Intel RST caching: Slow write speeds

imrazor

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I have an WD Green 2TB drive being cached by an Intel 330 60GB SSD. When testing the WD drive with Crystal Disk Mark I'm seeing 350MB/s read speeds, which is good enough for me. However, the write speeds are oddly low. I'm seeing 70MB/s sequential write speeds when trying to write out to the drive. Before setting up the drive with RST, I benchmarked it at 130MB/s sequential write speed. Another oddity is USB3 external drive speed. I tried to copy about 30GB to a Seagate USB 3 drive from the WD drive and the write speed fluctuated all over the place, until finally settling down to 5MB/s (that's not a typo.) I booted up Linux, and was able to copy the same files off of the WD at a good clip (between 70MB/s and 110MB/s).

Does anyone have any idea what could be going on here? I've tried "Enhanced" and "Maximized" acceleration and saw no improvement in write speed. Can't trust Maximized mode anyway, due to frequent storms.
 
So when I enable Intel SSD caching I'm supposed to expect a DROP of 60MB/s sequential write speed?? Really don't think so. Please link me to some published benchmarks...

EDIT: Well I did some testing and it looks like the Intel 330 is indeed a turd when it comes to write speed with uncompressable data. I turned off caching, disabled caching mode and turned the 330 into a regular, empty drive. I then ran Crystal Disk Mark on the new, blank drive. With uncompressable data I got a sequential write speed of a blazing 70MB/s. When I wrote all 1's to the SSD, I got a much more impressive 400MB/s. Funny thing is when the drive was in cache mode, and I wrote easily compressible data to the cached drive, I *still* saw 70MB/s. Frustrating...