How to calculate PCIe throughput

 gigatransfer bits bits.per.xfer GB.s       enc   enc.GB.s
 1            8    1    8000000000    1 0.9846154  0.9846154
 2            8    2   16000000000    2 0.9846154  1.9692308
 3            8    4   32000000000    4 0.9846154  3.9384615
 4            8    8   64000000000    8 0.9846154  7.8769231
 5            8   16  128000000000   16 0.9846154 15.7538462
 6            8   32  256000000000   32 0.9846154 31.5076923

options(scipen=999)
df=data.frame(gigatransfer=rep(c(8),times=6),bits=2^c(0:5))
df$bits.per.xfer=(df$gigatransfer*10^9)*df$bits
df$GB.s=df$bits.per.xfer/8/1000/1000/1000
df$enc=(128/130)
df$enc.GB.s=df$GB.s*df$enc
print(df)