Browsers Loading Slowly

I've been having this issue for a couple of days now. I initially thought it was malware, but seeing as how my system is clear of it, I'm left slightly baffled.

I predominantly use Chrome to web surf, with Firefox as backup. Both have been loading pages at odd intervals, alternating between the normal quickness I'm accustomed to and a snail crawl. I've tried dumping the caches from both browsers manually and running CCleaner to clear up temp files, but so far I've still got the same problems although Chrome's performance has improved a little. I've also checked to see if it was a network connection issue, but all other PCs in my house are running at full speed. Even my laptop with its wireless connection is loading pages in a flash. I'm seriously stumped.

Any ideas?