actuator

There is a pdf on Zdnet that discusses backup performance and fragmentation...up to 30 % improvement for a defragged volume. Improving Backup Performance with Defragmentation, from Diskeeper - White Papers, Webcasts and Case Studies - ZDNet Mind you, it's a bit dated, but should still be relevant for magnetic HDD systems. At the place I previously used to work part-time, they had the corporate versions of Diskeeper running on some servers. Worked very decently from what I could tell...automatic and all that.

The degree of performance improvement after a defrag would depend on the degree of fragmentation before the defrag. On the whole, I'd think there would be a detectable performance increase after defragmenting a heavily fragmented drive, especially for sequential read/write operations. Atleast, that's what I've noticed generally, but I have not conducted any scientific tests either. From an anecodotal perspective, just last week, i defragmented my sis's year old XP pro laptop (that had never been defragged) and the increase in responsiveness was clearly detectable. Launching Opera used to take 10-15 seconds, but it's now down to 3-4 seconds (rough estimates). And I did not even do a 'proper' defrag, since I used the Windows utility; the PF and MFT are still in 3 or 4 pieces and overall file fragmentation is still 3x% on a 80GB drive.

Apparently automatic defragmentation is the 'hot' thing now, and scheduling a defrag is old and busted. From what my friends* told me, they like auto because once it's installed on the workstations they don't need to waste time scheduling or executing defrags for large numbers of machines weekly. The software uses I/O sensing and runs on unused system cycles, so no supervision required...truly install and forget it. (*they are the IT guys, I am merely a dilettante.)

This may or may not help you: try rolling back the Wi-Fi driver to an older version. My personal Vista Home Premium notebook had a similar problem on my home WLAN after I (mistakenly) updated the Atheros AR5007 driver through Windows update. Vista would not even connect to the WLAN, although the network was perfectly okay (tested by my XP desktop). The only way I could fix it was by uninstalling BOTH the NIC driver as well as the Wifi driver, and reinstalling older versions off the laptop's driver disk. Updating drivers through MS update often seems to create trouble.