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I've just set up a new Z68 system, and since I had a spare SSD lying around from when I upgraded my netbook I figured I'd give SRT a shot. As it's an older SSD it's only on a 3Mbps port (highest xfer rate it supports), whereas the HDD it's caching (WD Blue 1Tb) is on a 6Mbps port being SATA3.

Ideally, I'd have a SATA3 SSD caching the HDD, but as it stands now should I see any performance increases? I've heard SRT takes a bit to get rolling properly, and so far I haven't noticed a particular increase in responsiveness. My current SRT mode is maximum, meaning the SSD is first port of call for writes, which then writes back to the HDD when it has a chance.

Explicit Question: Should I expect any performance increase when using SRT with a SATA2 SSD caching a SATA3 HDD, or might I be better served by the "traditional" approach of manually allocating certain programs to the SSD.

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Are you sure that 3Mbps and 6Mbps are the correct values, didn't you mean 3Gbps and 6Gbps? – Zoredache Aug 30 '11 at 23:58
Yep, did mean G bps not Mbps... For some reason my autocorrect wants me to slow down considerably ;) – malleus Aug 31 '11 at 0:25
Seriously, noone wants to weigh in on the question rather than the nomenclature? – malleus Aug 31 '11 at 3:24
Don't add tags if you don't need to (the ones you put are fine). Even a SATA-II SSD will have well over double the transfer rate of the HDD (not to mention 100 times lower seek times), so you should definitely be noticing some performance increases. However, I don't understand what you're actually asking here. This is a Q&A website, edit your question to have a more explicit question or it will be closed. – Breakthrough Aug 31 '11 at 13:57
Thanks Breakthrough, that's the sort of info I was after. The lower seek time is good to hear, and I have been noticing a more responsive disk over the past few hours. I'm fairly sure I'll keep on with SRT from the info you've given. – malleus Aug 31 '11 at 15:06

Should I expect any performance increase when using SRT with a SATA2 SSD caching a SATA3 HDD [...]

It doesn't matter if your HDD is SATA 2 or SATA 3, since most hard drives max out at less then the SATA 2 max bus speed (300 MB/s), it only applies if you are using RAID-0 or a SATA 3 solid-state drive.

You should (obviously) expect a performance increase using SRT technology, that's the whole purpose of it. The SSD not only has a faster transfer speed, but it has drastically reduced file seek times. The point of SRT is to allow the SSD to cache frequently used files (or parts of files) so they can be seeked and read quickly, while the HDD head moves to the file to begin reading (mitigating the seek time of the hard drive).

Whether or not you notice this effect depends on your needs, but during times of short, random file writes/reads (e.g. loading programs or an operating system, compiling a program), you will most certainly notice a speedup.

[...] or might I be better served by the "traditional" approach of manually allocating certain programs to the SSD?

Making mention of the SRT versus traditional approach, going purely with a solid-state drive is faster then using SRT for the reasons I mentioned above. It's not being used as a cache, it's being used as the drive, so you get the sustained high transfer rates as well as very low seek times for every single file on the drive.

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