Why are the MB/s of avx and raid6: twice as high for a docked ThinkPad than for an undocked ?

[Toralf FÃrster]

This diff is reliable depending whether the T440s is docked (right) or not (left) :

Linux t44 4.5.7-hardened-r2 #1 SMP Wed Jun 15 23:39:10 CEST 2016 x86_64 Intel(R) Core(TM) i5-4300U CPU @ 1.90GHz GenuineIntel GNU/Linux

215c215
<    avx       : 10196.000 MB/sec
---
>    avx       : 23504.000 MB/sec
225,234c225,234
< raid6: sse2x1   gen()  2578 MB/s
< raid6: sse2x1   xor()  2007 MB/s
< raid6: sse2x2   gen()  3246 MB/s
< raid6: sse2x2   xor()  2203 MB/s
< raid6: sse2x4   gen()  3773 MB/s
< raid6: sse2x4   xor()  2640 MB/s
< raid6: avx2x1   gen()  5042 MB/s
< raid6: avx2x2   gen()  5812 MB/s
< raid6: avx2x4   gen()  6824 MB/s
< raid6: using algorithm avx2x4 gen() 6824 MB/s
---
> raid6: sse2x1   gen()  5816 MB/s
> raid6: sse2x1   xor()  4515 MB/s
> raid6: sse2x2   gen()  7261 MB/s
> raid6: sse2x2   xor()  4968 MB/s
> raid6: sse2x4   gen()  8511 MB/s
> raid6: sse2x4   xor()  5916 MB/s
> raid6: avx2x1   gen() 11378 MB/s
> raid6: avx2x2   gen() 13117 MB/s
> raid6: avx2x4   gen() 15398 MB/s
> raid6: using algorithm avx2x4 gen() 15398 MB/s

And why do the units differ (MB/sec versus MB/s) ?

-- 
Toralf
PGP: C4EACDDE 0076E94E, OTR: 420E74C8 30246EE7