Hi, really interesting read, im looking to do similar.
I'm not sure I understand how or where your screenshots demonstrate that your getting 8gb throughput on PCIe 3.0 x1 ?
Given that the specifications on PCIe 3.0 are [email protected] and then halved, [email protected], [email protected], and only [email protected]
The GFX card your using has a max 8Gbps throughput, so your only ever going to achieve a maximum of 4gb on 1x slot?
Any help appreciated, thanks.
He's using the R53SF adapter. The "3" means "PCIe x16". The "5" means "M.2 key A/E" which is PCIe x1. PCIe 3.0 x1 is 8 Gb/s.
You made a couple mistakes in your math. From [email protected], you halved the bandwidth but the link width is quartered. They should both be quartered to get [email protected] I think you mean gigabytes instead of gigabits, so they should be:
32GB/[email protected], 16GB/[email protected], 8GB/[email protected], 2GB/[email protected]
But those bandwidth speeds are for both directions. You need to half them to get single direction bandwidth (for read/write, or Device to Host and Host to Device speeds) like this:
16GB/[email protected], 8GB/[email protected], 4GB/[email protected], 1GB/[email protected]
Multiply them by 128 and divide by 130 to get the actual data rate. 8 Gb/s is 7.876923076923077 Gb/s because encoding on the wire is 128b/130b for PCIe 3.0.
For more info, see https://en.wikipedia.org/wiki/PCI_Express
So the maximum speed in either direction for PCIe 3.0 x1 is: 984.6 MB/s
The number shown by the benchmark is 784.073 MiB/s which is 822.16 MB/s. That is lower than 984.6 MB/s because of PCIe overhead. It's actually a really good portion of the max and you can't expect more than that from any similarly connected PCIe device.
Hello, this is sanjeev, new to egpu, i have hp prodesk 400, need to connect external gpu, please help me with what all i need to buy and where to buy and how to connect.. sorry for bad English