Scrolling Stutter (since upgrade)

So I have a MBP 5,1 and a couple of days ago I upgraded the RAM from 2GB to 4GB (this kit) and also upgraded from the stock 250GB 5400rpm to a 320GB 7200rpm (this drive).

Every thing is working out good, its faster and more responsive but for some reason it hangs momentarily when I scroll down a web page, which is often, it hangs or sticks very briefly and then resumes scrolling again. It will do it at least once every web page and sometimes 2 or 3 times. It sounds minor but its very aggravating when surfing and scrolling a lot.

I use a wireless Logitech Nano VX mouse with one of those fly wheels that spins so pages scroll according to momentum of the spin so I thought that maybe its the mouse but it also does it when I use the 2 finger scroll on the touchpad.

So it must be either the hard drive or the RAM.Any thoughts? Also is there an OS X equivalent to memtest86+ and HD Tach, so I can run some diagnostics?

HD or RAM, perhaps not - how about safari caches, cron routines, PRAM, as a non techy i would even give SMC a shot. Could even be a Network issue. Just my thoughts.

Firefox does that on my MBP. Safari scrolls smoothly. Are you using Firefox?

I am using firefox, and I just disabled smooth scrolling and all seems well again. I just did a new install of 10.6 (obviously, new hard drive ) so I must have had it disabled before.


Cheers guys