---
title: "W5500 module communication speed"
url: "https://maker.wiznet.io/forum/15707"
markdown_url: "https://maker.wiznet.io/forum/15707/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "yaewonbae"
created: "2025-04-22T13:34:10+09:00"
last_activity: "2025-04-23T09:35:37+09:00"
language: "en"
views: 11
replies: 1
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# W5500 module communication speed

## Question

Asked by yaewonbae on 2025-04-22 in Ethernet Chips.

When I install an LTE modem on the w5500 module, the internet speed is very slow.
It takes more than 10 seconds to download a 250 Kbytes file. When I connect an LTE modem to a computer, the speed is fast.
Is there a solution?

## Replies

### Reply 1 by Hannah, 2025-04-23

Hi, yaewonbae.

1.What is the intended use case for combining the W5500 and LTE modem?

First, I’m curious about the purpose behind using the W5500 in combination with an LTE modem.
Typically, the W5500 is used with low-power Ethernet-based MCUs and is often paired with low-speed communication networks like **Cat M1, NB-IoT, or LoRa**.
However, if you're combining it with a **high-speed LTE modem**, I'd like to understand what kind of scenario or data transmission requirements you're targeting.

2. SPI communication delays are likely affecting the overall speed.

While the W5500 operates quickly at the Ethernet level, the **SPI interface between the W5500 and the MCU can become a bottleneck**.

- If the SPI clock speed is too low,

- If communication is handled using polling,

- Or if you're not using DMA or interrupt-based transfers,

then the **SPI throughput may be significantly slower than the LTE network speed**, which can directly impact the overall transmission rate.

3. It’s important to verify the Ethernet port speed provided by the LTE modem.

Additionally, you should check whether the **Ethernet port on your LTE modem actually supports 100Mbps (Fast Ethernet)** or **1Gbps (Gigabit Ethernet)**.
This can have a significant effect on throughput, especially if you're expecting high-speed data transfers over LTE.

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Source: https://maker.wiznet.io/forum/15707