Better to get a host with more CPUs or less but more powerful

Question

I'm evaluating some dedicated servers with the aim of possibly moving to them.

One thing that is confusing to me is that there's a big price difference between servers with more CPU's compared to one with less CPUs and more power.

For example, the two packages I am comparing (please note I'm not looking for a recommendation but trying to understand which type is better for webhosting)

AMD Opteron™ 4274 8 Cores x 2.5 GHz (3.5 Turbo Core)

And the

Intel® Xeon® E3-1220 4 Cores x 3.1 GHz (3.4 Turbo Boost)

The rest of the hardware specs as far as I can tell wont have much of an effect on my website. However, I'm confused as to which is better, more cores + slower clock speed, or less cores and faster clock speed.

The Intel one costs about half as much as the AMD one.

Answer 1

Processors with more cores use more advanced technology, that's why they're more expensive. If you add up the processing power, then in theory they're faster, but in practice it depends on you using software that works across multiple cores.

More power won't mean much unless you're running computationally expensive operations. It's hard to judge if that's so without knowing what you're doing; in general, if you're building a webapp then it might be useful, but if your just hosting websites then less so.

CMS platforms often consume a bit of power when they query their database and also some when they render the pages. However, it's often better to look for other ways of speeding up a site, like using caching and CDNs; For example, I'm using the CloudFlair service at the moment and a large amount of requests to my site never actually get near my server.

Using more cores for web hosting usually makes your server able to handle more requests simultaneously; meaning that more people can access your site at the same time without being slowed down. However, as I just mentioned, there are ways of avoiding people hitting your server at all, and other ways to make their visits consume less CPU cycles anyway.

I know you're not looking for a recommendation, but I'll give one anyway! I think you're best off testing your site out on a cloud platform like AWS or Rackspace first; you can try out different sizes and configurations of server without any commitment beyond paying per hour of usage. Once you've decided what's going to work and what your future expansion plans are, you can then decide if it's going to be cheaper to commit to a dedicated server or stay with the flexibility of the cloud.

Answer 2

As Ewan already said. The question is if you can spread the workload over the different cores. If you can then more cores are better. This is under the assumption that you have a lot of concurrent requests. If you have only a few concurrent request but every requests will involve a lot of heavy computing then faster cores are better.

What I would recommend you as well is to check the speed on the bus/backplane/motherboard (whatever you want to call it). Furthermore the cache size can be important too.