Comparison of IOCrest SI-PEX40071 SATA III Controller with onboard Intel RST SATA II

System Requirements:

  • A free PCIe 4x slot
  • IOCrest SI-PEX40071

The Problem:

This came about, not because I needed or intended to bench mark the controller, but because I had a large number of 1TB drives that I wanted to string together into a Dynamic Disk Volume and didn’t have enough ports on a motherboard to connect all of the drives up.

The cheapest solution that I could find was the £45 IOCREST 8 Channel PCI-Express Serial ATA Host Controller Card a non-RAID HBA for up to 8 SATA III drives. Model number SI-PEX40071.

The controller is a cheap 8 port SATA III interface running on a Marvel Chipset. The device uses a PCIe 4x slot and presents two controllers to the system bus, not one. This is significant as it a) means that it requires special IOCrest drivers to permit Windows to see the second controller and b) means that only the disks on the first controller, i.e. ports 0-3 are presented to the BIOS.

Please keep that in mind if you need boot support! It can boot from the controller on BIOS or UEFI if the interface is attached to port 0-3.

As I had it and before I put it to use in the dynamic disk, I thought that it would be interesting to see what sort of a difference it would make to a system that only shipped with SATA II on the motherboard. While rotational hard drives cannot saturate a SATA II bus, let alone SATA III. A SSD might come close and consequently SATA III + a SSD in a PCIe 8x slot (with boot support) would seem like a way to achieve higher transfer speeds.

More Info

I did not have long to test it, so I only performed some rudimentary testing.

The test compared a Samsung 840 Pro 250GB SSD running on Port 0 of the IOCrest controller vs. Port 0 of an Intel STA II controller on a X58 chipset running in AHCI mode. In all three tests the same SSD was running with the write cache enabled and cache control set to write back i.e. optimal. All tests were performed on Windows 10 Enterprise and the SSD was the boot drive and the only drive present in the system.

The IOCrest controller was tested twice, one batch with the Microsoft Windows 10 default Marvel driver (only ports 0-3 working) and the second batch with the latest driver from IOCrest (not an actual Windows 10 driver and in actual fact fairly old at late 2012).

Testing was performed 3 times for each test with the data being generated by the latest version of Samsung Magician. The mean of the three runs is presented in the table below.

Sequential Read (MB/s)
Sequential Write (MB/S)
Random Read (IOPS)
Random Write (IOPS)
Intel RST SATA II (Microsoft)
IOCrest SATA III (Microsoft)
IOCrest SATA III (IoCrest)

In all cases higher values are preferable.

The onboard Intel storage controller running in AHCI mode out performed the SATA III PCIe controller by a considerable margin. 70MB/s on read and 100MB/s on write! These values aren’t even close.

Simply put, cheap controllers – especially ones labeled SATA III – are a false economy. I wouldn’t have expected to see something close to enterprise level hardware, however I was expecting to see something that offered at the very least moderate performance increase over a SATA II controller.

The sad thing is that using this controller, Samsung Magician stops complaining that it is running on a SATA II controller, citing the SATA III controllers presence as meaning that it is running optimally even though its performance has been frankly nothing short of crippled.