Because the price has come down I recently bought a Samsung 840 SSD, and stuck it in my X60 - and then I took it out and put it in my X61, to see what kind of performance gain I get. My X61 has the custom Middleton BIOS and thus has SATA II, and judging by the sustaining readout speed, which is faster than SATA I, it really works. Overall the performance increase in both machines is noticeable although less striking than I expected, but still nice to have. They feel smoother and a bit less jerky.
I took some videos, X60 here
and X61 here
. Screenshots, at roughly the time that I got to the desktop with the fastest of the two:
As you can see the X60 seemed to benefit more - despite having a slower bus - because the X61 was pretty snappy anyway. In both cases installation was easy. The packaging includes some cloning software, which I assume only works with Samsung drives. In both cases the SSD was smaller than the HDD although I had plenty of free space, and the software didn't care about this. The only slightly tricky thing was enabling AHCI in the BIOS, which involved a simple Windows registry alteration. After installing the drive it seemed that I had to run the Windows Experience Index before Windows 8 spotted that it was an SSD. Now, when I run defrag, it does a TRIM operation (and the drive is described as an SSD in the disk manager).
The two machines run at the same heat as before (the machine tries to keep at 40c or below). With the fan turned off they're almost silent, although either the drive or the CPU makes a noticeable high-pitched whining noise.
With 3gb of memory and an SSD I think I've taken the X61 as far as it can go within the bounds of reason - any further upgrades would be more expensive than the machine is worth. The 840 is about £80 in the UK, which isn't far off the used price of an X61. I've read mixed reviews of the 840, mostly criticising its read/write cycle limit. It uses a new type of SSD technology called TLC, which supposedly stands for "The Learning Channel" although it's been years since they showed anything education. Nowadays it's wall-to-wall Honey Boo Boo
which is like the replicants from Blade Runner, e.g. cheap but doomed to die. On the other hand I basically only use it for surfing the internet and running Ableton, neither of which need lots of hard drive space, and so the drives are mostly empty.
It's lighter, too. I'd never held an SSD in my hands before - it felt like a piece of lightweight metal that had fallen off something and weighed about the same as the lid of a coffee jar. Windows 8 fits in about 30gb, so I'd be wary of a 64gb SSD - 120gb good, 250gb better, but uneconomical in the case of the X60.
Also in the screenshots an original Asus Eee 701, with a 4gb(!) SSD, and a Toshiba CDT320, which I think had Puppy Linux on it the last time I turned it on.