cancel
Showing results for 
Search instead for 
Did you mean: 

IDE-AHCI-RAID... so far

idata
Esteemed Contributor III

When I start my bios i can choose how to set up my SSD: AHCI,IDE,RAID

AHCI and IDE are similar (AHCI newer and more advanced, IDE more standard and compatible) AHCI, I guess, support the automatic TRIM in window7 while IDE don't but i am not sure about this...

RAID has two possibilities:

a) single SSD

Doesn't support automatic TRIM but support the TOOLBOX (correct me if wrong)

b) With RAID-0 SSD (2xSSD disk)

Doesn't support anything but go faster ^_^ (there is any way to trim or clean the empty space with this configuration?)

This said if you have just one SSD which one would you advice?

AHCI?

IDE?

RAID-mono disk?

26 REPLIES 26

idata
Esteemed Contributor III

I believe the short answer to whether you can transfer a system disk image from a disk operationg under Raid mode to a second disk that will be operating under AHCI mode--and expect it to boot and run Windows--is no. The extended answer is that the disk driver for a boot disk is embedded in the startup process for Windows and cannot be changed on the fly at boot time. Result: Blue Screen.

There are other reasons not to do this, even if it would work. First, the exact location of partitions on SSDs is important for max performance. The hard disk may not have the optimal layout, and that layout will be part of the image. Next, It is desirable to minimize wasted space on SSDs because the total space is so limited. Functions that are not going to be used--but that can be added later to Windows--should be removed from the SSD ASAP. Some of these are the hibernate file (same size as your memory) and the page file (usually do not need this if 64 bit and you have 6 or more GB of memory). Also the system restore file can be cut back in size considerably. I have reduced a 17GB new install of Win7x64 down to 5GB using these three techniques. And last, nothing beats a clean install on a freshly wiped SSD.

I did a bit of further testing with the U3S6. I pulled the board from the original test system and installed it into a system operating in Raid mode, with two SSDs in a Raid 0 array and one HDD in non-raid attached to the motherboard Raid controller. Then the working AHCI disk from the original system was connected to the U3S6, the boot order was set to boot from the U3S6-connected disk, and the system started up, loaded all the drivers for the Raid system, and runs smoothly. I also loaded the Marvell and NEC drivers for the U3S6 controllers.

Here is Device Manager for this setup.--

You can see the U3S6 items toward the top of the list, and the default Raid drivers for the onboard Sata controllers near the center. There is a DVD in addition to the disks under the Raid controller.

Here are more test results--

The pic above shows the same (as in my last post) 80GB Intel G1 disk operating through the U3S6 controller, using the Marvell driver, and co-existing with a Raid controller for the onboard Sata ports. AS SSD has "SCSI Disk" in its description, which might be read to indicate that a disk under the Marvell controller will not be eligible for TRIM or for using the Intel SSD Toolbox; cannot answer that yet. In any case, the Marvell controller is not necessary, and the disk will display as AHCI without it.

For a further point of reference, here are AS SSD results for the SSD Raid array using the default Win7 driver, and tested from the OS on the U3S6--

The second test is a previous run on the SSD Raid array using the RST driver. You can see the that RST driver bumps up the write performance, while knocking down the read performance a bit.

Here is an HD Tune test of sequential reads at various block sizes--

Here you see the array reaching full write speed at block size of 2KB, with read speed always exceeding write speed.

And, finally an HD Tune test of random access reads at various block sizes--

Note, at the 4KB block size, the serious disagreement with AS SSD.

Well, I strayed off topic. Do a fresh install on your SSD. If the SSD has anything at all written to it, first run a simple secure erase with HDDErase 3.3.

GCatt
New Contributor

Thanks, Einride. I was afraid I would need to do a Windows re-install to move my boot disk from RAID to AHCI. Not sure if I want to do that, as there are many applications that would need to be reinstalled and configured. I don't think the wife would be happy, as she uses this machine every day. I think I'll wait for Intel to support TRIM in their RST drivers and then go for a G2 Intel SSD and run it in RAID mode. Also, I'm sure Intel's drivers will be a better choice for optimal performance on an Intel SSD. I've already tested an image restore of my boot disk using Norton Ghost, and it works great. Partition offsets are restored to their original settings, which I've already verified as optimal for a SSD.