CPU Sizing

There are two figures you need to bear in mind when choosing a server, concurrency and page load time. Concurrency is how many customers your server can support at any time. Individual page load time is how fast the page actual loads for a single customer.

It is possible to have:

  1. A slow page load time and low concurrency support (low clock speed CPU (GHz), few cores)
  2. A fast page load time, but low concurrency support (high clock speed CPU (GHz), few cores)
  3. A slow page load time, but high concurrency support (low clock speed CPU (GHz), lots of cores)
  4. A fast page load time and high concurrency support (high clock speed CPU (GHz), lots of cores)

You can choose your hardware based on this.

Concurrency

  1. A standard Magento demo store is capable of delivering roughly 230 uniques per GHz, per hour.
  2. A typical web store, with admin user activity, development activity, product addition/deletion can see this degrade by around 100%, to 115 uniques per GHz, per hour.
  3. A store with a poorly built/heavy template can further reduce the figure by another 100-200%, to 50 uniques per GHz, per hour.

We quote estimate figures based on a combination of 2. and 3. - but you can adjust to suit your store's build quality.

Chassis Total GHz Visitors/Hour Peak Visitors/Day Peak Concurrent Visitors Peak Sustained Visitors/Day
8-Core 28 1,610 16,100 187 4,025
16-Core 83.2 4,784 47,840 555 11,960
28-Core 72.8 4,186 41,860 485 10,465
32-Core 92.8 5,336 53,360 619 13,340
40-Core 120 6,900 69,000 800 17,250
56-Core 145.6 8,372 83,720 971 20,930
64-Core 166.4 9,568 95,680 1,109 23,920
384-Core 844.8 4,8576 485,760 5,632 121,440

The total GHz figure can be obtained by multiplying the CPU clock speed against the number of logical cores.

Individual Page load time

A standard Magento demo store (CE or EE – with all caches disabled) is capable of achieving average load times of:

Chassis CPU Speed* Page Load Time (seconds)
8-Core 3.5 0.480
16-Core 3.3 0.509
28-Core 3.5 0.480
32-Core 2.9 0.579
40-Core 3.6 0.467
56-Core 3.5 0.480
64-Core 3 0.560
384-Core 3.4 0.494

But again, a badly built/heavy template will cause this figure to increase exponentially. When we quote figures, we use the demo store template with sample data as an example.

* As Sonassi use the latest generation Intel server CPUs, the CPU speed quoted is that of the maximum sustained frequency the CPU can operate at