There are four essential hardware factors which determine the performance of a squid server.

1. Disk Random Seek time:

Because every cache objects is stored on a local disk, the speed to read the data from disk became the most essential factor that impacts the performance of a squid server.

2. System Memory (RAM):

The size of RAM (Random Access Memory) of the computer system ranks in the second essential factor. The minimal RAM size depend on the cache size. For example, if the size of the disk is 1 GB, the minimal RAM needed for caching only is 6 MB. This mean if the other applications need 32 MB that needed RAM size would be 38 MB.

3. Sustained Disk Throughput:

The speed to transfer cache from disk to memory is also another important factor. The higher the speed, the better the performance would be. In this case the interface bus from disk to memory will impacts the transfer speed. Thus a SCSI disk would be preferable than an IDE disk.

4. CPU Power:

The speed of CPU (Central Processing Unit) also impacts squid's performance, but not as important as the other three factors mentioned earlier. In general, one core CPU is sufficient for a squid server. Using a multi-core CPU does not necessarily improve squid's performance.