En fait le lien sous safari ne donnez rien, j'ai enfin compris que cela ne tournait que sous chrome pour mac.
Voici le résultat après install de chrome.
RTT between client and M-Lab server
15 ms
DOWNLOAD SPEED
60.8 Mbps
UPLOAD SPEED
239.2 Mbps

C'est plus réconfortant. Les mesures sont plus fiables avec ce site?

En fait j'ai  été un peu trop optimiste car il s'agit de Mbps et non de Mo.s.

Le détail ci-après, mais j'avoue que je suis largué là.

Client System Details
OS data:: Mac OS 10.10.2, Architecture: x86
Flash Info: Version = MAC 17,0,0,134
=== Results sent by the server ===

Client System Details
OS data:: Mac OS 10.10.2, Architecture: x86
Flash Info: Version = MAC 17,0,0,134
The slowest link in the end-to-end path is a
a 622 Mbps OC-12 subnet
This connection is receiver limited 24.66% of the time
This connection is network limited 72.30% of the time
622 Mbps OC-12 link found.
Link set to Full Duplex mode
No network congestion discovered.
Good network cable(s) found
Normal duplex operation found.
Web100 reports the Round trip time = 20.74ms
the Packet size = 1440bytes
276 packets retransmitted
1653 duplicate acks received
1259 SACK blocks received
The connection was idle 0.00 seconds (0.00% of the time)
C2S throughput test: Packet queuing detected: 0.29%
S2C throughput test: Packet queuing detected: 0.29%
Web100 reports TCP negotiated the optional Performance Settings to:
RFC 2018 Selective Acknowledgement:
ON
RFC 896 Nagle Algorithm:
ON
RFC 3168 Explicit Congestion Notification:
OFF
RFC 1323 Time Stamping:
ON
RFC 1323 Window Scaling:
ON; Scaling Factors - Server=5, Client=7
The theoretical network limit is 112.18 Mbps
The NDT server has a 1375.36 KByte buffer which limits the throughput to 1036.01 Mbps
Your PC/Workstation has a 1024.00 KByte buffer which limits the throughput to 385.67 Mbps
The network based flow control limits the throughput to 387.70 Mbps
Client Data reports link is OC-12
Client Acks report link is OC-12
Server Data reports link is OC-48
Server Acks report link is OC-12
=== Results sent by the server ===
CurMSS: 1440
X_Rcvbuf: 87380
X_Sndbuf: 2816736
AckPktsOut: 0
BytesRetrans: 397440
CongAvoid: 12246
CongestionOverCount: 0
CongestionSignals: 4
CountRTT: 23389
CurCwnd: 315360
CurRTO: 221
CurRwinRcvd: 1047136
CurRwinSent: 5888
CurSsthresh: 269280
DSACKDups: 0
DataBytesIn: 0
DataBytesOut: 264147904
DataPktsIn: 0
DataPktsOut: 179453
DupAcksIn: 1653
ECNEnabled: 0
FastRetran: 2
MaxCwnd: 1054080
MaxMSS: 1440
MaxRTO: 233
MaxRTT: 43
MaxRwinRcvd: 1048576
MaxRwinSent: 5888
MaxSsthresh: 516960
MinMSS: 1440
MinRTO: 215
MinRTT: 15
MinRwinRcvd: 119552
MinRwinSent: 5792
NagleEnabled: 1
OtherReductions: 1
PktsIn: 25049
PktsOut: 179453
PktsRetrans: 276
RcvWinScale: 7
SACKEnabled: 3
SACKsRcvd: 1259
SendStall: 0
SlowStart: 1275
SampleRTT: 22
SmoothedRTT: 21
SndWinScale: 5
SndLimTimeRwin: 2547562
SndLimTimeCwnd: 7467918
SndLimTimeSender: 313418
SndLimTransRwin: 15
SndLimTransCwnd: 39
SndLimTransSender: 24
SndLimBytesRwin: 112113408
SndLimBytesCwnd: 151049280
SndLimBytesSender: 985216
SubsequentTimeouts: 0
SumRTT: 485155
Timeouts: 0
TimestampsEnabled: 1
WinScaleRcvd: 5
WinScaleSent: 7
DupAcksOut: 0
StartTimeUsec: 944906
Duration: 10328912
c2sData: 6
c2sAck: 6
s2cData: 8
s2cAck: 6
half_duplex: 0
link: 0
congestion: 0
bad_cable: 0
mismatch: 0
spd: 204.59
bw: 112.18
loss: 0.000022290
avgrtt: 20.74
waitsec: 0.00
timesec: 10.00
order: 0.0660
rwintime: 0.2466
sendtime: 0.0303
cwndtime: 0.7230
rwin: 8.0000
swin: 21.4900
cwin: 8.0420
rttsec: 0.020743
Sndbuf: 2816736
aspd: 0.00000
CWND-Limited: -0.10
minCWNDpeak: 4320
maxCWNDpeak: 1054080
CWNDpeaks: 2