HD tach - 2 x 150gb raptors in raid0

ByteJuggler · 7 Jan 2007 at 16:56

malcolm said:
The Raptors are only SATA 1 drives. They get close to the theoretical limit for SATA1 because they spin at 10,000 rpm.

Umm, well, not quite.

I'd say a Raptor by itself does not actually get nearly close to the limit of SATA 1, a single raptor doing about 75Mb/Sec or so sustained at its best, and SATA1 spec being 150Mb/sec, apart from when it's bursting from its cache of course. So unless you consider 50ish percent usage of available bandwidth "close" then in my book it ain't. :-)

(In fact, the Seagate 7200.10's beat the Raptor's by a small margin on the faster parts of the 7200.10 platters, so they get marginally "closer" to the SATA 150 limit though of course nowhere close either, but I digress.)

Secondly, when in RAID 0, each raptor has a seperate channel going to the controller, so each has its own pipe that will carry up to 150Mb/sec, so the total combined bandwidth is therefore 300Mb/sec. Thus, when the RAID0 array transfers data the limit is actually 300Mb/sec. This can be seen in the benchmarks, when you look at the burst speed, which exceeds a single channel's 150Mb/sec. The fact that 2 raptor's in RAID0 zero outputs approximately 140-150Mb/sec sustained, is thus simply down to how fast they each are individually (70-75Mb/sec * 2), and has nothing to do with the SATA 150Mb/sec limit applicable to a single SATA channel running in "SATA I" mode.

Anyway... I'm too much of pedant sometimes...

ByteJuggler · 7 Jan 2007 at 17:36

jbloggs said:
2 x 74GB Raptors (8MB cache) in RAID0 (32KB stripe, 4KB cluster) on ICH7R con. (long bench 32MB):
Click image to enlarge.

OK, 2 x 74GB Raptors (8Mb cache, nearly 3 years old now) in RAID 0 (16KB stripe, IIRC) on Via 8237 controller (long bench 32MB), on my old ASUS K8V based 754Pin 3200+ Clawhammer:

iMacMart · 7 Jan 2007 at 18:02

Setting up 2 x Seagate 7200.10 250gb drives this week on RAID 0 whats the best kb for gaming and general OS ??

16kb or 32kb?

Cheers

jbloggs · 7 Jan 2007 at 22:19

tweakinfreak:

32KB.

BeelzebubUK · 8 Jan 2007 at 08:08

BeelzebubUK said:
This is my 2x 150GB Raptors in RAID 0 using the 32Mb test on a fairly fresh install of Windows XP SP2 on the Intel controller of the Asus P5W DH deluxe :

Looks like yours could still do with improvement but its probably not really noticeable compared to mine as its fairly close.

Should mine look a lot different though ?

Same system but I've changed the stripe size from 128k down to 32k now :

Very different on the graph and its boosted the average read speed by 20MB/s.

ByteJuggler · 8 Jan 2007 at 18:24

BeelzebubUK said:
Same system but I've changed the stripe size from 128k down to 32k now :
20MB/s.

Now *that* is smokin...

jaykay · 8 Jan 2007 at 18:45

hole crap 155mb average :eek:

iwant 2 of them

james32 · 8 Jan 2007 at 19:36

my 2 scsi 15krpm maxtor atlas only gets 169 with a 64kb stripe

eiko_magami · 13 Jan 2007 at 01:16

pair of 15k drives should look something like this

mosfet · 13 Jan 2007 at 15:02

That's absolutely insane, although if you pay that kind of money you expect performance to equal.

I've got 6 Seagate Cheetahs sitting a box here but no controller to put them on. Once, just once, I'd love to have them all in a RAID0 setup and do some benchmarks.

james32 · 13 Jan 2007 at 15:10

eiko_magami said:
pair of 15k drives should look something like this[/QUOTE]

thats SAS drives, and theirs no way 2 SAS 15k drives can hit that
your max drive rate is 147 MB/s x 2 = 294

think hd tach is not accurate with your SAS card and drives

what cluster size and stripe are you using?

Jokester · 13 Jan 2007 at 15:13

2 Spinpoints in RAID 0 (128k stripe) on a 680i chipset controller.

Jokester

eiko_magami · 13 Jan 2007 at 17:14

4k cluster 16k stripe im also thinking its a little wrong after doing more than running it and posting. access time looks very low to

NachT · 14 Jan 2007 at 00:35

My 2x 150 GB Raptors in RAID 0

Lol ^_<

Spent days trying to fix it, when i e-mailed the company who make my RAId controller they just said that it must be HD Tach not giving the right results, don't know if thats true tho.

BeelzebubUK · 14 Jan 2007 at 13:40

Something seriously wrong with that.

if they're so sure that its HDTach ask them what they use to bench test their card

Strange that it doesn't drop off at the end of the drives like most of the others. Looks like there is definitely something throttling the bandwidth rather than the drives themselves.

NachT · 14 Jan 2007 at 14:54

Yeah they give me another program to bench them on, but got the same results with that.

If those results are real then, must be my motherboard thats giving me bad results. The board I have is a terrible board, so maybe.

Jokester · 14 Jan 2007 at 15:04

Try disabling Read Caching in Device Manager for your SATA ports.

Jokester

ByteJuggler · 14 Jan 2007 at 15:36

NachT said:
Yeah they give me another program to bench them on, but got the same results with that.

If those results are real then, must be my motherboard thats giving me bad results. The board I have is a terrible board, so maybe.

Yeah that looks like some sort of bus bottleneck somewhere. Normally PCI's peak practical sustained transfer is around 110-125Mb/sec (of a theoretical 133Mb/sec.) So if it's PCI that's throttling you then yeah, the board is seriously crap or there's something wrong. Are you sure the bus is not underclocked somehow? I really find it hard to believe that even the crappest PCI chipset today will be that slow (of course, anything is possible lol...) What PIO modes are the drives running at? Is tha cables in good nick?

NachT · 14 Jan 2007 at 15:36

These are the only options I have,

I've tryed everything, and nothing works. I might be upgrading soon, so a new motherboard should fix it.

Jokester · 14 Jan 2007 at 15:38

What type of socket does your card use?

Jokester