The YxVM group said,
"A fair queue has been applied to all VOL plans sharing a 5Gbps port to prevent abuse from congesting the port"
So I tested it. YxVM VOL single-thread return to China Telecom/Unicom is indeed capped below 100Mbps, and Lumen return to China Mobile is also slower than ISIF CM 
| Plan |
🇭🇰 YxVM Volume |
🇭🇰 ISIF HKG-Bs-CM |
| Hardware |
1vCPU, 0.5GB RAM, 10 GB SSD |
1vCPU, 768MB RAM, 20 GB SSD |
| Traffic |
1TB (out) |
2000GB (in+out) |
| Route |
China Mobile via Lumen, Telecom/Unicom via CMI |
China Mobile via Lumen, Telecom/Unicom via CMI |
| Network |
1 x IPv4 + 1 x /64 IPv6 |
1 x IPv4 + 1 x /48 IPv6 |
| Cost |
Monthly USD$ 3.00 |
Monthly EUR€ 6.00 |
💻 Basic Information
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
 |
 |
🎬 IP Quality
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
 |
 |
🌐 Network Quality
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
 |
 |
📍 Return Routes
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
 |
 |
⏬ iPerf3 single-thread TCP speed test (single test, 30 seconds each, 2025-08-19 13:00-14:00)
To reduce the impact of QoS policies on domestic IDC test nodes, this test includes a control group also located in Hong Kong, using 163pp/4837/CMI routes with 1Gbps peak bandwidth
You can see VOL CMI return to Telecom/Unicom is already capped below 100Mbps single-thread. Lumen->CMI return to Mobile is also much lower than ISIF, so it is probably throttled too, just less severely. It also shows that ISIF CM cross-network speeds are decent outside evening peak hours
| Node |
Download from YxVM |
Retransmits |
Average latency |
Download from ISIF |
Retransmits |
Average latency |
Download from control group |
Retransmits |
Average latency |
| Guangdong Mobile 🇨🇳 Yunxi Huanjing @2Gbps |
161Mbps |
60992 |
19.053ms |
636Mbps |
31940 |
22.091ms |
1.03Gbps |
179704 |
18.458ms |
| Wuhan Mobile 🇨🇳 Yunxi Huanjing @2Gbps |
119Mbps |
37492 |
49.874ms |
222Mbps |
632 |
54.020ms |
552Mbps |
1 |
52.077ms |
| Shenzhen Telecom 🇨🇳 Yi'an Cloud @1Gbps |
95.3Mbps |
31590 |
36.223ms |
598Mbps |
20026 |
11.077ms |
870Mbps |
0 |
11.184ms |
| Wuhan Telecom 🇨🇳 Yi'an Cloud @1Gbps |
92.2Mbps |
23764 |
49.065ms |
149Mbps |
23009 |
44.083ms |
520Mbps |
5241 |
45.683ms |
| Ningbo Telecom 🇨🇳 Wuyu Cloud @500Mbps |
94.1Mps |
33297 |
38.598ms |
480Mbps |
0 |
37.805ms |
405Mbps |
522 |
39.077ms |
| Ningbo Telecom 🇨🇳 Seagull Cloud @800Mbps |
92.3Mbps |
37289 |
47.664ms |
278Mbps |
1390 |
33.258ms |
280Mbps |
1563 |
38.568ms |
| Qingdao Unicom 🇨🇳 Yunxi Huanjing @1Gbps |
94.7Mbps |
29890 |
94.627ms |
469Mbps |
44 |
43.252ms |
503Mbps |
0 |
45.042ms |
| Beijing Unicom 9929 🇨🇳 Kuxue Cloud @1Gbps |
155Mbps |
14800 |
40.709ms |
343Mbps |
15 |
47.088ms |
499Mbps |
3 |
41.252ms |
YxVM VOL probably is not throttled in the international direction
| Node |
Upload to YxVM |
Retransmits |
Average latency |
Upload to ISIF |
Retransmits |
Average latency |
| RFC 🇭🇰 T1 JINX |
6.10Gbps |
1283 |
0.679ms |
812Mbps |
1 |
64.110ms |
🇨🇳 Guangdong Mobile Yunxi Huanjing @2Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Wuhan Mobile Yunxi Huanjing @2Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Shenzhen Telecom Yi'an Cloud @1Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Wuhan Telecom Yi'an Cloud @1Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Ningbo Telecom Wuyu Cloud @500Mbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Ningbo Telecom Seagull Cloud @800Mbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Qingdao Unicom Yunxi Huanjing @2Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🇨🇳 Beijing Unicom 9929 Kuxue Cloud @1Gbps
| 🇭🇰 YxVM VOL |
🇭🇰 ISIF CM |
🇭🇰 Control group |
 |
 |
 |
🔗 About The Tests
All machines used in this article were purchased at my own expense; TCP tuning was limited to enabling BBR+FQ, with all other parameters left at defaults; results may be time-sensitive