Saturday, February 21, 2009

RAM Disks do not speed up Visual Studio


The limiting factor for Visual Studio is disk IO. I got a tip to speed up Visual Studio from Channel 9 by creating a RAM disk which sounded like a great idea. However, when I ran a thorough set of tests, I found that the performance difference between the Ram disk and the hard disk were not appreciably different. This was a big surprise since RAM is 240,000 times faster than disk (see my previous blog post). But the reason is because Visual Studio and Vista do a lot of caching. So compile times for the same project in RAM disk and on hard disk were pretty similar. I also tested the time it took to search the entire solution for a word, and times to open a solution. There was no discernable difference!


If you still want to try it out and create your own RAM disk, you can download a simple RAMDISK.EXE utility to create a RAM disk in just a few minutes. What is a RAM Disk ?  Ramdisk is a virtual drive created in RAM.


Performance Analysis

Creating files was an average of 1.5 times faster on the RAM disk. reading files was pretty much the same between the two disks. Copying a file was actually slightly slower on the RAM disk. All three visual studio tests were pretty much the same between the two.


What is the downside of a RAM disk?

Running drivers always give the chance of a blue-screen, and I did have one blue screen when I was first setting up the RAMDISK. (My guess is that I chose a non-default RAMDISK size at first. I typed in 200 instead of selecting 256 MB.) So save your stuff before you run the setup.

If your battery falls out or runs out of juice you will loose everything on your RAMDISK, but this rarely happens to my laptop. I always sleep my laptop instead of shutdown, so my data was always there when I woke my laptop up.



Performance Tests

So how much faster is a RAM disk than a standard 5,400 laptop hard disk? I used a simple utility DiskBench to measure disk performance.  The RAM Disk was 1.5 times faster creating files. But very surprisingly, for all other tests, the RAM disk and the hard disk were pretty much the same.



Sorry, a RAM disk isn’t going to help you out much. It doesn’t beat the natural caching of Visual Studio and Vista. Stick to the hard disk. Also, the pain of having to constantly copy a VS solution from the hard disk to the RAM disk means that it is definitely more pain than it is worth. Perhaps moving your temporary IE files folder would be a good application since it creates a lot of files.


Raw performance data.

Note R is the Ramdisk and C is the hard disk. During my test I tried various file sizes ranging from 50 MB to 180 MB. I performed file creation, file reading, and file writing tests. I ran one test against my C drive and then one test against my R drive (ram disk). I shut down all other programs that could potentially compete for IO.

Create File R: C:    
create file 60 MB 272 425   (milliseconds)
create file 60 MB 273 412    
create file 60 MB 206 419    
average: 250.3 418.7 1.7 times faster
create file 180 MB 978 1345    
create file 180 MB 870 1283    
create file 180 MB 945 1344    
average: 931.0 1324.0 1.4 times faster
  R: C:    
create file 192 MB 1034 1484    
create file 192 MB 1002 1427    
create file 192 MB 904 1334    
average: 980.0 1415.0 1.4 times faster
create overall average:     1.5 times faster
Read File R: C:    
read file 201 MB 255 272   (milliseconds)
read file 201 MB 269 249    
read file 201 MB 268 419    
read overall average: 264.0 313.3 1.2 times faster
Copy File R: C:    
copy 50 MB to same dir 144 143   (milliseconds)
copy 50 MB to same dir 150 119    
copy 50 MB to same dir 169 135    
copy 50 MB to same dir 118 121    
copy 50 MB to same dir 129 125    
copy 50 MB to same dir 117 121    
copy 50 MB to same dir 138 121    
copy overall average: 138 126.4 0.92 times faster (slower)
Visual Studio Test R: C:    
open solution with 100 files 5 3   (seconds)
  5 6    
average: 5 4.5   (pretty much the same)
Find word in VS R: C:    
  4 4   (seconds)
  5 5    
average: 4.5 4.5   (pretty much the same)
Run VS project R: C:    
  5 6    
  7 5    
average: 6 5.5   (pretty much the same)

Thursday, February 12, 2009

Highpoint Games


My friend has just started his own board game company, and has released his first game “Greedy Greedy”.

Check it out, this is a game that we had a lot of fun playing many times while in Florida.