Comparing GreenCloud SoftBank / IIJ in Tokyo, Japan: evening peak speed tests and international connectivity, detailed test

Testing the GreenCloud SoftBank and IIJ plans bought during the anniversary sale.

Evening-peak mainland China speed tests are in section 4, and international connectivity is in section 5.

Contents

1. Configuration
2. Node Quality
3. itdog test
4. Evening peak speed test
5. International connectivity
6. Summary

1. Configuration

Looking Glass: https://greencloudvps.com/data-centers.php#

🔗 Quick links

2. Node Quality

bash <(curl -sL https://run.NodeQuality.com)

💻Basic information

Softbank	IIJ

🎬IP quality

Softbank	IIJ

🌐Network quality

Softbank	IIJ

📍Return route

Softbank	IIJ

3. TCP Ping（itdog.cn，2025-11-20 23:30）

Both have packet loss and jitter on all three networks. SoftBank has the worst Telecom outbound packet loss and jitter, while IIJ has the worst Unicom outbound packet loss and jitter.

Softbank	IIJ

4. Evening peak proxy speed tests

During evening peak, Telecom on IIJ is stronger than SoftBank; SoftBank Telecom almost drops out. But this is very region-dependent and still far behind optimized routes.
Unicom on SoftBank is okay and has usable speed, while IIJ on Unicom is unusable.
Mobile depends on region. SoftBank can run very fast in some places and almost drops out in others, while IIJ generally cannot get much speed.

🇯🇵 Softbank

[Telecom speed-test records] | [Unicom speed-test records] | [Mobile speed-test records]

🇯🇵 IIJ

[Telecom speed-test records] | [Unicom speed-test records] | [Mobile speed-test records]

5. International connectivity - iPerf3 TCP IPv4 Single-threadspeed test (10 seconds per run, 2025-11-22 20:40-21:40)

Among local Tokyo nodes, SoftBank is generally much faster than IIJ, and speeds to Asia and the US West Coast are also clearly faster. Overall, SoftBank has better international connectivity.

🇯🇵 Softbank

[Test records]

🇯🇵 IIJ

[Test records]

6. Summary

For pure international connectivity, GreenCloud SoftBank is much stronger than IIJ.

If you are buying for direct connection and must choose between these two, pick SoftBank for Mobile/Unicom and IIJ for Telecom. SoftBank on Unicom can basically run; Mobile is pleasant in some places, though Guangdong and Sichuan could not run in the tests. IIJ is basically only pleasant for Telecom in some regions, and in many places it is still throttled to near drop-out during evening peak.

I do not really recommend GreenCloud directly for beginners, because performance is highly region-dependent; someone else's good experience may not be yours.

For Asia-Pacific direct connection, the safer choice may simply be to pay more.

7. About the tests

The machines tested in this article, including all machines used for iPerf3 speed tests, were purchased at my own expense. Results may be time-sensitive.
Kernel parameters of the tested machines (/etc/sysctl.conf) are as follows

fs.file-max = 6815744
net.ipv4.tcp_no_metrics_save=1
net.ipv4.tcp_ecn=0
net.ipv4.tcp_frto=0
net.ipv4.tcp_mtu_probing=0
net.ipv4.tcp_rfc1337=0
net.ipv4.tcp_sack=1
net.ipv4.tcp_fack=1
net.ipv4.tcp_window_scaling=1
net.ipv4.tcp_adv_win_scale=1
net.ipv4.tcp_moderate_rcvbuf=1
net.core.rmem_max=33554432
net.core.wmem_max=33554432
net.ipv4.tcp_rmem=4096 87380 33554432
net.ipv4.tcp_wmem=4096 16384 33554432
net.ipv4.udp_rmem_min=8192
net.ipv4.udp_wmem_min=8192
net.ipv4.ip_forward=1
net.ipv4.conf.all.route_localnet=1
net.ipv4.conf.all.forwarding=1
net.ipv4.conf.default.forwarding=1
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.default.forwarding=1

8. Acknowledgements

Thanks to “Impart Speed Test“(@Kyoma) for providing public-interest speed-test service.