George Wright's Blog: Bit the bullet...

Bit the bullet...

gwright@kde.org (George Wright) — Tue, 08 Jul 2008 22:30:00 +0100

So I buckled under temptation and bought myself a 32GB CF card and a CF-IDE converter board off eBay just now; whole lot came to about 74 pounds including postage, which I think is not too shabby for what should be a fairly good 32GB SSD solution.

Claimed read/write speeds for the card are 36/40MBps which would be very nice if true, but I’m expecting it’ll probably be around half that at best. Still, I’ll do some rudimentary tests with hdparm to see how it is; hopefully it won’t be slower than the 4200rpm 1.8” disk that’s currently in there!

I also hope the battery life improves… I’ve only ever had the X40 down to about 7 or 8W power consumption at minimum; with this setup I hope to inch an extra watt out of it!

"Bit the bullet..." by George Wright

Thu, 10 Jul 2008 09:34:28 +0100

As the adaptor is simply a straight wire converter I’d expect the lack of DMA support is in your CF card rather than the board.

CF revision 4.0 allows for Ultra DMA transfers, but I have no way of telling whether my card is a revision 4 card. They claim read/write speeds of 40/36MBps, and as the fastest PIO mode (6) can only do 25MB/s I’m hoping that means it’s a revision 4 card…

"Bit the bullet..." by Russell

Thu, 10 Jul 2008 05:44:48 +0100

I did exactly this a few months ago. I’ve found that I actually do get a very significant improvement in battery life and noise.

It works very nicely. Sadly, my IDE-CF adapter only supports PIO mode, so large writes really suck. You’ll get fantastic battery life if you avoid large writes on battery; otherwise PIO mode will spike your CPU to 100%, and keep it there until the writing is complete.

The CF card might be low power, but running the CPU at full power will more than make up for it!

"Bit the bullet..." by Luis Gutierrez

Wed, 09 Jul 2008 18:03:54 +0100

thats a good price!

when you get those hdparam results, please post them. I’m interested to see If the performance is anything like a standard 2.5” HD…

In fact, it would be great to have several. One per OS. just change the card, and you have a fresh copy of whatever OS you choose to run!

"Bit the bullet..." by Sacha

Wed, 09 Jul 2008 01:32:33 +0100

That’s sweet! Only 74 pounds? How would you go about opening up your laptop and replacing your hard drive with it? I could save about half a kilo of weight if I did this. Not to mention battery life.

"Bit the bullet..." by Wow

Wed, 09 Jul 2008 01:24:19 +0100

74 pounds? That’s a heavy cf card.

"Bit the bullet..." by George Wright

Wed, 09 Jul 2008 01:11:52 +0100

There also appears to be a ‘standby mode’ for CF cards which only draws about 0.1-0.3mA of current, which is an absolutely negligible current. I suspect the CF enters this mode when not reading/writing.

"Bit the bullet..." by George Wright

Wed, 09 Jul 2008 00:59:48 +0100

A quick search on google suggests that a CF disk draws between 30mA and 100mA when plugged in. At 3.3V that’s only about 0.1W to 0.3W power consumption.

In comparison, Toms Hardware states that 1.8” disks draw 0.3W in idle mode and up to 3W in use.

http://www.tomshardware.com/reviews/1-8-hard-drives-hit-100-gb,1608-3.html

"Bit the bullet..." by pnx.se/jonatan

Wed, 09 Jul 2008 00:05:46 +0100

You might be dissapointed: while traditional hard drives consumes a lot of power while seeking, they are idle most of the time. However, with SSD:s it’s the opposite: seeking is free, but they consume as much power when idle as when active.