The Marvell 9128 SATA controller is the main source of your performance issues. I am familiar with the limitations of the Marvell 91xx series chipsets, as is the SSD enthusiast community. The main one is it is connected to, and can only work with, one PCIe lane. That limits it to at best 5Gb/s (yes Five) rather than the full 6Gb/s speed of a true SATA III interface. That one PCIe lane is also shared between the two SATA ports the Marvell chipset provides on mother boards, or add-on PCIe cards, there is no difference between the two. I'm guessing that you may have two drives connected to the Marvell SATA ports, which might further limit your sequential read speed performance, which at best is no more than ~400MB/s on the Marvell chipsets, even with one drive.
But you also mentioned the "PCIIDE -BAD" display in AS SSD, which has proven to be accurate in all cases. Your installation in AHCI mode was likely done with the Intel chipset on your board. The SATA mode setting is separate for each chipset, and each must be set to AHCI or RAID independently. You'll need to check which driver you have installed on the Marvell chipset, in Device Manager under Storage Controllers, or IDE ATA/ATAPI controllers. In IDE mode you won't get the performance boost that Native Command Queuing (NCQ) provides, which is only available in AHCI or RAID mode. That would account for your sequential read speed being below 300MB/s even on the Marvell chipset.
The only current chipsets that provide the best SATA 6Gb/s performance are the Intel 6 and 7 series chipsets, and some AMD chipsets, although the Intel chips are recognized as being the best in SATA III performance. There are some separate RAID cards that perform at that level too, but they cost at least as much as your mother board, and usually much more than that.
Your problems with the Toolbox are also caused by the Marvell chipset, which I can guess is using the Marvell driver, in IDE mode. The Marvell chipset and Marvell driver combination is not compatible with the Toolbox in most if not all cases.
The best fix you can perform is to enable AHCI mode on the Marvell chipset specifically, and use the native Windows 7 AHCI driver, msahci. That can be done in Device Manager, with a manual driver update. The Standard AHCI driver will appear in the list of drivers you can use with the Marvell chipset, and for most users provides the best performance. Once updated, the Marvell chipset will no longer be called that in Windows, or listed under Storage Controllers. It will appear in the IDE ATA/ATAPI controller list.
That is how I use the Marvell chipset on the boards I use that have it. I can run the Optimizer on other Intel SSDs in that configuration, but have never used 520 SSDs on that interface, so it might not work with them. The 520 will work fine with the Toolbox on the Intel SATA II ports.
You may find, as others do with X58 mother boards, that using your 520 on the Intel SATA II ports overall works better than the Marvell chipsets. The sequential read speed in benchmarks is better on the Marvell chipset, but the Intel SATA II interface is superior in all other areas, given it is used in AHCI or RAID mode, with a current IRST driver. Sequential read speed is not the most important aspect of a drives performance if it is an OS driver.
If you Google on Marvell 9128, you'll find posts like yours and mine all over SSD and mother board forums. Welcome to the marvelous Marvell chipset club, there are many of us out there!
Yes, indeed, I didn't set AHCII for marvell chipset. The setting was "hidden" somewhere else in bios (could have at least put it in the same section). Speeds are a bit better now:
I didn't install any drivers yet, so it has to be the default win 7 driver, which is the best in your opinion...
However, this is still far far below 5Gb/s, which is the limit for Marvell controller and I am very disappointed.
I also found out that Intel Rapid Storage Technology driver is actually for Intel Sata II controller and had no effect on "Sata III" port performance anyway.
There are some new firmware/software updates for Marvell controller which came out this month... will prolly give it a try soon.
So... does any1 else have some suggestions?
PS: TRIM and SSD Toolbox are working fine now...
5Gb/s (lower case b) means 5 Giga-bits per second, not Bytes. Just as the true SATA III spec of 6 Giga-bits per second refers to bits, not bytes. Bytes are 'B', bits are 'b', in the standard abbreviations. Every byte is composed of eight bits, which is a standard written in digital stone.
The maximum theoretical performance of a SATA 6Gb/s interface is 600 Mega-Bytes per second. But, since the SATA interface, by specification, transfers 10 bits for every 8 bits of data, plus other overhead and other real world limitations, the real world maximum speed becomes about 500 Mega-Bytes per second, for large file, sequential read speed. That of course assumes that the SSD is not doing any other work, and the PC is mainly working on the SSDs reading of a file.
Everything in my first post stands, about the Marvell SATA controller, the non-compressible data thing, etc, sorry to say. You can try another brand of SSD if you like, but it won't make any difference. As I said before, Google on "Marvell 9128", and tell me what you find.