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AHCI on but not hotswapping

perdomot

Golden Member
I turned on the AHCI in Win7 as per the registry hacks online and the device manager shows the AHCI controllers but the default windows drivers don't detect my external drive via esata when I turn it on. I updated the drivers from the mobo makers website(Asrock AMD 785G) and the hotswapping started to work but when I tested the SSD drive performance with ATTO, there was a drop in performance on the last few tests of 10-25%. When I switched back to the MS drivers, the performance went back up but the hotswapping stopped working. I've heard about AMD having problems with AHCI before so I'm not surprised at the loss of speed but is there a way to get hotswapping enabled without sacrificing speed?
 
You could try a separate PCI or PCI-E hard disk controller card that doesn't use AHCI for hot swap. Silicon Image-based cards can be only $20 and their drivers support hot swap. The only thing that's missing is a "safely remove device" option, but there's third-part software that implement this if you need it. Personally, I just yank the eSATA disk when I'm sure it's finished writing.
 
I did enable ahci in the bios and it does work with the AMD drivers available from the Asrock site. I just don't like the fact that I lose performance for hotswap capability. I do have an Asus usb 3.0/SATA 6G card in my system and tried it but no dice. Do MS ahci drivers not automatically support hotswap?
 
Do MS ahci drivers not automatically support hotswap?

Looks like you need to use the chipset manfgs. drivers to access the AHCI (Advanced Host Controller Interface) features.

On my last AMD board I used a little program called HotSwap.

It may or may not work for you.
 
Actually, I am using Hotswap because I didn't know about the registry trick until a couple of days ago. It works fine but I really wanted to be able to just turn on the external hdd without going through the extra steps.

The AMD drivers are the ones that work and activate hotswapping but they also lose some performance. Granted, at about 175MB/sec reads, I'm not going to notice the difference but I don't like loosing 25MB/sec just to enable a feature that should work. I don't think Intel's drivers have issues like this do they?
 
Actually, I am using Hotswap because I didn't know about the registry trick until a couple of days ago. It works fine but I really wanted to be able to just turn on the external hdd without going through the extra steps.

The AMD drivers are the ones that work and activate hotswapping but they also lose some performance. Granted, at about 175MB/sec reads, I'm not going to notice the difference but I don't like loosing 25MB/sec just to enable a feature that should work. I don't think Intel's drivers have issues like this do they?

What registry trick?
 
I think AMD got its integrated storage controller design from High Point or Promise. At least, both High Point and Promise have variously written or supplied driver code for AMD's chipsets. Seems to me that AMD would have the expertise to do this in-house. Storage controllers aren't all THAT difficult, relative to the complexity of contemporary chipsets, microprocessors, and GPUs.

At any rate, comparative testing show SB700 and SB750 consistently under-performing Intel's ICH9R and ICH10R.
 
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