Question SSD Performance Changes Depending on Which SATA Port is Used


Jan 2, 2014
I have a desktop with 6 internal hard drives (1TB Evo 840 system SSD, 2 - 4TB Evo 860 data SSDs, 2 - 8TB HDD Backup Drives for Data SSDs, 1 - 4TB HDD Backup Drive for System SSD. System specs below.

As the title says, I get different performance levels for the identical 4TB Evo 860s depending on which SATA ports on the motherboard they're hooked up to. I just recently ran Samsung Magician's performance tests on the two 860 drives and the one on F: had roughly 66% the performance of the 860 on E:. I swapped the connector from my 8TB HDD on H: to the 860 on F: and performance got another 10% worse. I then took the connector from the 860 on E: (rendering it offline) and hooked it up to the 860 on F: and the drive now had the same performance that E: used to have. In other words, it recovered the 33% performance hit.

I next reconnected the 860 on E: and swapped the SATA connector to my optical drive D: (taking it offline) and hooking it up to the 860 F:. That brought performance on F: to around 95% of E:, which is good enough for me and how I've left it.

Still, can anyone explain whether this behavior is normal or if I need to change something in my configuration to gain the same level of performance on drives no mater which SATA port they are connected to. System info follows:

OS Name Microsoft Windows 10 Pro
Version 10.0.18362 Build 18362
Other OS Description Not Available
OS Manufacturer Microsoft Corporation
System Manufacturer MSI
System Model MS-7845
System Type x64-based PC
System SKU To be filled by O.E.M.
Processor Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz, 4001 Mhz, 4 Core(s), 8 Logical Processor(s)
BIOS Version/Date American Megatrends Inc. V1.12, 2015-05-19
SMBIOS Version 2.8
Embedded Controller Version 255.255
BaseBoard Manufacturer MSI
BaseBoard Product Z87-GD65 GAMING (MS-7845)
BaseBoard Version 1.0
Platform Role Desktop
Secure Boot State Off
PCR7 Configuration Binding Not Possible
Windows Directory C:\WINDOWS
System Directory C:\WINDOWS\system32
Boot Device \Device\HarddiskVolume6
Locale United States
Hardware Abstraction Layer Version = "10.0.18362.267"
Time Zone Central Daylight Time
Installed Physical Memory (RAM) 32.0 GB
Total Physical Memory 31.9 GB
Available Physical Memory 23.8 GB
Total Virtual Memory 32.1 GB
Available Virtual Memory 22.3 GB
Page File Space 200 MB
Page File C:\pagefile.sys
Kernel DMA Protection Off
Virtualization-based security Not enabled
Device Encryption Support Reasons for failed automatic device encryption: TPM is not usable, PCR7 binding is not supported, Hardware Security Test Interface failed and device is not Modern Standby, Un-allowed DMA capable bus/device(s) detected, Disabled by policy, TPM is not usable
Hyper-V - VM Monitor Mode Extensions Yes
Hyper-V - Second Level Address Translation Extensions Yes
Hyper-V - Virtualization Enabled in Firmware Yes
Hyper-V - Data Execution Protection Yes


Mar 16, 2013

On-Board SATA

SATAIII controller integrated in Intel® Z87 chipset
- 1 x mSATA 6Gb/s port*
- Supports six SATAIII ports (SATA1~6) by Z87
- Up to 6Gb/s transfer speed.

• SATAIII controller integrated in ASMedia® ASM1061 chipset
- Up to 6Gb/s transfer speed.
- Supports two SATA ports (SATA7~8) by ASM1061


Even though the ASMedia ports say "6Gb/s", they are decidedly slower.
Presumably you're seeing this slow down in the SATA 7 & 8 ports?
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