Comparison of DPC/ISR CPU Usage for Intel EXPI9301CT vs Realtek (Gigabyte MB) NICs

This comparison was run on an HTPC with the following specs:
Motherboard: Gigabyte GA-EP45-UD3R
CPU: Intel E8400 Core2 Duo, 3.0 GHz
RAM: 8 GB
OS: Windows 7 Ultimate
Tuner: Ceton InfiniTV 4 Quad-Tuner PC Card

Other specs, such as storage and GPU have been omitted since this test simply focuses on CPU/DPC/ISR usage with four simultaneous HD recordings using Windows Media Center.  I/O was not a bottleneck and no playback was being performed, locally or via an extender.

While recording four channels, I observed what seemed to be high DPC/ISR usage of the CPU.  I installed an Intel NIC in hopes of improving this situation, but it actually performed slightly worse.  Even if it performed equally or slightly better, I would probably still use the motherboard-based NIC for simplicity and to free a PCIe slot for future use.

The pictures tell the story.  All of the DPC/ISR usage is hitting ndis.sys, since the Ceton InfiniTV 4 provides data through the network interface.

CPU Summary
Realtek

Intel



DPC Details
Realtek

Intel



ISR Details
Realtek

Intel

Special thanks to MagicAndre1981 over at MSFN for his guide to DPC/Interrupt analysis, which was used for this testing:
http://www.msfn.org/board/topic/140263-how-to-get-the-cause-of-high-cpu-usage-by-dpc-interrupt/