2 or 3 raptors?

arfur said:
I noticed that when I forced it to 1G 1.5Gb/s the read score stayed the same but the burst went down so its like it cant read faster than 1G
Click to expand...
That's to be expected, the HDD can't transfer data at a sustained rate anything like the 150Mb/s available to each channel in SATA1 (1.5Gbps) mode. The drive however can use the available bandwidth in burst mode when the data is just coming from the cache so you will see the burst rate drop when changing from SATA2 to SATA1 mode.
 
yep, thats how I understand it but the 120Mb/s in RAID 0 is still a major problem, 2 disks should reach that (ish)...
 
i've tried 16k, 64k and 128k, its currently on 128k (nvidia optimal).

what would you expect to get out of these drives?
 
128K won't give the greatest benchmark scores but they shouldn't be hugely wide of the mark.

I get about 115Mb/s out of 2 7200.10s and that's lower than it should be. I'd like to think that 3 should give you approaching 200Mb/s but I've not seen anyone else running a 3 disk array so I don't know what is possible.
 
I'll change the stripe to 16k and see what happens or do you think this is too low? I mainly use it for gaming,
 
just reinstalling XP on 2 seagates as a test, but my 2 spinpoints in RAID 0 get 119Mb/s and that 2 disks and on the same controller....maybe its something to do with an odd number of disks... we'll see
 
i have now got the 3 drives giving a constant 133mb/s, in HD Tach the graph is pretty flat all the way across, I disabled all caching on the 3 Nvidia raid controllers and disabled NCQ, this seemed to cause the most slow down. On 2 drives I was getting 120Mb/s so the 3rd drive hasnt given that much. the graph doesnt breach 135Mb/s any more ideas as to why?

thanks
 
I suspect the bottleneck is elsewhere - I'm running a 3 disk array of 3x18Gb 15k3 scsi cheetahs on the Dell perc 4/e (LSI 320 2e) and that 'only' gets 150mb/s.

Not sure you're going to see much more than what you have at present - the fact that the graph is 'flat-lined' normally indicates a controller limit - certainly what I saw when I was on my old Pci-x card in a pci slot and maxed out the bandwidth!
 
From Wiki - knew I'd seen it somewhere:

First-generation SATA interfaces, also known as SATA/150 or SATA 1, run at 1.5 gigabits per second (Gbit/s). Serial ATA uses 8B/10B encoding at the physical layer. This encoding scheme has an efficiency of 80%, resulting in an actual data transfer rate of 1.2 Gbit/s, or 150 megabytes per second (MB/s) (or 146.48 MiB/s). The relative simplicity of a serial link and the use of LVDS allow both the use of longer drive cables and an easier transition path to higher speeds.
Click to expand...

Sata 1 max theoretical is therefore just less than 150mb/s - so not too bad - not sure what your controller is though?
 
its a brand new Asus 680i chipset, its capable of SATA2 speed. I thought each port was capable of 150Mb/s I'm not getting that with 3 ports in use, so each port is only getting about 45Mb/s instead of the 150Mb/s.

I have had the same problem on 3 different controllers, gigabyte, intel Matrix and this Nforce one.
 
You must log in or register to reply here.
Back
Top Bottom