What capacity SSD for OS installation?

Not as much difference as I would have thought though, actually. I have a suspicion the CPU-intensive bit is just the compressing, not the decompressing, but might be wrong.
What sort of compression level is it? i.e. how much space are you saving?
 
Thanks for doing the testing JasonM. Be interested to know what a 2.5 C2d would make of that, and also interested in Miniyazz's question re space saving acheived.
 
Yes all compression is more intensive at the compression stage, when you use PKZip the compression always take more time then de-compress.

I have just done a dir /s from root of c: it reports the following.

60,366,435,927 bytes
19,088,207,872 bytes free

This on a 64 SSD drive, however windows reports as 59.6 GB. If you take away the free space thats 40.6 physical space used. 60GB on this, is giving approx 47% extra space due to compression. I'm surprised as would have expected little more, but then it's a boot drive with lots of binaries on it.

Using default windows compression, presume there are settings in register but never looked.

As a side note. The SSD drive should be a little more relialbe, as when i'm writing/reading there is less physical data being moved on the disk compared to compression off.

EDIT I have just realised there is about 1GB of uncompressed data on my SSD drive. This is SQL Server 2008, and also the test file I did last night doh.. So this 1GB of uncompressed data has been mixed in the results, so if anything there should be a 1-2 more %'s to add onto the % extra space above.
 
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Hmm, I make it a compression ratio of about 0.744, or just under 34.5% extra space, a bit off 47%?? Taking into account binary/decimal bases.
Anyway, a fairly decent space saving, and I may consider enabling compression on my laptop SSD next time I reinstall.. as a matter of interest, does it compress properly if you enable it after installation?
 
I'm sure 47% is correct.

I got 19GB extra space for the 40.6GB physical. 40.6 * 1.47 = 60GB (that I manged to store on just 40.6GB).

For example going on above. If I managed to store 81.2GB, I would say I got 100% extra space - 1:2 compression.

Yes you can compress after Windows is installed - it takes time to compress but it's how I do it.
 
a = Total disk size - 59.6GBytes
b = Total free space - 19,088,207,872 bytes = 17.77...GBytes

Therefore c = used space = a - b = 41.82...GBytes

d = Uncompressed space = 60,366,435,927 bytes = 56.22..Gbytes

Therefore extra space = d/c = 1.344.. = 134% (3sf)
Click to expand...

19,088,207,872 is unfortunately not 19GB! Have to divide by 1024 three times to convert to Gibibytes, which is what Windows reports (and is accurate), not divide by 1000 three times, as that gives Gigabytes, and is essentially a con by HDD makers, which is why your 64GB SSD is shown as 59.6GBytes in Windows.
 
Thanks for clearing that up. I knew about dividing by 1024 but never realised it made so much difference to final result untill I worked it out myself.

Still 35% extra space, for no real loss in performance.
 
It is perfectly fine to have just your OS installed to the boot drive, just be careful with where you put your swap space for virtual memory. Put it on a normal HDD if one is available, just so you can lengthen the lifespan of your SSD. The less writing/rewriting you have to do to it, the longer it will live. I personally would only put the OS and maybe a few programs that you need to load extra fast on there. However, go with the 128GB so you have some room to expand in the future. Also, Windows 7 natively supports SSD improvements like the TRIM command and other things. I recommend that you read through the improvements or just try it out using the Windows 7 RC. You could wait until October 22nd though and get the retail, but if you want to start testing it out now you can go pick it up over at TechNet: http://technet.microsoft.com/en-us/windows/dd361745.aspx
 
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