My Toshiba Notebook WEI Score

.Yesterday I upgraded my RAM to 3GB (from 1.5 GB earlier). I replaced my 'extra' 512 MB RAM with the 2 GB. I wonder how's the performance like since the two RAM sticks are of different capacity (1 GB + 2 GB). Some computer experts consider this as having two different legs that will impair the computer performance. Well, is it really true?

I'm using Toshiba Notebook model Satellite M200 and this was my Windows Experience Index Score after upgrading to 3 GB RAM:

The detail of my Toshiba Notebook System (as on 20 June 2009):
Processor - Intel(R) Core(TM)2 Duo CPU T5450 @ 1.66GHz
Memory (RAM) - 3.00 GB
Graphics - Mobile Intel(R) 965 Express Chipset Family
Gaming graphics - 358 MB Total available graphics memory
Primary hard disk - 91GB Free (143GB Total)
Operating System - Windows Vista (TM) Home Basic
Antivirus - Kaspersky Antivirus 7.0 (Licensed user)

Although my Base Score only improved by 0.1 from the previous 3.4, I really feel my Notebook works much faster than before. The start up and refresh rate are relatively faster. Of course the Windows Experience Index off trust me a little bit, at least it tells how my notebook performs rather than not knowing at all.

By the way, I still wonder how the dual channel rules apply and works best using two identical RAM sticks...