compact.exe in a Netbook with a standard 5400RPM drive – the test

If you’ve installed Windows 7 on a netbook, you may have followed the Gizmodo Netbook Guide to do so through a USB memory stick.

In the guide, it’s mentioned that during the install, when it reboots (the first time), you can opt to boot the installer again and run compact.exe on the drive through the Repair/CommandPrompt section.

The idea behind it is that some Netbooks have small SSD’s, and it can save you some space. What about those with large slow standard notebook drives though? Is there any speed increase/advantage?

Here’s where I tried to find out.

The hypothesis is that reading from a notebook drive is generally slow. If you compress the data, there’s less to read on the drive which is good (it should speed things up). The trade-off is that the CPU has to decompress the files as they’re read into memory (which may slow things down).

So how does it work out? Like this:

Blue=standard Red=compact.exe

I apologize for the small text in the key (darn Google Docs…). The blue bars are the results for a default install. The red bars are the results when compact.exe was run on the drive during the install.

More specifically, the times (taken with a stopwatch from the moment I hit enter at the boot menu) were as follows:

Default Install:
51.2 seconds to Desktop (2nd reboot)
51.7 seconds to startup chime (2nd reboot, estimated)

compact.exe Install:
47.1 seconds to Desktop (2nd reboot)
52.3 seconds to startup chime (3rd reboot)

You’ll notice something odd. In the default install, the startup chime came immediately after the desktop showed up. In the compact.exe install, the desktop showed up earlier, but the startup chime was delayed a few seconds. In fact, the chime came up around the same time as the default install.

One thing to note is that compact.exe fragments the files. The hard drive showed as 43% fragmented afterwards! Defragmenting the compacted hard drive may bring the boot times down even more!

Test Method:

This was done on an MSI L1300 Netbook. It looks to be exactly the same as the MSI Wind U130 (specs are the same, and MSI redirects you to the MSI Wind U130’s drivers when you try to grab drivers for the L1300).
Intel Atom N450 (1.66Ghz)
1GB SATA WDC WD1600BEVT-22A23T0 (Western Digital 5400RPM) hard drive
Windows 7 Home Professional 32-bit was the OS used.

It was a fresh install for both scenerios. The netbook was restarted twice after the installation finished. For both restarts, the default install had the startup chime immediately after the desktop showed up, whereas the compact.exe install had the startup chime seconds later (which is why a 3rd restart was done to get an exact reading). Time was taken with a stopwatch program, and should be accurate to within 1/4 second or so.


In hindsight, I should have run additional tests having programs start up at boot. I really wanted to avoid adding variables though (prefetch etc), which is why I did this in a basic boot-only, virgin manner.

It appears that there’s no disadvantage to using compact.exe. At best it shaved a few seconds from the boot time, and at worst was about the same in terms of the start-up chime (well within the margin for error anyway).

If you’re using the N450, or another Atom chip that’s comparable or faster, I’d recommend going through the compact.exe process if using a non-SSD hard drive (a 5400RPM drive anyway).

If you’ve got a slower chip, I’d suggest benchmarking for yourself to see. Remember that decompressing on the fly does use some processor power which might otherwise be going to other start-up tasks.

Again, if using an SSD, it’s almost certainly not worth it speed-wise – the biggest reason here is to reduce the space taken.

Final notes on the compact.exe process:

This is done during install. See the Gizmodo Netbook Article for details.

Running compact.exe took just under an hour on my hard drive.

56155 files were compacted. Size was reduced from 8.7GB to 5.9GB. The overall compression ratio was 1.5:1

compact.exe fragments the files (43% fragmented in my case!). Run disk defragmenter afterwards.