X99/C610 motherboard's all SATA port total speed only reach 1.2GB/s write with 1.6GB/s read
I have been entangling this issue for a few days and searching online didn't find any explainsion. I use one CPU E5 2678 v3 on the Huananzhi X99-AD3 motherboard. I connected ten disks. When I test the speed for all the 10 SATA ports, the speed is quite slow. It can't reach DMI 2.0's maxium 2GB/s.
The test result is on Window, the total write speed is around 1.1GB/s and read speed is 1.6GB/s.
While on linux, the total write speed is around 1.2GB/s and read speed is 1.6GB/s.
This is Windows write test using cygwin dd, total speed is around 1.1GB/s
This is Windows read test using cygwin dd, total speed is around 1.6GB/s
This is write test using fio on linux, total speed is around 1.2GB/s
This is read test using dd on linux, total speed is around 1.6GB/s
What's the cause of the speed limit? CPU? motherboard? or PCH chip's ablity?
I don't see anyone else mentioned this issue on internet. Do other X99/C610 motherboard users have the same issue?
If there is anything limiting speed, it is the bottleneck at the DMI bus. You need to remember that the DMI bus is used for a *lot* more things that just SATA - there's PCIe, USB, GFX steering, SPI, I2C, SMBus, LPC (SIO/EC), HDA (Audio), ME, LAN, WiFi (including CNVi), etc.