FancyCache Demo - Fully Utilizes OS Invisible Memory on 32-bit Windows

As is well known, 32-bit Windows desktop operating systems only use 2.75~3.5GB physical memory even though users have 4GB or more of RAM installed. The part of memory, which OS can't use, is called OS Invisible Memory. Now FancyCache can utilize it as a cache to the volume/disk, supplementary to the Windows file caching scheme. Below is a comparison experiment to verify the performance.

Test Platform:
    Motherboard: GA-EP43-DS3LR
    CPU: DualCore Intel Core 2 Duo E7400, 2800 MHz
    Hard disk: WDC WD1600BB-55GUC0(ATA-100, 160GB, 7200RPM, cache: 2MB)
    RAM: 2GB x3, DDR2-800 SDRAM
    OS: Microsoft Windows 7 Ultimate (32bit)

Test Environment:
In order to make the result sensible, here we build up a high-load running environment where some large-scale applications are running simultaneously and the available memory has only about 500MB left.

Experiment A: FancyCache is not activated, and we do the following steps,

Step 1. Copy file fa which size is about 1G from a volume (here is E) to another volume (here is F). Windows' file cache manager caches file fa in the available memory.

Step 2. Copy file fb which size is about 800MB from a volume (here is E) to another volume (here is D). This step makes Windows' file cache manager caches file fb and discards the old cache data of file fa because of limited available memory for cache.

Step 3. Now copy the file fa from volume F to volume D. Because the cache data of file fa has been discarded, the copy progress is slow and it takes about 75 seconds to finish the copy.

Experiment B: Activate FancyCache on volume F.
(Level-I Cache: RAM 128MB, Level-II Cache: Invisible Memory 1024MB)

Step 4. Do step 2 again to make Windows' file cache manager discards the cache data acquired in step 3. This makes the comparison experiments to be done under the same conditions.

Step 5. Repeat step 1~3 to do the comparison experiment. Now we can see that although Windows' file cache manager discards the cache data of file fa, FancyCache still cache data for file fa. Thus the copy progress is faster than that of Experiment A. It takes about 40 seconds to finish the copy.

The above experiments also show that Windows aims to cache all data while FancyCache aims to data user specifies, which might reach a higher cache hit-rate.