USB Ram stick so you can plug it into your USB port and upgrade your system's RAM?
If this is the general idea, forgive me but I do not see much of a market considering 4Gig memory is pretty much standard on any PC/Laptop these days. After than, you'll need to take in considerations the different memory types that exist for all computers. If the clocking of the USB RAM stick is not identical to that of your PC's RAM, it would most probably cause major performance degradation.
But even if you did manage to overcome all these issues, the bandwidth between the CPU and physical RAM would be much greater than that between the system and USB ram stick, so it would ultimately create bottlenecks.....
I have to agree with Chris about the performance issues. The newest USB version 3 (which is still not very common) maxes at 5 Gbit/s. While a DDR3 RAM at a nominal 200Mhz clock rate can do 100 Gbit/s, and at 266Mhz can do around 133Gbit/s. USB speeds are a tiny fraction of RAM's
But sose, you gave me a great idea now. How about trying to redirect the paging file to a USB stick. It should be faster than the hard drive. shouldn't it? Not so sure here. Or is that even possible? I might try that on a test PC
Aaha! now I understand. I was of the mind that since we could make do with an external SATA hard disk, why not an external ram.
But what are the limitations that will prevent the full utilisation of the RAM - processor bandwidth ? I am sure that other device interaction will prevent the attainment of 100gb/s
To get the performance the RAM is close to the processor in architectural terms so that there is very little 'kit' between them. If you used plug-and-play type RAM along the lines of USB or something similar then all the bridge and interface hardware would be in the way. It would crawl, and every time the processor wanted to write to RAM (which is basically all the time) it would get held up waiting