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My SSD (on Windows XP) is working well, however, I get the following strange results from Crystal Mark 2004R3:
236 MB/s for sequential read
59 MB/s for sequential write
168 MB/s for random read 512KB
151 MB/s for random write 512KB
90 MB/s for random read 64KB
89 MB/s for random write 64KB
How it comes that sequential write is much slower than non-sequential? It's only about half as fast as sequential write for my standard HDD. I'm quite sure my partition is properly aligned.
Could anybody post their results? Can anybody explain it?
EDIT
On my SSD, there's a FS with 4kB per cluster and I'm quite sure it's properly aligned, so each cluster corresponds exactly with one sector (a real 4kB sector, not 512B as Windows thinks). Now I see that according to the wikipedia the page size (i.e., the smallest erasable unit) is "often 4–8 kilobytes". The manufacturer doesn't bother with providing the page size in the datasheet.
At least 1/4 of the disk has never been used, so there should be a lot of free blocks allowing the writes to be fast.
EDIT 2
I forgot to say that my drive is Kinston SV100S2/128G.
1What do you mean by non-sequential? You've only posted sequential benchmarks. – sblair – 2011-09-09T23:56:45.970
I get similar results, but with lower sequential write values (probably due to the relatively poor sequential write performance of my X25-M SSD). – sblair – 2011-09-10T00:06:23.877
@sblair: Fixed now. – maaartinus – 2011-09-10T00:55:56.400
Are you running in AHCI or RAID? – Shinrai – 2011-09-12T22:11:14.437
Why XP? 7 does all the SSD-centric optimizations out of the box. – Billy ONeal – 2011-09-12T22:11:24.123
@Shinrai: In BIOS I set RAID mode (but the SSD is not in any RAID). Is it important? – maaartinus – 2011-09-12T22:17:13.133
@Billy ONeal: W7 may do whatever it wants, but I'm not going to try if everything I need works there. My next install will be Linux with XP running in a VM. – maaartinus – 2011-09-12T22:20:37.123
@maartinus - Running in IDE mode is a huge problem for most SSDs. Depending on your RAID controller, AHCI might work better. – Shinrai – 2011-09-12T22:20:40.590
@Shinrai: OK, I'm gonna switch to AHCI as soon as I reinstall and get rid of my fake RAID (which was a really terrible idea). – maaartinus – 2011-09-12T22:28:09.030
1@maartinus - It's also possible AHCI and RAID may perform identically. As long as you're not using IDE or a compatibility mode of some sort. I think XP is likely to be the biggest problem, though. – Shinrai – 2011-09-12T22:32:48.300