Question: I have a 4GB RAM 500GB 7200 rpm HDD laptop and when I hibernate the laptop it takes in the region of 3 or 4 minutes(\*) to hibernate. not the 24 seconds it used to take.

It takes this long whether or not my external USB drives are plugged in.

When I got it it was pre-installed with Vista Home Premium, I have since restored the OS from the backup DVD's I created, and also upgraded to Vista Ultimate.

What should I be checking in order to track down the source of this rather sloth-like hibernate process.

I'm looking to tips, techniques and tools please peeps.

Thanks in advance.

I will be back to update / answer this question as I investigate, and also if I find a solution.

(\*) Timed it - it took 4 minutes 38 seconds.
31 seconds after enabling disk write caching

Answer: 
Some advice for speeding hibernation:

1. See if there are any suspicious events in the Event Log.
2. Disable Readyboost and Superfetch (if enabled).
3. Run Windows Update, paying attention to optional driver updates.
4. Check new versions for non-Microsoft drivers and especially for display, bluetooth, USB.
5. Download [TweakVista](http://www.stardock.com/products/tweakvista/) - it may tell you which parts of the system are affecting sleep/hibernation performance
6. Remove the hibernation file by switching the feature off and defrag your primary drive (ensure you have at least 20% disk space free), then re-enable hibernation.
When you hibernate (go into a suspend-to-disk state) your OS needs to write copies of data in any active memory pages in RAM to disk (to the hibernation file in the root of your system drive usually in Windows) - in your case that could mean writing up to 4Gb of information to disk.

Writing 4Gb in three minutes is an average of just under 22Mbyte/second which while a good chunk slower than most modern drives can write isn't outrageously so it is unlikely that Windows has decided to run your drive in PIO mode, but it might be worth checking to see if it is using an old standard DMA mode instead of the shine newer UDMA modes your drive will support. Windows should drop the standard down a step or few in the presence of certain drive anomalies, though I've also seen it do this for no readily apparent reason. In case it has dropped the standard down (you can check this, and try revert, in the device manager entry for the drive controller) for good reason I suggest you get some software that can read the SMART properties of the drive to make sure it still thinks it is healthy.

A quick question (which might be a little patronising in which case I'm sorry!): are you sure that you were hibernating (suspend to disk) before rather than sleeping (suspend to RAM)? Though I would expect suspend-to-RAM to be quicker than 24 seconds, writing a full 4Gb of state in 24 seconds is ~170Mbyte/second on average which seems a mite high. I could be barking up the wrong end of the stick here as there are reasons why a susend-to-disk can be much faster (not all RAM in use, recently un-hibernated so most of the hibernation file is still valid and doesn't need to be rewritten (assuming Windows uses a one-to-one mapping for RAM pages to file blocks and uses a mark-on-access-and-only-write-if-dirty algorithm when hibernating, etc...)