High CPU usage and load average in our WordPress blog

Those who frequently visit our site are probably confused by now by the constant change of our blog theme. Until early this week, we were using Brian Gardner’s Revolution Theme which we got as a prize from McBilly‘s contest (thanks again, Mr. Blogger-turned-model!). But for more than three days now, we have been shifting back and forth to the WordPress Default Theme.

The move is meant to isolate the problem related to downtimes in the PMT blog caused by high CPU usage and load averages (see screenshot below). Whenever the CPU usage or the load average peaks, the website stalls because it cannot anymore handle queries.

High CPU usage and load average

By shifting to the Default Theme, we want to know: What’s causing the CPU usage and load average to spike? How can this be solved?

One thing we know, though, is that the spike occurs in the PMT Blog and not in the PMT Forum. Our internal stats also show that more resources are being eaten up by the blog.

Database tables are optimized at least once a week, so we’ve isolated that.

We also disabled some WordPress plugins that require major database queries, such as the Subscribe to Comments and WP-Users Online plugins.

For some reason, when we decided to use the WordPress Default Theme, the CPU usage and load average stats became manageable. That’s not to say, however, that the theme itself causes the spike.

Jaypee told us to look into the plugins associated with the Revolution Theme. Only two plugins come with it — Breadcrumb Navigation XT and Limit Posts plugins — but we don’t think they’re really causing the problem.

And yet everytime we use the Revolution Theme, the site starts to stall again and only after we revert to the Default Theme will the site return to normal. That explains why the blog is using the Default Theme for now.

Upgrading to a Dedicated Server might solve the problem, but we don’t think we’re ready for that yet.

Any other ideas what causes the WordPress blog to register high CPU usage and load averages? And what might be the possible solutions?

Any help is appreciated.

14 thoughts on “High CPU usage and load average in our WordPress blog”

  1. I definitely like the Revolution Theme better than the default; the latter is bland, short of saying its boring. When are you going to get back to the better theme? Anyways, Revolution or default – PMT still rocks!

  2. It seems that you’ve isolated the cause and have fixed the issue since you’re back to using the Revolution theme. So what was it?

    Btw, thanks for the mention and link love. Have a good week! 😀

  3. Hi, Jaypee, honestly, I still have not figured it out. I just decided to revert to the Revolution Theme and will monitor traffic fluctuations to see if and when the problem will be back. If you see the blog sporting the Default Theme again, that means I’m still looking into the problem.

  4. i discovered PMT blog when it was still sporting the template before revolution and i found it easy to use. i think whats important is the contents and how easily it can be accessed.

  5. james, alternatively, you could probably do it the other way around, i.e., try out the newspress themes (wordpress premium themes) or some other version of the revolution theme to determine whether it’s really the theme that’s causing it… if you want to try out and test some revolution themes you can grab some (for FREE) at a new blog which i created http://www.blogmonsterph.com..

    try to see which one fits pmt’s style or approximates the revolution theme you were using before, and maybe you’ll find out if its the theme that’s causing this high cpu usage… i wasn’t able to see which one you used because ngayon lang ulit ako nakadalaw sa blog mo… anyway, goodluck and keep pmt rockin’.

  6. I’m just having exactly the same issue with revolution theme. have you found a good substitute? I like brian’s theme but I just might have to let that one go :/

  7. Great to see research on this. We are seeing a problem w/ a Revolution-based website as well. Literally 100% cpu when the website is on, no visitors.

    Have you finally isolated the issue?

  8. i wasget 3 host suspend my site, and im using wp super chance, and bsuite
    are its make this trouble too?

    .-= Download Area´s latest blog ..[S2M-006] Kou Minefuji – Encore Vol.6 =-.

  9. Extremely very good site thanks so much on your time in writing the posts for all of us to learn about.

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