Sandisk Plus has worst Win7+AHCI performance

System AMD X6
12GB RAM, GTX660
SSD Sandisk Plus (OS: Win7 64bit)
SSD Intel (OS: XP 32bit)
1TB HDD Toshiba

I upgraded from the 120GB Sandisk Plus to the 240GB Sandisk Plus, because I was thinking the bigger version must be faster.
Well, I was wrong - the 240GB Sandisk is a lot slower. ^^

New Sandisk Plus 240GB (fresh Win7 Install)
Win7 64bit AHCI Mode:  231mb/s read - 100mb/s write
Win7 64bit Native IDE Mode:  211mb/s read - 180mb/s write
If you dont believe it:
Look at the screenshot, just 100mb/s seq write under AHCI, this is really worst, even my old Toshiba HDD performs better. :cry:

Old Intel 240GB SSD (same PC, same OS)
Win7 64bit AHCI Mode: 257mb/s read - 208mb/s write
Win7 64bit Native IDE Mode: 184mb/s read - 182mb/s write

I added the Intel as compare if this proofs nothing is wrong with my OS or mainboard.
The Intel (same for the 120GB Sandisk) perform like it should be = they are faster in AHCI Mode and slower in IDE Mode.
Just the 240GB Sandisk version is slow like a turtle under Win7/AHCI and this makes me so curious that I finally tested it also under Windows XP:  
Sandisk Plus 240GB   (XP 32 bit - IDE Mode):
241mb/s read / 203mb/s write

Unbelievible, but true - the Sandisk performs best under the old XP + IDE Mode ^^ :dizzy_face:
Well, since there is no Sandisk trim tool for XP = the Sandisk is not good for XP in the long run - but on the other side, this SSD is also not any good for Win7+AHCI if the write performance is so bad & slow.

So my questions are:
Why has the 240GB Sandisk such pretty poor Win7+AHCI performance ???
Why is there no (XP) trim tool?

thx. Peter

Hi Petex, is the drive connected to SATA III port ? 

it is a SATA-II Board, but the (slower) SATA-II interface didnt explain all this. 
If you look at the screenshot - you will see that the Sandisk Plus is able to do up to 241mb/s with SATA-II under XP (IDE Mode), but regardless if I choose IDE or AHCI  ->>  the SSD did not show the same performance under Win7.

Sandisk 240GB Win7 IDE Mode read/write rate is 20% slower (compared to XP)
Sandisk 240GB Win 7 AHCI Mode write rate is 100% slower (compared to IDE Mode & my previous 120GB Sandisk Plus)

All my other SSDs didnt have such strange Win7 performance problems.
Yours 120GB version was doing fine.

Hi Petex,

This SSD is designed to reach its maximium performance under SATA III port, under SATA II there is no published expected performance data, so we can not troubleshoot from there. 

Do you have access to another SATA III system or PC and can you test the performance on there? It will help if we can verify the drive is doing the same under SATA III

I dont have access to Sata-3.
250mb/s will be good for SATA 2, I know this and don´t expect higher performance.
What I still expect ist gettting under Win 7 the same read/write performance like under XP.

Could the bad Win7 performance with yours SSD perhaps be driver related?
I ask this, because my XP uses SATA chipset drivers from AMD, whereas my Win7 uses the Microsoft stock drivers.

In XP,  the Device Manager looks like this:

AMD PCI IDE Controller

AMD SATA Controller

The Win7 Device Manager still says:

Standart 2channel PCI-IDE controller

Could perhaps this Microsoft standart IDE/stock driver be the bottleneck?
If yes, what AMD Sata/chipset Win7 64bit driver do you recommend for yours Sandisk Plus in combination with 790 chipset based boards (SB 750)?

Hi Petex,

Yes driver may be related to performance, unfortunately we don’t have a recommended driver level for your situation 

The driver is not for the SSD it is for the SATA chipset on the MB. Best place to look for the drive will be the MB manufactures webpage. If you can let us know what the MB make and model is we can see if we can find the latest SATA driver for it. 

it is a Biostar 790GX Xe, the driver on the Biostar page is rather old and outdated, but I found on the AMD website the latest SATA + SB driver (from 2015/16).

I also found the reason for the bad seq. write rates:
It seems the Panda Antivirus software interferes a lot with the Sandisk performance.
The Intel SSD losts around 35mb/s seq. write performance if Panda is ON, whereas the Sandisk losts over 110mb/s.
This huge performance drop is strange:

However, but even if Panda and everything is turned OFF --> 4k 64thrd performance remains poorly.
The old Intel SSD outperforms the Sandisk in nearly all cases.

The most annoying thing:
Yesterday, I booted XP (installed on the Intel), and it crashes some datas (indizes) on the (Win7) Sandisk.
Win7 (installed on the Sandisk) wont boot anymore and have to restore.
I dont know what is wrong with this SSD, never had such hassle with any data lost bevore. :neutral_face:
Very frustrating and it cant be worster.
Obvisiously I should better buy a SSD from another company and replace asap this Sandisk Plus. 

Hi Petex,

Please contact our support center so we can have more detailed analysis and better assist you

jhelp you out here.

AMD old SB 7xx chipsets suck for SSD performance

Often the windows generic is better. Otherwise, backtroll to the vista driver, which performs better. Going to the Vista driver has one advantage: performances go up. Howrever, you often loose the smart data reading since it considers your controller as raid.

Benchmark shold be done as a secondary drive unit, or with all antivirus off, and with minimum services running in the background. Your sequential numbers look ok anbd these variatons are likely due to antivirus/services interfering, but where you will see a big difference regarding the driver for the SB controller, are the 4K results :wink:

Unfortunatly, I wasnt able to find any old Vista driver (for Win7?).
Yesterday I finally putted the old 120GB Sandisk back to my PC. I have also not contacted the customer support, because if the offical forum has no solution - I guess, the customer support will also not work out anyhting.

Well, I benched now again and
my 120GB Sandisk has nearly 2x times higher 4k 64thrd write rates and outperforms the 240GB version in all write tests.
The old AMD chipset may be not the fastest, but 200-260mb/s seq. read/write is fine for SATA 2 and aso keep in mind , the Intel & 120GB Sandisk perform like it should be.

Since we dont know what controller is inside this 240GB Sandisk, who knows - perhaps there are versions with  fast/good controllers and perhaps also slow version around with cheap controllers?
I dont know, I still know:  This 240GB drive is for some reasons slower then the 120GB version.

So, I decided to use the Sandisk just only as storage and XP cache drive (Eboostr) for my HDD.  Since there is no XP trim tool, I will boot the SSD as secondary drive from time to time into Win7, so it should also get some trim.