Solved Why is HDD speed related to ReadyBoost?

[mjf]

More questions than answers...
I've never bothered with Ready Boost and don't really understand how it could give you much benefit. If you look at the R/W performance of the run of the mill USB flash drive vs a 7200rpm HDD the HDD wins hands down. Most USB flash drives are relatively slow. Run something like CrystalDiskMark on both.
Also, given that RAM is so cheap wouldn't making sure you have 4-8GB RAM be the best approach?
I understand (sort of) how an SSD can improve the performance of your HDD using the likes of Intel Smart Response. But even then isn't the caching ability of your internal RAM better?

 

[whs]

Michael, you have to understand that Ready Boost is a relict of the past. The early Vista systems were sold with 512MB of RAM - 1GB if you were lucky. And RAM was not that chesp in those days.

With a modern PC it certainly makes no sense. Even after upgrading my first Vista PC to 2GB, I threw RB out.

But regarding the speed of the devices - it is not the data transfer speed (where HDDs are certainly faster than sticks) but the access time that makes the difference. Fast access time is also the main reason for SSDs being so fast. Now that is particular to the way the OS works - with small 4K blocks and mostly random reads. For large block data in sequential reads that would be a different story.

 

[Ranger4]

This may help to explain Ready Boost & how it is used. This was copied from the Windows Help files.

Using memory in your storage device to speed up your computer

ReadyBoost can speed up your computer by using storage space on most USB flash drives and flash memory cards. When you plug a ReadyBoost-compatible storage device into your computer, the AutoPlay dialog box offers you the option to speed up your computer using ReadyBoost. If you select this option, you can choose how much memory on the device to use for this purpose.

When you set up a device to work with ReadyBoost, Windows shows you how much space it recommends you allow it to use for optimal performance. For ReadyBoost to effectively speed up your computer, the flash drive or memory card should have at least 1 gigabyte (GB) of available space. If your device doesn't have enough available space for ReadyBoost, you'll see a message telling you to free some space on the device if you want to use it to speed up your system.

You can enable or disable ReadyBoost for a specific flash drive or other removable storage device. For more information, see Turn ReadyBoost on or off for a storage device.

Picture of the ReadyBoost tabThe ReadyBoost tab lets you decide how much storage space on a removable device to use for boosting your system speed.

Show contentHide content What to look for in a flash memory device
Here are some tips on what to look for when selecting a USB flash drive or flash memory card to use with ReadyBoost:

The minimum amount of available space recommended for ReadyBoost to effectively speed up your computer is 1 GB.

For best results, use a flash drive or flash memory card with available space of at least double the amount of memory (RAM) in your computer, and preferably four times as much memory. For example, if your computer has 1 GB of RAM and you plug in a 4 GB USB flash drive, set aside at least 2 GB on the flash drive to get the best performance gain from ReadyBoost, and preferably the entire 4 GB. How much memory you need depends on how you use your computer. Keeping a lot of programs open at once uses more memory.

Give ReadyBoost 2 GB to 4 GB of space for best results on most computers. You can reserve more than 4 GB of space for ReadyBoost on most flash drives and flash memory cards. (Storage devices formatted with the older FAT32 file system can't store more than 4 GB.) You can use a maximum of 32 GB of available space on any single removable storage device with ReadyBoost and up to 256 GB total per computer (by inserting up to eight USB flash drives or flash memory cards into the same computer).

To work with ReadyBoost, a USB flash drive must support USB 2.0 or higher. Your computer must have at least one free USB 2.0 port where you can plug in the flash drive. ReadyBoost works best if you plug the flash drive into a USB port directly on the computer, rather than into an external USB hub shared with other USB devices.

If you want to be sure a USB flash drive works with ReadyBoost, look for a note from the manufacturer that the flash drive is "Enhanced for ReadyBoost." Not all manufacturers list this on their packaging. If there is no mention of ReadyBoost compatibility, the flash drive still might work with ReadyBoost.

There are many different kinds of flash memory cards, such as CompactFlash and Secure Digital (SD) memory cards. Most memory cards work with ReadyBoost. Some SD memory cards don't work well with ReadyBoost due to issues with the SD card interface. ReadyBoost will display a warning message if you attempt to use one of these cards.

Notes
If your computer has a hard disk that uses solid-state drive (SSD) technology, you might not see an option to speed up your computer with ReadyBoost when you plug in a USB flash drive or flash memory card. You may instead receive the message, "Readyboost is not enabled on this computer because the system disk is fast enough that ReadyBoost is unlikely to provide any additional benefit." This is because some SSD drives are so fast they're unlikely to benefit from ReadyBoost.

In some situations, you might not be able to use all of the memory on your device to speed up your computer. For example, some flash memory devices contain both slow and fast flash memory, but ReadyBoost can only use fast flash memory to speed up your computer.

 

[M4dn3ss]

Lots of pointless answers that don't address the question

ReadyBoost is used to improve caching speeds, it is a false popular belief that it provides more RAM or acts as RAM. It primarily uses data in the SuperFetch cache at first, however, later on once all the apportiate ReadyBoost services have been loaded, the Ecache.sys reads all disk I/O to the connected hard-drives, and then begins writing any data from these disk I/Os into a cache file stored on the USB flash drive.

This nails it on the head however. But what exactly is the "cache" in this case? Is it the stuff that gets loaded into SuperFetch? And why does SuperFetch cache to the HDD instead of RAM?

 

[LMiller7]

More questions than answers...
I've never bothered with Ready Boost and don't really understand how it could give you much benefit. If you look at the R/W performance of the run of the mill USB flash drive vs a 7200rpm HDD the HDD wins hands down. Most USB flash drives are relatively slow. Run something like CrystalDiskMark on both.

Conventional drives do indeed have a faster transfer rate than a flash drive. The faster transfer rate will be a benefit when doing large sequential reads. But in most real world situations that just doesn't happen very often in a modern OS. Typical usage patterns are small random reads from multiple files. In that case it is seek time that is more important than transfer rate. The primary performance characteristics are usually seek time, rotation delay, transfer rate. In that order. Typically a hard drive will spend more time seeking data than reading it, and by a considerable margin.

Flash drives have slower transfer rate but much better seek times. ReadyBoost takes advantage of this. When doing small random reads ReadyBoost will read the data from the flash drive if it is present there. This takes advantage of the faster seek time of the flash drive and the slower transfer rate doesn't matter much. But when doing large sequential reads the file system will go directly to the hard drive and bypass the flash drive.

The NT platform has long had an efficient system cache for the hard drive. The problem is that the efficiency of the system varies with the amount of RAM available for the purpose. On systems with limited RAM there just isn't enough for a decent size cache.

ReadyBoost was introduced with Vista that had a minimum RAM specification of 512 MB for the home basic edition. Some time ago I read of ReadyBoost testing on such a system. ReadyBoost significantly improved performance, but upping the RAM to 1 GB helped more. Under favorable conditions ReadyBoost could be of some benefit with as much as 2GB RAM.

ReadyBoost was retained in Windows 7 and Windows 8 for situations where it would be a benefit. But on modern systems with 4 GB RAM and more and with fast conventional or SSD drives it benefits nothing.

 

[whs]

Lots of pointless answers that don't address the question

ReadyBoost is used to improve caching speeds, it is a false popular belief that it provides more RAM or acts as RAM. It primarily uses data in the SuperFetch cache at first, however, later on once all the apportiate ReadyBoost services have been loaded, the Ecache.sys reads all disk I/O to the connected hard-drives, and then begins writing any data from these disk I/Os into a cache file stored on the USB flash drive.

This nails it on the head however. But what exactly is the "cache" in this case? Is it the stuff that gets loaded into SuperFetch? And why does SuperFetch cache to the HDD instead of RAM?

There is still a lot of confusion - e.g. 'caching' that has really nothing to do with it. If there is not enough RAM, then there is no caching. And Ready Boost only comes in when there is not enough RAM.

If you read my post #20, you may understand the mechanism and the speed relationship of sticks and disks in this case.

 

[M4dn3ss]

Ok I'm going to mark this solved then since perhaps only Microsoft truly knows what the hell is going on inside this thing

 

[mjf]

I'm not so sure about pointless answers reference - we are all here to learn as well as generally give solid advice.
Here is a speed test on an external usb HDD vs a bog standard USB flash drive. Ok the read 4k speeds are significantly faster but the write flash speeds are very poor. Maybe the 4k flash read speeds give the gain if you have tiny internal RAM.

 

[Callender]

As far as I can work out HDD speed is in no way related to Readyboost. In other words - using Readyboost doesn't speed up read/ write access. It just allows some frequently used programs to load faster.

On my machine I see no need to use either readyboost or superfetch. I prefer to allocate a chunk of RAM to a persitent RAMdisk. It's configured so that USER temp and WINDOWS temp files are written onto it. This directly relates to HDD speed.

Pagefile is swapped onto a non-windows partition and set to a fixed size of "system recommended plus 200Mb" - the page file on the windows partition is fixed at 16MB only. No need for superfetch.

Screenshot shows Windows partition (C: ) vs RAMdisk (V: ) - an insane speed boost.

 

[LMiller7]

ReadyBoost has everything to do with Disk speed. ReadyBoost is essentially a disk cache. A basic concept of caching is that the media used as the cache, a flash drive, must be faster than the media being cached, the hard drive. RAM is also being used as a disk cache but on low memory systems there just isn't enough. A flash drive has slower transfer rate but seek time is much better. The slower the hard disk the more effective ReadyBoost will be.

The benchmarks shown do indeed favor the RAMDisk by a wide margin. But the numbers have little relevance to real world performance. All modern operating systems has a sophisticated system cache that provide most of the benefits of a RAMDisk with fewer of the problems. If files are frequently accessed then they will be in the cache and the speed of the disk is of no consequence except for the initial read. If files are not frequently why would you want then in the RAMDisk? RAMDisks tend to be a poor use of memory. The OS will usually make better use of it.

A pagefile on a non-system partition will impair performance unless it is also on a separate physical drive.

 

[Callender]

Fragmentation is the keything to consider

The point of swapping the page file onto another partition (for me) is the that file remains contiguous and is therefore written and read fast. Windows usually creates the file as a contiguous entity - assuming that there is enough free contiguous space.

Windows tries to grow the paging file dynamically. This means that the growing and shrinking paging file gets fragmented rapidly and starts decreasing overall performance.

For the above reasons I've found it better to set the page file to a fixed size.

I'd agree that a better performance boost can be had by swapping the page file onto another drive! However I've not needed to do this. I did consider swapping the page file onto Virtual RAM but for system stability reasons I decided against doing this.

As for loading programs - Virtual RAM does essentially the same job as superfetch and so superfetch isn't needed. It actually hinders performance if left enabled on my machine.

 

[LMiller7]

If the initial size of the pagefile is adequate then it will NEVER resize. There will be no continuous resizing, even if the pagefile is system managed. The pagefile will only be resized if this is necessary to prevent exceeding the commit limit. I have confirmed this by observation many times.