A CDN or Content Delivery Network general works by using a service that provides servers all over the world to quickly deliver media files to the end user cutting down on network latency. This means a CDN benefits your webshop when you have customers from all over the world visiting your shop.
So what you're proposing to do is strictly taken not really a CDN. But that aside there are a couple of things you can do.
- Set up a subdomain that sends as little extra headers as possible (like cookies) along with the images
- Configure NginX on your server to service static files. Since NginX is much faster than Apache this will win you some speed
- Use a service like http://www.jpegmini.com/ to compress your JPEG's further
- Use a different file server for serving images, a general purpose webserver is configured to serve, in this case, PHP pages. A file server will have a different configuration better suited for quickly serving images.
To serve images from a subdomain you will need to do the following: add the subdomain to your DNS (cdn.shirtsofholland.com), add a server alias to your Apache configuration for the existing package where the shop is running on.
ServerAlias cdn.shirtsofholland.com
Forwarding the subdomain to this package, and then in the Magento Backend go to System > Configuration > General > Web > (un)secure url changing the Base media URL to http://cdn.shirtsofholland.com/
The process for your own server is called Domain Sharding. [Update 11jan2017] Since HTTP/2 Domain Sharding has almost no benefit anymore
In case you do want a real CDN, look at a service like OnePica, Magento extension can be found here or Amazone AWS, Using Ashley Schroder tutorial
Both specs you have provided are pretty poor.
The E52420 is an extremely slow, low clock speed CPU, so your page load times will be capped at the speed of a single core at 1.9GHz. The memory is also only 1333, which again will hamper memory access performance. RAID10 is completely unnecessary, the average file size in Magento will not exceed the stripe size on the array, so only a single disk will be serving requests. Not to mention, Magento isn't IO bound, so you'll get no gains from it.
If speed is remotely important, that machine is a very poor choice.
The second machine isn't really worth talking about. A single consumer grade SSD and single HDD provides no redundancy or reliability in a failure scenario. There's also not nearly enough RAM.
For 5,000 unqiues per day, you require around 16 cores for consistent performance. Memory wise, you should maintain a ratio of around 2GB/Core, so 32GB minimum.
There's some good reading on sizing and selection here,
But the most important consideration is not just hardware selection, that will dictate the best speed, but not necessarily the final speed.
For example. If you misconfigure an extremely fast server, you will likely have performance that matches the slow server above (if that was properly configured).
So hardware selection absolutely goes hand in hand with server configuration. Once you have obtained the right hardware, it needs to be properly configured to perform at peak levels.
Configuring a server properly is NOT just installing Varnish and hiding poor speed behind it, it is not just installing Redis and hoping that the default configuration will actually offer you any benefits over file based caching, it is not just installing the Percona flavour of MySQL because you read it was faster. The list can go on and on, but a fast Magento server is not made up of the software you install on it, it is how you configure, tune and refine the software level configuration of each individual component.
Again, that doesn't mean copy and pasting a blog article or even Magento white paper conf. snippet. It means understanding the software, what the change in settings mean for your store, does it resolve your bottleneck etc.
Which brings me on to say, when picking your hosting provider, pick one that knows what hardware is going to fit your stores requirements (ie. they should ask detailed questions about your store during presales), pick one that wholly focuses on Magento - and most importantly, pick one that will do a free demo of your store on their solution. With the final point, you can see for yourself, whether your speed is acceptable or not, and a good provider will be able to tell you if there is further gains to be had in your store (and NOT by suggesting a cache).
Your question shouldnt be "What hardware do I need", it should be "What hosting provider is going to fully cater to my needs as a merchant, who will fully manage and take ownership of server planning and configuration, so I can focus on what I do, selling goods on my store".
Best Answer
MageStack has a good tool to test Magento sites.
Also, any online tool you might use will be enough since both tests will be done using the same criteria and because of that, both tests will be comparable against each other.