I have a solid recommendation for anyone using Moodle on an underpowered server. In fact anyone can use this to increase overall performance!
Everything listed below is free and working with my Moodle 2.2+ installations
I currently use their free service on four Moodle websites and I noticed a dramatic increase in performance.
Performance
- Globally-distributed network
- Secure, redundant DNS
- Anycast routing technology
- Automatic static content caching
- Always Online
Basic security
- Email harvesting protection
- Reputation-based threat protection
- Server side exclude ability
- Hotlinking protection
- Browser integrity checks
- Threat control dashboard
- Block traffic by country or IP range
- Alert infected human visitors
- Identify new threats for community
Control
- Easy DNS management
- Threat challenge page
- Offline browsing page
Analytics
- Stats for all the traffic to your site (threats, search engine crawlers and visitors)
- Outbound link tracking
- Visitor IP geolocation lookup
It never hurts to have extra analytics to review from time to time.
I know performance is always an issue with Moodle and I hope the above helps!