Slow Transfer between WD6401AALS & WD1002FAEX


#1

Hi I have 3 WD1002FAEX set as raid 5 and 2 WD6401AALS as raid 0.

When I do a drive test on them (using hdd tach) the average read rate is raid 0= 223 MB/S and the raid 5=127mb/s.

The problem I have is when I transfer files from the raid 0 to my storage drive raid 5 it starts off at 200mb/s and slowly makes its way down to a sustained  23mb/s.

Could this problem be due to the interfaces being different ie 3gb/s to 6gb/s?

The raid 5 is set as GUID format and the raid 0 as MBR format, could this cause the problem?

Note: I was running the caviar greens in raid 5 before i replaced them with the caviar black 1tb and it would sustain 80mb/s tranfers with the greens.

Thankyou. any help is much appriciated.

Just for reference:

WD1002FAEX = 1tb, 64mb cache, 6gb/s sata, caviar black.

WD6401AALS= 640mb, 32mb cache, 3gb/s sata, caviar black 

My system:

i7 @ 4ghz

asus rampage ii extreme

6gb ram

2x 4870x2


#2

hardware or software raid?

perhaps bad cable(s)?


#3

The raid driver i’m using is the one built on the mb (intel matrix).

Replaced the cables but problem still there.


#4

Fix the problem.

Had to go into the intel matrix and enable cache write back. 

Now transfer at 123mb/s :slight_smile: