NIC Throughput Calculator
Compare a NIC's line-rate packet ceiling against what its CPU cores can actually process.
Inputs
Achievable Throughput
10.00Gbit/s
Line-Rate Packet Ceiling
812,744pps
CPU Packet Ceiling
10,080,000pps
Achievable Packet Rate
812,744pps
Binding Constraint
Link line rate
Step by step
Values used
Link speed = 10 Gbit/s; Average frame size = 1,518 bytes; Cores handling packets = 4 cores; Packets per second per core = 1,400,000 pps; Hardware offload enabled (TSO/LRO/RSS) = Yes
NIC Throughput
line-rate pps = link bits/s ÷ ((frame + 20) × 8); achievable pps = min(line rate, cores × pps per core × offload factor).
Achievable Throughput
= 10.00 Gbit/s
Line-Rate Packet Ceiling
= 812,744 pps
CPU Packet Ceiling
= 10,080,000 pps
Achievable Packet Rate
= 812,744 pps
Binding Constraint
= Link line rate
How it works
The link imposes one packet ceiling and the host's packet-processing path imposes another; the achievable rate is the lower of the two, converted back into bits per second. Segmentation and receive-side offloads raise the CPU ceiling by batching per-packet work. A 25 or 100 Gbit/s NIC in a box with too few cores or offloads disabled delivers a fraction of its rating, and the symptom looks like a network fault rather than a host limit.
Formula
NIC Throughput
line-rate pps = link bits/s ÷ ((frame + 20) × 8); achievable pps = min(line rate, cores × pps per core × offload factor).
- frame + 20
- Frame plus preamble and interframe gap
- pps per core
- Packets a single core can process per second
- offload factor
- Uplift from TSO, LRO and RSS (≈1.8×)
Frequently Asked Questions
How is NIC Throughput calculated?
line-rate pps = link bits/s ÷ ((frame + 20) × 8); achievable pps = min(line rate, cores × pps per core × offload factor). The link imposes one packet ceiling and the host's packet-processing path imposes another; the achievable rate is the lower of the two, converted back into bits per second. Segmentation and receive-side offloads raise the CPU ceiling by batching per-packet work.
Why does NIC Throughput matter?
A 25 or 100 Gbit/s NIC in a box with too few cores or offloads disabled delivers a fraction of its rating, and the symptom looks like a network fault rather than a host limit.
What values do I need to enter?
This calculator takes 5 inputs: Link speed, Average frame size, Cores handling packets, Packets per second per core, Hardware offload enabled (TSO/LRO/RSS). The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.