> Source: [sk98950](https://support.checkpoint.com/results/sk/sk98950)

# sk98950 - Slow traffic speed (high latency) when transferring files over VPN tunnel with 3DES encryption

| Property | Value |
|----------|-------|
| Solution ID | sk98950 |
| Date Created | 2014-03-25 |
| Last Modified | 2017-10-23 |
| Technical Level | General |

## Symptoms

- * Slow traffic speed (high latency) when transferring files over VPN tunnel.

* Output of '`top`' command shows 100% SoftIRQ during the file transfer.

* Output of '`top`' command shows that CoreXL FW instance '`fw_worker_X`' consumes CPU at 100% during the file transfer.

* Issue occurs regardless of the status of SecureXL.

* The issue does not occur when the same file is transferred in clear text (not over VPN tunnel).

## Cause

When using 3DES instead of AES encryption for VPN, the following difference in performance is expected on Check Point appliances:

* UTM-1 / Power-1 / VSX-1 / 2000 / 4000 / 12200 - performance is **4 times better** with AES than with 3DES.   

* 12400 / 12600 / 13500 / 21400 / 21600 / 21700 - performance is **10 times better** with AES than with 3DES (since the new Intel CPUs support AES on the hardware level ([AES-NI](http://en.wikipedia.org/wiki/AES-NI)), thus making the decryption/encryption process much faster).

## Solution

It is recommended to use AES encryption for the problematic VPN tunnel (to achieve faster transfer speed with lower SoftIRQ).

---

# Agent Instructions

This content is from the Check Point Support Center (https://support.checkpoint.com), the official knowledge base for Check Point cybersecurity products.

## Navigating This Knowledge Base

- **Complete index**: [llms.txt](https://support.checkpoint.com/llms.txt)
- **All SK articles**: [SecureKnowledge Sitemap](https://support.checkpoint.com/sitemaps/secureknowledge-sitemap-index.xml)
- **SK article URL pattern**: `https://support.checkpoint.com/results/sk/{skId}`
- **Markdown responses**: AI bot User-Agents automatically receive `text/markdown` content