Thats true, which is why the device listed above has it's own battery to keep memory stored for several hours.RAM is volatile, it loses the stuff stored on it when power is turned off
They are very expensive. What you may want to look into actually are SSD (solid-state disks). Which are much, much faster then ordinary hard drives, larger capacities, and are non-volatile.I think gigabyte has a similar device you can buy but it runs off the PCI bus. The hyperdrives (what's linked above) are not cheap (ie £1195.00 for a 16GB max model) and then I think you still have to buy RAM to put in it. https://www.hyperossystems.co.uk/07042003/purchase.htm