A CacheDrive's hard drive is used for caching and for the device's operating system. The amount of available cache depends on the size of the hard drive. The approximate size of the cache will be the size of the hard drive minus the amount reserved for the operating system.
Physical Devices (G80, G40, etc.)
| Hard Drive Size (GB) | Reserved for OS |
| < 200 | 16 |
| < 400 | 32 |
| < 800 | 64 |
| < 1600 | 96 |
| >= 1600 | 192 |
Virtual Devices (V202, etc.)
| Hard Drive Size (GB) | Reserved for OS | Notes |
| < 32 | 16 | Fixed |
| 32 to 128 | 16 to 48 | Linearly increasing |
| 128 to 512 | 48 to 96 | Linearly increasing
|
| 512 to 2048 | 96 to 192 | Linearly increasing
|
| > 2048 | 192 | Fixed |
