# Ocz agility3 low speed (SSD)

## gentoorockerfr

Hello ,

these are the results/infos i took from terminal

hdparm -Tt /dev/sdb

```

/dev/sdb:

Timing cached reads: 7420 MB in 2.00 seconds = 3711.45 MB/sec

Timing buffered disk reads: 500 MB in 3.01 seconds = 165.85 MB/sec
```

it have to be like this

```
Timing cached reads: 27738 MB in 2.00 seconds = 13889.38 MB/sec

Timing buffered disk reads: 1158 MB in 3.01 seconds =385.08 MB/sec
```

Why?How can i solve it?

The disk is like a normal.

I am waiting for your help

thank you

----------

## whiteghost

from my agility 2 60G

```
# hdparm -Tt /dev/sda

/dev/sda:

 Timing cached reads:   7528 MB in  2.00 seconds = 3764.76 MB/sec

 Timing buffered disk reads: 638 MB in  3.01 seconds = 212.20 MB/sec

```

 *Quote:*   

> Timing cached reads: 27738 MB in 2.00 seconds = 13889.38 MB/sec 
> 
> Timing buffered disk reads: 1158 MB in 3.01 seconds =385.08 MB/sec

 

sounds ridiculous to me

----------

## gentoorockerfr

https://wiki.archlinux.org/index.php/SSD_Benchmarking#OCZ-AGILITY3_120GB

----------

## gentoorockerfr

Any help please?

@whiteghost 	

PostPosted: Mon Jun 04, 2012 6:45 pm    Post subject:

from my agility 2 60G

Code:

# hdparm -Tt /dev/sda

/dev/sda:

 Timing cached reads:   7528 MB in  2.00 seconds = 3764.76 MB/sec

 Timing buffered disk reads: 638 MB in  3.01 seconds = 212.20 MB/sec

so you are faster than me and you have agility 2!

----------

## WorBlux

Just curious, what sort of motherboard do you have?

----------

## whiteghost

do you have a sata 3 connection?

i've never seen anyone match the benchmark posted at archlinux forum, so i am skeptical.

i use a desktop and have lots of memory and hdd.

so i mount /var/tmp/portage and /tmp  tmpfs in fstab.

i make my distfiles directory /distfiles and mount on a hdd.

i used to not use swap but have recently made swap on hdd.

i use gparted to partition and it has option to align to MiB

use ahci driver and try not to fill over 70 %

http://www.ocztechnologyforum.com/forum/showthread.php?97693-is-certain-amount-of-free-space-required-for-optimal-performance

that is about all you can do. 

while i have gone to lengths to avoid writes a person also should not be afraid to use their ssd. it should last a long time.

----------

## eccerr0r

Not same machine or disk, but numbers are very possible... but machine dependent.

```
Timing cached reads: 29206 MB in 2.00 seconds = 14624.82 MB/sec

Timing buffered disk reads: 1128 MB in 3.00 seconds = 375.98 MB/sec
```

Not using the same disk, but still SSD: Core i7/z68/SSD520

Yes, SATA3 (6Gb/sec) is needed to get this high...  Make sure you're using a good cable and a SATA3 port.  There's only 2 on my z68 board...

----------

## whiteghost

 *eccerr0r wrote:*   

> Not same machine or disk, but numbers are very possible... but machine dependent.
> 
> ```
> Timing cached reads: 29206 MB in 2.00 seconds = 14624.82 MB/sec
> 
> ...

 

i looked at the specs for agility 3 and intel 520 at newegg, very close.

----------

## gentoorockerfr

my specs 

AMD Phenom(tm) II X4 955 Processor

ASRock 890GM Pro3 R2.0

6gb ddr3 1600 ram

i think <<good>> sata cable and sata 3 port..

and the disk has 35% available space

----------

## gentoorockerfr

So any help please?Whats the error-problem?

----------

## steffie

 *gentoorockerfr wrote:*   

> So any help please?Whats the error-problem?

 

ASRock Z68 Pro3-M, SAMSUNG 470 64.0GB

hdparm -Tt /dev/sda

/dev/sda:

 Timing cached reads:   20418 MB in  2.00 seconds = 10220.55 MB/sec

 Timing buffered disk reads: 706 MB in  3.00 seconds = 234.96 MB/sec

PCI bridge: ASMedia Technology Inc. ASM1083/1085 PCIe to PCI Bridge

----------

## eccerr0r

I do have to say something is strange - how old is the AsRock 890GM board?

It's weird that it has 5 SATA 6Gb ports but my Z68 (Gigabyte Z68AP-D3) only has two... Apparently Intel thinks sata 6Gb ports are hard to attach and therefore only offers 2...  Not sure if it's the motherboard limiting the speed or not.

How are the SATA6Gb attached to the cpu, does it go through the southbridge (bad)?  When you're using hdparm to test, it should not care about fragmentation much, as fragmentation really affects small writes.

steffie: what CPU do you have?  Curious how much the CPU determines the cached read speeds versus the chipset/disk...

----------

## gentoorockerfr

My motherboard is this

http://www.asrock.com/mb/overview.asp?model=890gm%20pro3%20r2.0

How are the SATA6Gb attached to the cpu, does it go through the southbridge (bad)? When you're using hdparm to test, it should not care about fragmentation much, as fragmentation really affects small writes. 

could you explain it?

----------

## Naib

When you partitioned the drive did you ensure it was aligned to 4k as oppose to 512?

by default fdisk will partition assuming a 512b sector size, which is valid for old HDD

Newer HDD as well as SSD have sector sizes of 4096 (so they don't run out of indexing). Thing is if you partition the drive without taking this into consideration and the partition/s are NOT aligned to these clusters you end up in a situation where reads/writes require spanning 2 sectors to complete resulting in additional commands being issued to the controller

----------

## gentoorockerfr

```
fdisk /dev/sdb1

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building a new DOS disklabel with disk identifier 0xd52ef117.

Changes will remain in memory only, until you decide to write them.

After that, of course, the previous content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
```

```

fdisk -lu /dev/sdb

Disk /dev/sdb: 60.0 GB, 60022480896 bytes

255 heads, 63 sectors/track, 7297 cylinders, total 117231408 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x000550b3

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048   117229567    58613760   83  Linux
```

So whats my next move?

----------

## eccerr0r

The port connection issue is very technical but it boils down to the latency and bottlenecks involved when passing data through the channels.  Now I don't know too much about AMD Hypertransport unfortunately, only have some rudimentary knowledge about Intel QPI, but I have to assume they have some similarities.  The SATA controllers can be connected to the first level QPI where bandwidths are highest but there are a limited number of connections.  One possibility to increase the number of connections is to put it on a bridge to multiplex more connections, usually the southbridge.  There's latency and delays involved there which will slow down throughput.

The sector fragmentation is an interesting possibility but if you hdparm on the raw device like /dev/sda, etc., this should be aligned to the first sector/sector 0, which should be aligned to any sector size, or at least I would hope it to be the case...  With newer versions of fdisk starting at sector 2048 this should be aligned to 4096 byte-sectors as long as your partitions are a multiple of 4096 bytes.

----------

## gentoorockerfr

can  i change alignment to 4k without delete/format the disk?

ps so the problem exist because disk's alignment?512b instead of 4k?

----------

## eccerr0r

I think it already is, but you can't really redo without erasing everything (though gparted might be able to do something).

Start sector 2048 (versus 63, because old versions of fdisk aligned to "track" which makes sense for very old disks) is a multiple of 4096 since 2048*512 is a multiple of 4096 - it's the 256th 4096 sector.

I'm still convinced it's a motherboard issue at the moment.

----------

## gentoorockerfr

could you tell me please how to format a ssd disk to have full performance.What about gptfdisk?

Also what these lines said?

255 heads, 63 sectors/track, 7297 cylinders, total 117231408 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

ps how could i overtake motheboard issue?

----------

## Naib

```

fdisk -lu /dev/sdb

Disk /dev/sdb: 60.0 GB, 60022480896 bytes

255 heads, 63 sectors/track, 7297 cylinders, total 117231408 sectors

Units = sectors of 1 * 512 = 512 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x000550b3

   Device Boot      Start         End      Blocks   Id  System

/dev/sdb1            2048   117229567    58613760   83  Linux
```

See that looks like 512b blocksize.

cat /sys/block/sda/queue/physical_block_size

4096

cat /sys/block/sda/queue/logical_block_size

512

----------

## gentoorockerfr

yes...

```
cat /sys/block/sda/queue/physical_block_size 

512

cat /sys/block/sda/queue/logical_block_size 

512
```

why..

i think that i partioned this disk with gparted...

could you tell me please how to format a ssd disk to have full performance.What about gptfdisk?

whats next move?

thank you for your time

----------

## eccerr0r

Motherboard issue meaning: replace motherboard with another brand and/or newer chipset that has the SATA ports attached differently to hypertransport.

This is if you're sure you're using the correct driver for the SATA chipset.

Granted I don't know enough about AMD bus structures and chipsets (other than the fact that my AthlonXP + SiS and AthlonXP + nVidia chipset systems seem a little slow to PATA IDE cache), but the Intel Z68 seems to do fine...

----------

## gentoorockerfr

so there is not any problem because of 512b alignment of my ssd?

----------

## Naib

 *gentoorockerfr wrote:*   

> so there is not any problem because of 512b alignment of my ssd?

 

if you are convinced sure.

http://www.osnews.com/story/22872/Linux_Not_Fully_Prepared_for_4096-Byte_Sector_Hard_Drives

There are lots of litature out there detailing why having an unaligned can cause issues

----------

## eccerr0r

Imagine if hard drives "Bus Errors" when someone does an unaligned access...

(sorry about this bad, obscure joke related to how some CPUs will bus error when doing unaligned accesses.  Once again this is a performance related issue on CPUs too!  Then again the bus errors were meant to make people rewrite their code, maybe we need to do this for HDDs too...)

----------

## Yczo

I have connected the agility 3 sata III through the sata II interface of my Dell xps 15 lx501  i7 quad 1700 MHz.

This is my test:

/dev/sda:

 Timing cached reads:   6002 MB in  2.00 seconds = 3004.03 MB/sec

 Timing buffered disk reads: 632 MB in  3.01 seconds = 210.02 MB/sec

Something is wrong for me too. I should have over 7000 MB/sec on sata II, guess

Regards

----------

## fhaddad78

Make sure you have AHCI mode enabled in the BIOS and in the kernel. I have an old Intel X-25M G1 160GB and I get:

```
hdparm -Tt /dev/sda

/dev/sda:

 Timing cached reads:   25210 MB in  2.00 seconds = 12618.95 MB/sec

 Timing buffered disk reads: 794 MB in  3.00 seconds = 264.36 MB/sec
```

----------

