TrueCrypt HDD performance without AES-NI?

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iroc409

[H]ard|Gawd
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I have a Sony laptop with a Core i7-740QM CPU that I found out does not have AES-NI (I was hoping, I guess it is just SB chips). Sadly, my machine also does not have a TPM module (for Bitlocker).

Since I travel a fair amount, I would like to encrypt the hard drive. With basically nothing running but background services and an idle Firefox, TrueCrypt benches AES at 280MB/s.

Is this sufficient for me to not really notice a performance drop in Windows if I encrypted the entire drive? It says the performance (predictably) is affected by what the machine is doing. would it be a major impact? 280MB/s is well above what the HDD can support, so it seems this would be a reasonable thought.
 
Why don't you try it? You can decrypt the drive with the rescue CD if you find it too slow.

It runs reasonably fast w/o the AES-NI instruction set.
 
I've been encrypting my laptop HDs with truecrypt for the last 4 years or so. I always use AES, and I've never had a laptop with AES built into the CPU. I almost never notice a difference in performance. The security is certainly worth a small penalty you may pay in performance. I'd be surprised if you notice a performance difference in anything but a benchmark. Give it a shot. Like Justin said, you can always decrypt it and you're right back where you started.

Dave
 
Heh... I have the machine backed up with WHS, it would be pretty quick to test and revert if it didn't work out. Not sure why I didn't think of that. :)

Have you tried using TrueCrypt with a dual-boot Windows/Linux? I know it is possible, just haven't tried it (done several dual boots, though).

I was also thinking about going to a SSD with an external storage drive. I don't really want to do the hassle to be honest, but someone suggested going to a hybrid drive. That seems reasonable, but would the hybrid drive be essentially negated with the encryption? Or worse, would the hybrid drive stored un-encrypted data? I haven't read much on them, other than when they were early in development (and at that time, the theory was the hybrid storage would be separate from the drive itself).
 
It should work fine with dual booting setups.

Don't quote me on this. I think that it is safe to use Truecrypt WDE with a hybrid drive (e.g. Seagate Momentus XT). Any data written to the drive would first be encrypted by CPU and in RAM, then written to the drive. The drive would then buffer to the small SSD and write to the disk platters. Similarly for reading data off the drive...the encrypted data would be read into SSD, then decrypted in RAM and CPU.
 
I've had two laptops (Macs) where I encrypt my home directory. I noticed a significant speed boost when moving from 5400 to 7200 drives (don't have AES-NI).
 
Even a Core 2 Duo (which obviously doesn't have AES-NI) works quite well with Truecrypt full-disk encryption. At least it does on my Thinkpad x200. Your i7 will be fine especially if you're not using an SSD.
 
My laptop currently has a Seagate Momentus XT (hybrid). It works perfectly with truecrypt, but don't waste your money. It's every bit as slow as a traditional spinning platter only HD. I thought it would be a nice compromise between speed and storage space.

You can always decrypt the drive right in the truecrypt software. You don't even need to boot from the rescue disc to do so. I have done this probably 5-7 times and it works perfectly. It does take a while to do, so be prepared for that.

Dave
 
Thanks for the info all, it makes me feel better about it. I'm going to try it out this weekend. I'll just use the machine as-is, if I need to revert WHS will only take a few minutes (other than fussing with some drivers).

dodgeboy said:
My laptop currently has a Seagate Momentus XT (hybrid). It works perfectly with truecrypt, but don't waste your money. It's every bit as slow as a traditional spinning platter only HD. I thought it would be a nice compromise between speed and storage space.

Dave
Click to expand...

Interesting... someone else recommended it. I guess I'll just keep my Samsung 640, or do some more reading. I'm not really unhappy with my laptop's performance for everyday tasks (though I think the Blueray drive is dying.. ugh).
 
So, just to follow up I finally encrypted the drive last night. I have not had a chance to do a ton of work with it yet, but so far notice no detrimental effects of it. It seems to work just fine, with no real performance degradation noticeable. The CPU fan might be running a little higher than usual, but I've been doing a bunch of software updates and so forth, which is more likely the culprit.

I think the next test is to re-install Windows (I guess... is there another way?) and install Ubuntu or something as a dual-boot, and then re-encrypt everything. I chose not to do the drive wipe during encryption, just to save time. When I go back and redo the whole thing, I will do the wipe.
 
If you use an SSD the encryption with Truecrypt using any one of the single cipher algorithms the performance will be nearly seamless on your laptop even without AES-NI. If you cascade them then you'll feel a performance hit.
 
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