My usual running course for testing speed buffs is on Stros M'kai, the stretch of road going between the corner of a low wall between the Port Hunding wayshrine and the corner of a similar wall just that side of Saintsport. I use a digital stopwatch to record times. The starting and the stopping of the stopwatch requires me to let go of the mouse during the last couple of seconds of the sprint.
Using a combo of 5-piece Coward's Gear and 5-piece Fiord's Legacy, I got these times: 35.22 sec, 34.70 sec, 35.27 sec, 34.88 sec
The CG+FL average time is 35.02 ± 0.27
Using a combo of 5-piece Coward's Gear and 5-piece Jailbreaker, I got these times: 35.26 sec, 34.82 sec, 35.13 sec, 35.00 sec
The CG+JB average time is 35.05 ± 0.18
The two combinations give the same speed buff while sprinting, within the margins of error. However, the CG+JB combo gives a measured 8.9% buff to normal movement (it's supposed to be 10% but it isn't, quite), whereas the CG+FL combo gives no buff to speed while trotting along (i.e. not sprinting).
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