29:54.683

But the average is about 150MB/s, half of nominal capacity. – Diogo – 2012-05-04T19:40:50.453

Let me leave this link here. I didn't tested any of these recomendations(backup everything before if you want to test) and post your results here if it works. I was looking for a reference for SSD performance improvement that I saw once that says to create a free(1MB) space before the OS on your SSD space but I didn't found it.

– Diogo – 2012-05-07T16:28:47.417

Also, take a look here. Hope this helps.

– Diogo – 2012-05-07T16:30:35.497

Also run AS SSD benchmarks

– Sathyajith Bhat – 2012-05-07T17:10:49.480

@Sathya: Some interesting results here. Seems that I only enabled AHCI for my regular HDD. – Simon Verbeke – 2012-05-07T17:43:25.540

@Sathya This seems to have fixed it! Doubled my speed with the low file sizes in ATTO and increased the speed of the high file sizes by 40MB/s – Simon Verbeke – 2012-05-07T18:16:13.233

1@SimonVerbeke Cool :-) enjoy your new SSD :-) – Sathyajith Bhat – 2012-05-07T18:35:31.540

@DiogoRocha: Your suggestions helped a bit too, thanks! – Simon Verbeke – 2012-05-07T18:46:17.613

Answers

The first problem you have is that you are using HDTune for the benchmark. The way it does its benchmarking is to try and map out how the performance of a hard drive changes as you move across the platter. This type of access is a worst case for SSDs and does not lend itself to pushing an SSD as far as it can go. The rating for SSDs are usually done with ATTO Disk Benchmark. As a benchmark ATTO has the opposite problem. It is a best case scenario, which is why the ratings say "up to".

Also, being on SATAII will limit you to around 260-280MB/s.

Another common cause of not getting the expected speeds from a SSD is if the SATA controller is in IDE emulation mode instead of in AHCI mode.

Mr Alpha

Posted 2012-05-04T18:53:28.863

Reputation: 6 391

I remember something about the AHCI mode. I believe I tried to set that when I had recently installed the SSD, but that I kept getting BSOD's while booting and had to disable it again. – Simon Verbeke – 2012-05-04T21:22:12.853

Windows does not enable the ACHI drives if you install in IDE mode so it won't be able to boot if you later switch to AHCI mode. The fix is simple and found here http://support.microsoft.com/kb/922976 That will allow you to enable the Microsoft AHCI drivers. It may still be the case they you'll want to reinstall the platform specific AHCI drivers.

– Mr Alpha – 2012-05-04T21:31:32.807

I'll first finish this benchmark, and then I'll try turning AHCI mode on. – Simon Verbeke – 2012-05-04T21:35:22.073

I thought access time and read speed was the same accross all cells of an SSD - can you explain how this a "worst case for SSD"? – mtone – 2012-05-04T21:56:14.543

Enabled AHCI and rerun the benchmark. The results stay the same – Simon Verbeke – 2012-05-04T22:00:56.317

Individual NAND dies are actually quite slow. An SSD gets it speed from the controller being able to spread out a given workload across its array of NAND dies. How well it manages this depends on how parallelizable the workload is. – Mr Alpha – 2012-05-04T22:01:08.277

It looks as if you may not have NCQ enabled, although it is a bit hard to tell since you lowered the queue depth to 2. I remember reading about people having to enable NCQ separately on some AMD platforms. Even so it should go up towards 260000K at least. I suppose it might be some limitation of the SATA controller. – Mr Alpha – 2012-05-04T22:08:40.013

@MrAlpha How can I tell if I have enabled NCQ? – Simon Verbeke – 2012-05-04T22:19:57.587

The result for the small IOs (ie 0.5-32.0) should increase as you increase queue depth in ATTO if you have NCQ enabled. I'm sure there also is some setting in a driver or such you can look at but I am not very familiar with the AMD platform so I cannot help you there. – Mr Alpha – 2012-05-05T09:23:27.537

@MrAlpha Reran the benchmark with queue depth 10, and the performance increased significantly. – Simon Verbeke – 2012-05-05T13:16:31.430

Well, that implies you have NCQ enabled. I'm still unsure as to why you are limited to 200MB/s. AMD used to have issues with SSD performance but all that was sorted out in a series of BIOS and driver updates. – Mr Alpha – 2012-05-05T13:31:10.310

@MrAlpha It seems it was AHCI after all. The benchmark that Sathya metioned also showed wether AHCI was enabled. Appears that I had only enabled it for my regular HDD. Performance is way higher now! Thank you – Simon Verbeke – 2012-05-07T18:17:19.723

Troubleshooting slow SSD

The other hardware:

EDIT:

Answers