PERC 6/i Slower than onboard? - Overclock.net

OpTiMaTeZ · 12-31-09

I recently got 4 SSD's (OCZ Vertex's) that can go around 230 read. Individually, i have tested that they are able to do this. Then i put them in all sorts of combinations on my motherboard in raid 0 and never could get them to go faster than 200 with all 4 combined. After much appreciated help from overclock.net users i came to the conclusion that my nvidia chip set was limiting me. Thus, i bought a perc 6/i from burito and i just got everything installed and windows up and running. However, now i have several problems as listed below:

1) I cant use the onboard and Perc Raid controller together - It gives me an error message that says " Option rom can not be invoke" and a vendor/device id at the end. I looked it up and it says that is something to do with there not being enough memory. I will have to buy another cable to use just the PERC, which i would like to avoid. And temporarily i have found that i can just boot to windows and then plug in my old harddrives with my data and it will recognize them and let me access the files. Is there a way to resolve the error message? Buying another cable will be difficult because i have SLI and the SLI bridge goes over the first cable input and i dont know how i would get them to fit, and i am using the second cable input for the SSD's.

2) They are slower than onboard! With the onboard raid the 4SSD's got around 170read, now they are only getting around 120!!! I set the stripe size to 128 and gave it a fresh install of windows 7 ultimate 64bit and its still going much slower than the 400-500+ read speeds i was hoping for. Does anyone have any ideas why it is going so slow? Would really like to get these 4 SSD's running as fast as possible...

3) What am i doing wrong?! any insight on how to fix this = +rep

ImmortalKenny · 12-31-09

Do you have writeback enabled on the SSD's?

OpTiMaTeZ · 12-31-09

Where would i check to see?

ImmortalKenny · 12-31-09

EDIT: Nevermind.

OpTiMaTeZ · 12-31-09

I have an nvidia chipset, and a perc 6/i card from dell. i dont think i have an intel raid manager

ImmortalKenny · 12-31-09

Sorry, I don't know what I was thinking.

Lol, it would probably be in the Perc's software.

OpTiMaTeZ · 12-31-09

for read policy, i have no read ahead, however the options are read ahead, no read ahead, and adaptive read ahead. The write policy is set to Write Through, the other option is write back. So i am assuming I do not have write back enabled as i have Write through enabled.

What should these settings be?

ComGuards · 12-31-09

# Read-Ahead. When using read-ahead policy, the controller reads sequential sectors of the logical drive when seeking data. Read-ahead policy may improve system performance if the data is actually written to sequential sectors of the logical drive.

# No-Read-Ahead. Selecting no-read-ahead policy indicates that the controller should not use read-ahead policy.

# Adaptive Read-Ahead. When using adaptive read-ahead policy, the controller initiates read-ahead only if the two most recent read requests accessed sequential sectors of the disk. If subsequent read requests access random sectors of the disk, the controller reverts to no-read-ahead policy. The controller continues to evaluate whether read requests are accessing sequential sectors of the disk, and can initiate read-ahead if necessary.

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Note: Storage Management does not allow you to select the Write-Back policy for controllers that do not have a battery. This restriction protects a controller without a battery from the data loss that may occur in the event of a power failure. On some controllers, the Write-Back policy may be available in the controller BIOS even though it is not available in Storage Management.

* Write-Back. When using write-back caching, the controller sends a write-request completion signal as soon as the data is in the controller cache but has not yet been written to disk. Write-back caching may provide improved performance since subsequent read requests can more quickly retrieve data from the controller cache than they could from the disk. Write-back caching also entails a data security risk, however, since a system failure could prevent the data from being written to disk even though the controller has sent a write-request completion signal. In this case, data may be lost. Other applications may also experience problems when taking actions that assume the data is available on the disk.

* Write-Through. When using write-through caching, the controller sends a write-request completion signal only after the data is written to the disk. Write-through caching provides better data security than write-back caching, since the system assumes the data is available only after it has been safely written to the disk.

OpTiMaTeZ · 12-31-09

I just enabled write back and read ahead, ill see how it changes performance.

OpTiMaTeZ · 12-31-09

it improved my performance by about 10MB/s. Now it is around 130MB/s. But i am still looking for 400-500MB/s with 4 SSD's. Also, it appears that it doesnt think the battery is plugged in, yet it is. And also during boot when the perc 6/i is loading, it takes around 30 seconds. This is longer than the rest of the boot to windows put together, is that normal? Thanks.

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PERC 6/i Slower than onboard?

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