Performance tweaks and partition alignment for OCZ Agility 60GB SSD

I have the OCZ Agility 60GB SSD with:
* Seek Time: < .1ms
* Read: Up to 185 MB/s
* Write: Up to 100 MB/s
* Sustained Write: Up to 60 MB/S

I do not notice any problems with it, I understand that many of the tweaks out there were originally meant to vastly improve performance of the slower SSDs not the faster ones.

I have a triple boot, Win 7 and Win XP on SSD and Vista on a 7200 RPM mechanical Samsung.


Partitions on the SSD are
1. Win 7
2. Win XP
3. Program Files for both


Should I do Partition alignment as described here for Win 7 and XP and Program Files partitions?

Should I just align the Windows XP partition? What are the benefits for a fast SSD? I need to reimage it back using the existing image.

Should I do it by booting into Vista which is not on the SSD and aligning the partitions from there?

Should I disable Windows XP prefetcher as described here and enable power protect cache (dskcache) even though I have a fast SSD and notice no problems whatsoever in either Windows 7 or Windows XP?

_____________________
Intel i7 920 [200] BCLK x 19 = 3.80 GHz @ [1.4000] CPU Voltage & [1.35000] QPI/DRAM Uncore Voltage, Batch 3836A394
3 x 1GB G.SKIL DDR3 1333 (PC3 10666) [DDR3-1691MHz] 10-10-10-24 @ 1.64 DRAM Bus Voltage
ASUS P6T Deluxe v.1 [LGA 1366 Intel X58] BIOS 1606
Thermalright Ultra-120 eXtreme 1366 RT with 120mm Scythe S-Flex F fan
ASUS EAH4850 TOP Radeon HD 4850 512MB @ 680 MHz GPU & 2100 MHz Memory
OCZ Agility 60GB SSD
Antec nine hundred case, two front 120mm fans, one back 120mm Fan, one top 200mm fan
Corsair CMPSU-750TX 750W

you need to offset the first partition correctly. cus if the first one isnt set correctly... the ones after it wont be and even then you still need to align subsequent ones.

OK. So align the first partition, then all the other ones after that? And should I bother with the second part (prefetch, etc.) if I notice no hickups whatsoever?


What kind of space savings are we talking about on a 60 GB SSD using partition alignment?

c627627 said:

OK. So align the first partition, then all the other ones after that? And should I bother with the second part (prefetch, etc.) if I notice no hickups whatsoever?


What kind of space savings are we talking about on a 60 GB SSD using partition alignment?

Click to expand...

ya make sure all partitions are aligned at least to 64KB (128 sector) offset. You could play with the other stuff (disable 8dot3 names... no one needs those) and u might consider enabling power protect cache.

As far as space savings it depends... its definietly going to save some... that could be anywhere from 10mb to 1gb at 30gbs of usage.

When I change the BIOS setting to AHCI, I blue screen before Windows loads.


I have a few SATA drives and an IDE burner.


_____________________
Intel i7 920 [200] BCLK x 19 = 3.80 GHz @ [1.4000] CPU Voltage & [1.35000] QPI/DRAM Uncore Voltage, Batch 3836A394
3 x 1GB G.SKIL DDR3 1333 (PC3 10666) [DDR3-1691MHz] 10-10-10-24 @ 1.64 DRAM Bus Voltage
ASUS P6T Deluxe v.1 [LGA 1366 Intel X58] BIOS 1606
Thermalright Ultra-120 eXtreme 1366 RT with 120mm Scythe S-Flex F fan
ASUS EAH4850 TOP Radeon HD 4850 512MB @ 680 MHz GPU & 2100 MHz Memory
OCZ Agility 60GB SSD
Antec nine hundred case, two front 120mm fans, one back 120mm Fan, one top 200mm fan
Corsair CMPSU-750TX 750W

you will need to set it to ACHI in the bios THEN install windows.

Windows uses different drivers for IDE and AHCI mode. So if you change the BIOS to AHCI mode without first telling Windows to load AHCI drives you get a bluescreen. Use these instructions to change to AHCI drivers in Windows before changing to AHCI mode in BIOS.

You can also load the AHCI drivers in windows then change it....

Alpha got it...should have refreshed before I replied.

Oh. Remind me again why I need to bother with this for SSD?

_____________________
Intel i7 920 [200] BCLK x 19 = 3.80 GHz @ [1.4000] CPU Voltage & [1.35000] QPI/DRAM Uncore Voltage, Batch 3836A394
3 x 1GB G.SKIL DDR3 1333 (PC3 10666) [DDR3-1691MHz] 10-10-10-24 @ 1.64 DRAM Bus Voltage
ASUS P6T Deluxe v.1 [LGA 1366 Intel X58] BIOS 1606
Thermalright Ultra-120 eXtreme 1366 RT with 120mm Scythe S-Flex F fan
ASUS EAH4850 TOP Radeon HD 4850 512MB @ 680 MHz GPU & 2100 MHz Memory
OCZ Agility 60GB SSD
Antec nine hundred case, two front 120mm fans, one back 120mm Fan, one top 200mm fan
Corsair CMPSU-750TX 750W



To resolve this issue, enable the AHCI driver in the registry before you change the SATA mode of the boot drive. To do this, follow these steps:

1. Exit all Windows-based programs.
2. Click Start, type regedit in the Start Search box, and then press ENTER.
3. If you receive the User Account Control dialog box, click Continue.
4. Locate and then click one of the following registry subkeys:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\IastorV
5. In the right pane, right-click Start in the Name column, and then click Modify.
6. In the Value data box, type 0, and then click OK.
7. On the File menu, click Exit to close Registry Editor.

NCQ is only enabled with AHCI.

W7 should do most of this for you but check...: Disable Superfetch, Indexing on that drive, defrag schedule, To save space I vlite'd the W7 install and cut out hibernation, restore, sleep, etc...

I disabled the heck out of my Windows 7 already: http://www.ocforums.com/showthread.php?t=616200

Check on all except for Superfetch, I think the word is to keep that on.


Can you tell me what real world difference NCQ / AHCI would bring to me:

_____________________
Intel i7 920 [200] BCLK x 19 = 3.80 GHz @ [1.4000] CPU Voltage & [1.35000] QPI/DRAM Uncore Voltage, Batch 3836A394
3 x 1GB G.SKIL DDR3 1333 (PC3 10666) [DDR3-1691MHz] 10-10-10-24 @ 1.64 DRAM Bus Voltage
ASUS P6T Deluxe v.1 [LGA 1366 Intel X58] BIOS 1606
Thermalright Ultra-120 eXtreme 1366 RT with 120mm Scythe S-Flex F fan
ASUS EAH4850 TOP Radeon HD 4850 512MB @ 680 MHz GPU & 2100 MHz Memory
OCZ Agility 60GB SSD
Antec nine hundred case, two front 120mm fans, one back 120mm Fan, one top 200mm fan
Corsair CMPSU-750TX 750W

Real world, no idea. But enabling AHCI overall improved my drive performance. Here is what it does on an intel drive:

As one might expect from a company with a long history of developing core-logic chipsets, the X25-M's storage controller is an Intel design—and a smart one at that, with support for, ahem, SMART monitoring. More interestingly, the controller supports Native Command Queuing (NCQ)—a new trick for SSDs. NCQ was developed to reduce the performance impact of mechanical latency found in traditional hard drives, so it's might seem like an odd choice for a solid-state drive with no mechanical parts. According to Intel, its SSDs are so fast that NCQ helps to compensate for latency encountered in the host PC. Even today's fastest systems take some time (time is relative in the microsecond world of the SSD) between when a request is completed and another one is issued. Queuing up multiple requests can keep a solid-state drive busy during this downtime, and the X25-M is capable of stacking requests 32 deep.

Click to expand...

There are a lot of SSDs out there, but most are not up to the performance of Intel SSDs and OCZ Agility & Vertex.


So what does NCQ / AHCI do for Intel or Agility/Vertex SSD on a i7 920 home system at 4 GHz.

If I can dig up my screenshots pre AHCI and post AHCI I will. Otherwise, I will refer you back to the excerpt I quoted above as that was about an Intel drive anyway. Sorry I cant say "it will cut your boot time by 2 seconds" as I know that is what you are looking for.

Reading and writing to flash chips isn't all that fast. The way SSD get such high speeds (both sequential and random) is by having multiple channels (10 for the Intel controller, for example) and then reading and writing to multiple flash chips at once. Sort of like a really sophisticated RAID0 setup. Except where RAID0 is just dumbly striping across drives the SSD controller is dynamically optimizing it all the time.

In AHCI mode you get Native Command Queuing, NCQ, which lest the drive reorder IO in the queue. By reordering the IOs the SSD controller can keep as many channels as possible operating in parallel.

For example there are a bunch of reads in the queue to chip on channel A and behind them a read to the chip on channel B. NCQ lets the controller pick that read to the channel B out of the queue and do it at the same time as it continues to work on the read to channel A. The Intel controller excels at this. Its random read almost doubles by enabling NCQ, and the more commands you feed it the more efficiently it can use its 10 channels and the faster it gets. The indilinx controller, with only four channels, doesn't scale as well.

I see. I believe the topic of this thread OCZ Agility uses the indilinx controller.


It therefore stands to benefit less. While of course, it's best to enable AHCI from the get go, I question the real life benefits of this because I would have to manually edit multiple operating systems (I have a multi-boot), I'll probably do it but I am looking to understand the real life benefits for indilinx based drives.

For the record, it appears to be next to impossible to enable AHCI on already installed Windows XP and since I have a multi boot which includes Windows XP, there's nothing I can do other than reinstall Windows XP, which is not going to happen at this time so



EDIT: Yes there can:

http://www.overclockers.com/forums/showthread.php?t=648104

Is there any way to check what your current alignment is? I bought a Vertex series 60GB today and Win7 installed on it without requiring me to change anything (didn't need to upgrade firmware, align the drive, etc.. as I heard earlier models required you too).

I want to make sure I'm getting the most out of my drive and have completed a lot of the steps mentioned in this thread and in the OCZ threads, but can't seem to figure out what my current alignment is.

AS SSD Benchmark will check alignment for you, but Windows 7 should align things properly for you.

also last time i read the barefoot controller cant handle AHCI. Tony at ocz said to stick with IDE mode. like i said last time i read but that might have changed with newer FW's.