Question about turning write cache on or off

[AirPower4ever]

So I got to reading quite a bit and something just jumped out on me. I am no expert nor have knowledge on this so this is why I am just asking; to get clarity. And maybe too much reading has now crossed my eyes.

So this pertains to SSD's.

If you have SSD's and some have Windows XP on them and the others have Windows 7, in the Device Manager of both systems; if you right click and select "properties" of the SSD and then go to the "Policies" tab I have read that the "Enable write caching on the device" should be checked for Windows 7 machines. I also read that for SSD's with Windows XP on them that this same item should be "unchecked". Is this correct? I mean they perform the same action or am I not reading this right?

I do read for Windows 7 machines that there is an extra box to check which Windows XP does not have and that is the "Turn off Windows write cache buffer flushing on the device". I read that in Windows 7 machines that this should be unchecked. But Windows XP does not have this option box.

So should the "Enable write caching..." be 'on' for both operating systems if they are both on SSD's? What am I missing here, why is Windows 7 have it on and Windows XP off?

Looking forward to the responses, interesting to me.

 

[watdahel]

From my understanding, caching creates an illusion of faster write speed by buffering or caching any written data to system ram, which in effect delays the write process to the drive. To the user its all the same and written data appears to have completed fast. Not really. Windows, decides when to ultimately flush the system cache to the drive. When data is flushed from system ram to the drive, the data is once again cached in the drive's own cache. This time it is the drive that decides when to flush its cache and do the final write. The optional setting in Windows 7 can force Windows to command the drive to flush its cache as well.

So enable the caching and leave uncheck the second box in Windows 7.

 

[AirPower4ever]

Thanks for the response.

So what about for Windows XP, "Enable the caching.." should also be checked if Windows XP is on an SSD?

 

[safelyRemove]

From my understanding, caching creates an illusion of faster write speed by buffering or caching any written data to system ram, which in effect delays the write process to the drive. To the user its all the same and written data appears to have completed fast. Not really. Windows, decides when to ultimately flush the system cache to the drive.

Yes, this is what the setting for optimize for quick removal turns off(vs Performance). Not all drives will show the option.

When data is flushed from system ram to the drive, the data is once again cached in the drive's own cache.

Yes, this is the Enable Write Cache option.

This time it is the drive that decides when to flush its cache and do the final write. The optional setting in Windows 7 can force Windows to command the drive to flush its cache as well.

This part is wrong. When the box is unchecked (or non-existent), the drive can write whenever it likes, in any order it likes, UNTIL Windows says 'now.' When the box is checked, the drive does whatever it wants at all times and Windows does not force it. There is usually critical data the needs to be written just before and just after the flush. The purpose of the flush is to make sure this critical data gets to the disk in proper sequence. Failure to do so can be catastrophic in a power failure or an abrupt removal of the drive.

So enable the caching and leave uncheck the second box in Windows 7.

Yes; the defaults are usually the safe way to go. Only if there is a manufacturer or device-specific recommendation, I would say the advice to turn off write cache for all SSD on XP is wrong. However, it should be noted that USB flash drives often should not have the write cache on, and indeed, don't even allow it. Perhaps there was some confusion between the two types?