Originally Posted by dellbert
You've got a single stick and the BIOS is reporting dual-channel mode? Is that a read-only field or is that something you can change? It's a mystery to me.
There used to be a lot of studies around on the web showing the % hit rate into the cache based on its size, it was something like this from what I remember:
cache size hit rate
So with a 2MB cache, only 5% of the memory reads come from main memory, and if you make that twice as fast with dual channel, then the increase in performance is half of the 5% or 2.5% faster. That should give you an idea of what is going on here.
With a 2MB cache, you would expect an overall performance increase well below 5%, and likely around 1% or 2%. If you had a 512KB cache or a smaller 128KB cache that are common on previous generation desktop and mobilie processors, then you would be hitting main memory much more often, and could get a 5% to 10% overall increace in performance from the dual channel memory. That isn't going to happen with a 2MB cache in the Pentium M processor. Remember the celeron processors? The main difference was that they had a small 128KB cache instead of 512KB, and that alone slowed them down considerably even though they ran at the same clock speed, and they were sold for less money for entry level computers.