Reviewing speedup – from advanced to extreme website acceleration
Yesterday we completely finished with our performance optimization Stage 2 (advanced techniques). Let’s review how much acceleration we have got during this process.
Actual progress
As you can remember we have website load time about 4.2 seconds (clean cache) and the following YSlow chart.
Now we have a bit better situation (with load time about 3.8 seconds).
Minus 29 HTTP requests, minus 25 Kb in size (but please note that we have now 1 banner – about WEBO Site SpeedUp, which is about 10 Kb). So we have achieved about 10% more speedup for new visitors (and about nothing for returned visitors). It seems there is something wrong (we planned to get 20-30% over Stage 1 speedup).
All applied actions, one-by-one:
- Merged, compressed, and delayed JavaScript files. About 6% of speedup.
- Merged and compressed CSS files. About 5% of speedup.
- Applied data:URI, mhtml, and delayed data:URI. About 17% of speedup.
- Used aggressive background images. 4% more speedup.
- Used CSS Sprites. No actual speedup over dataLURI (just more dynamic interface maybe).
- Replaced dynamic images with static ones. Less than 1% speedup.
- Used multiple domains. About 5% more speedup.
A simple sum from these actions gives us 38%, but we have got only 10%. What’s wrong?
Also we have approval picture from Google Webmasters that almost nothing was changed with our WordPress website load speed.
Analyzing drawbacks
Actually a lot of information goes from understanding what actions were applied and what each of them brought to our website. The worst thing here is… data:URI. This technique includes into our CSS file (the second one, with all background images) a lot of excessive base64-encoded data. This was happen due to not properly tuned data:URI usage and bad GD Star Rating plugin behavior (instead of including only required styles to the final CSS file this plugin includes all possible what makes this file much bigger).
But let’s take a look to Page Speed analysis (it’s under Firefox 3.5.7, since 3.6 doesn’t support this plugin yet).
Almost all of yellow (medium warnings) points can give us a little speedup. But ‘Remove unused CSS’ seems to cut our resource CSS file by about 50% (26 Kb). It seems it’s the point – our lost 28% of speedup.
Planning new actions
We are going to improve our website load speed step by step, analyzing and evaluating all possibilities. For now we have tried a lot of different methods and see actual result. Let’s prepare new list of actions with possible acceleration.
- Remove unused CSS. We will get here (due to data:URI usage) about 15% of speedup.
- Server static content from 3rd-party domains (we mentioned 2static.it service, maybe it can help?). About nothing here (less than 1% of speedup).
- Try to combine HTML images on the home page (i.e. just thumbnails) + or move some of them to CSS background. We will save here also about nothing, less than 1%.
- Page Speed also talks about dimensions for our images on the home page. Most of these issues will be fixed with the previous point, but we should somehow measure actual speedup here – we will review how to measure page rendering in browsers.
- Also we should try to apply HTML minify with already gzipped HTML documents. Maybe this will save about 1-2% of load speed.
- …And? Yes, maybe ‘Efficient CSS selectors’. But probably we will leave them for Stage 4. And we will try to add 2-3 Google AdSense blocks to the website and see how they influence our website load speed. And how can they be made unobtrusive (non-blocking, delayed).
OK. It seems we have a great plan for the next week 
Conclusion
Advanced website performance actions can give about 30-50% (after 300% speedup from basic ones), but it will take more time and require more knowledge to use all techniques (i.e. data:URI) properly. And even after all these techniques have been applied you still have some stuff to improve. And we will review it in the next blog posts.
We are going to make our website extreme fast. Are you ready? Fasten your seat belts!
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