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allyn

New build / PCI-E bandwidth issues?

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ok, finally got all parts in and did the build. everything is going decently, but my array performance is not up to snuff for some odd reason...

 

rough specs:

opteron dual core 1.8 ghz

evga 7800gt

promise 8350 8 port pcie sata controller

2x 74 gb wd raptors

6x 400 gb wd re

 

build pics:

 

here.

 

after coming to the realization that my ocz 2gb of ram absolutely refused to work properly with the board, and even after trying these settings, i threw in the towel and put in a 512mb stick of kingston. I'll worry about the other ram later.

 

Then i went through a fiasco where the windows install kept restarting from the cd after every reboot (i.e. after the first file copy). I finally gave up on the on-board raid controllers and moved the pair of raptors over to the promise board - with the other 6 drives.

 

ok, now for the fun. I got into windows, using all recent firmware and drivers. I had set up the other 6 drives (6x400) as raid-5. I fired up hdtach and this is what i saw:

 

2tb-r5-s.png

 

which seemed kind of odd to me. i thought perhaps raid-5 might be taxing the controller, so i switched the array over to raid-0:

 

2tb-r0-s.png

 

hmm, same result, but the speed seems to be bouncing around at a different rate this time.

 

I then dug around online and found some benchmarks that were very similar to my setup (same card / motherboard). Check out entry 1 and 4 on that chart (click the right column for the hdtach output). Those guys are hitting 450 meg/sec burst speed, not to mention the much faster transfer from the drives. those benches were done with stripe size of 64k, which matched my choice.

 

so... i figured it had to do with my setup, so i tried the following:

 

- switching to/from sli mode (8-4-N-8 / 2-1-1-16)

- moving the controller to various slots (8x / 4x)

- reinstalling xp with no other drivers except the promise controller

- installing vista beta 64 bit version

- disabling all possible extras in the bios

- varying PCIE bus speed (100/105/110)

 

every one of the above gave the exact same results. something is capping the transfers to about 150meg/sec burst and 100meg/sec sustained. I got very similar results from the raid-0 stripe of my pair of raptors.

 

so... im stumped. any suggestions on what else i can check? I really don't get why my bench is nowhere near what those other guys are getting with the same hardware...

 

TIA for any assistance

Al

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Hello allyn,

 

unfortunately I do not know much about the promise RAID controller (I use the areca), but did you check the following:

 

- is SATA300+NCQ transfer mode for the connected drives enabled?

- is read/write cache for the connected drives enabled?

- is read/write cache on the controller enabled?

 

ChriZ

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ok, i went through the promise array mgmt utility stuff. the write cache was disabled for the 400 drives, but enabled for the 72 gig drives. i enabled the write cache for the 400's and reperformed the test with the same result. controller cache was already enabled, and there are no sata/300/ncq options that i could fine (and they shouldnt really impact a sequential read test from 6 drives, anyhow). I then recreated the raid-0 with 32 vs. 64 kb stripes:

 

2tb-r0-s-32.PNG

 

smoother transfer, but still the same limit. it really has me stumped...

Al

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Try a smaller stripe and you'll see hdtach shine...

 

Try other approach to benchmark, like everest disk benchmark.

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Try a smaller stripe and you'll see hdtach shine...

 

Try other approach to benchmark, like everest disk benchmark.

 

32 kbyte stripes is the smallest i can select with the PAM software. Also, changing from 64 to 32 only smoothed out the line, and had no impact on burst speeds. BTW, burst has nothing to do with stripe size - it indicates how fast the controller is communicating with the motherboard. I strongly suspect that if i find the cause of the burst speed being so low, the rest will fall into place. here is what this setup should be doing:

 

promiser08x0zp.jpg

 

promr04xrapt5ps.jpg

 

Notice the significantly higher burst speed - this is to be expected with PCIE, but its just not happening here for some odd reason.

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Hey I wish I could help but I dont really understand what all that means. Can someone educate me? lol, the RAID drivers are for your raptor sata hdds, but I dont understand what that HD TACH is showing.

 

Thanks,

Mako3

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Hey I wish I could help but I dont really understand what all that means. Can someone educate me? lol, the RAID drivers are for your raptor sata hdds, but I dont understand what that HD TACH is showing.

 

Thanks,

Mako3

 

the raid drivers are actually for the raid card, which is an 8 port promise card. windows is on the 2 raptors, while the benchmarks are being ran on an array of 6 400 gig drives, which are also on that controller. there are no drivers for any particular drive, just the raid controller. this is similar to what happens when you use on-board raid, as you have to do the "F6" thing during windows install and use a driver disk.

 

Al

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Alright thanks Al, I sort of understand. Im look at the sx8300, I've never heard of a promise card before. What was HD Tach showing in those readings though?

 

-Mako3

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Alright thanks Al, I sort of understand. Im look at the sx8300, I've never heard of a promise card before. What was HD Tach showing in those readings though?

 

-Mako3

 

the graph along the top is the data transfer rate from start to end of the array/drive. the bottom left shows the burst transfer rate to the controller/drive. with an add-on raid controller, burst rate will depend on the interface from motherboard to controller. with a single hard drive, burst rate will indicate the transfer rate of the drives interface itself (i.e. 150 meg/sec or 300 meg/sec for sata).

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@allyn

 

Go ahead and update your sig to reflect the rig you're working with. It makes it much easier to see what you're dealing with and it is part of the forum rules.

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@allyn

 

Go ahead and update your sig to reflect the rig you're working with. It makes it much easier to see what you're dealing with and it is part of the forum rules.

 

if i cant get this board/controller combo above 100meg/sec, my "new sig" will be very short lived :). Besides, my current rig remains the PC-DL, and i'm swapping hardware (ram, etc) around so much in the DFI rig that updating the sig will likely confuse more than help...

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Check the driver version for the Promise card. A buddy of mine had to update the drivers to resolve his bandwidth problem.

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