I have a Lenovo W510 laptop including 8GB RAM, Samsung SSD, and "Intel 82577LM Gigabit Network Connection" Ethernet adapter with what I believe are the latest available drivers. This machine was recently built (with SSD) and Win7. The machine connects to a Dlink Ethernet switch, to which is also connected a NAS box and Router (with connection to the Internet).
The machine and network configuration is capable of good performance, including:
- copy large file from the NAS to desktop at > 40 MByte/sec
- download from internet speed test site at > 30Mbit/sec
But after use (of various time lengths, typically minutes to hours...), the following happens:
- copy of large file runs 6 - 10 MB/sec
- I can detect a reduced "snappiness" in File Explorer operation;
- web site browsing becomes "painful". Curiously, internet speed tests still show circa 30 Mbit/s download speed.
A restart of the computer generally rectifies the problem (for a time). At all times, the "test tools" on the Intel card report good quality network connections, good quality cable and cable lengths in the 20-30 m range (depending on connection I use) and no problems.
I have connected to the Dlink switch on various ports - makes no difference.
I have another (more power desktop) machine using a Realtek LAN card - it experiences no such difficulties and performs very well consistently.
I am stumped by this. Can anyone offer any explanation or solution?