Does Windows ReadyBoost have a meaningful impact on performance?

I was very skeptical, having 6GB of ram on my 8730w laptop running 64bit Windows 7 RC. But, since SD cards is so cheap now, I went out and bought a Panasonic Class 10 (22MB/s) 8GB SD card and put it into my laptop and enabled ReadyBoost. To my surprise, it was quite a noticeable performance gain. One must understand though, that it's a cache kind of performance gain, meaning that you will notice a quite substantial improvement the 2nd, 3rd time you start an application. Nevertheless, I'm most certainly keeping the SD card in my laptop, it's "hidden" away and doesn't stick out like an USB stick.

Yes, it does. You'll see a significant increase in performance whenever the system is I/O bound. Disk-heavy applications like Visual Studio and Apache OpenOffice start up noticeably faster compared to without ReadyBoost—and this is on a system with 8 GB of physical memory!

The most obvious gain in performance I've noticed is when the system resumes from hibernation. My computer has always been unresponsive due to heavy disk activity for the first five or so minutes after resuming, and ReadyBoost produced a vast improvement in system performance and responsiveness during this time.

We just made a detailed comparison on two computers: one with Windows 8.1 and one with Windows 7.

The improvements we measured when enabling ReadyBoost on a system with low amounts of RAM, are the following:

• Opening media files like photos, music or video is slightly faster (approximately by 2%).
• The loading of web pages and the use of Office applications is slightly faster (approximately by 2%).
• Your system's boot timings are improved (up to 7%).
• Your most used applications start faster (by 10 to 15%).

ReadyBoost had no positive impact when playing games or running applications that are CPU or GPU intensive.

You can find the detailed testing procedure plus all the results, here: Does ReadyBoost Work? Does It Improve Performance for Slower PCs?.