In message <[EMAIL PROTECTED]>, Nicholas A. Sinnott-Armstrong writes:
> --- Dieter wrote:
> For 2 GiB can you just add main memory? I haven't priced memory recently,
> but 2 years ago 2 GiB of ECC DDR400 was US$248 including shipping. That's
> less than the engadget adapter you reference and I assume the adapter doesn't
> include the flash. They make mainboards that can take lots of memory.
> (Tyan for example.)
> --- end of quote ---
>
> RAM is much cheaper these days. At least for Macs, DDR667 1GB SODIMMs
> are around $48 these days, which makes it even more reasonable.
Is that for ECC? Poking around for current prices, I find
Kingston 1GiB DDR400 ECC $67.90
ACP-EP 1GiB DDR667 ECC $62.99
Corsair 1GiB DDR2-667 ECC $89.95
> I do like the idea of the flash drive/RAM hard drive. While I don't really
> care
> to have one, I think that many others would like to "reap the performance
> benefits" (which I don't really see in the USB flash drive model, but is very
> true of the RAM HD).
If the USB thingy is anything like the USB-to-SATA bridges, they will be slow.
My USB-to-SATA bridge maxes out at 15 MB/s. Same disk can do up to ~70 MB/s
when connected directly to the chipset controller.
> We could set up ODG1 to act as a RAM HD to see if this is worth it, then
> design
> a different board with a *much* smaller, cheaper FPGA and more RAM.
Sounds easy enough. But is there a big enough market for such a board?
JRT> For this to fly, you need something which is faster than your disk and
JRT> cheaper than main memory RAM. IT would be best if it was as fast as the
JRT> fastest disks available for desktops -- 320 MB/s for SCSI.
320 MB/s is the speed of the bus, You aren't going to get data on/off the
platters that fast. 7200 rpm 3.5" SATA does about 40-70 MB/s, so figure about
2.08x
that for 15Krpm SCSI with the same platter diameter and density, so about
83-145 MB/s.
To get a solution that is less expensive than adding mainboard RAM you'd need to
find a version of RAM that is a *lot* less expensive than whatever your
mainboard
needs, since you have the cost of the board, connectors, the glue logic, etc.
A low volume board isn't going to be $5-10. And you lose a slot. And it will
be a lot slower than main memory.
The usual solutions:
more main memory
swap partitions on multiple disks
locate swap partitions at the fast end of the disks
JRT> With 1GB, my system works quite well using only a little swap unless you
JRT> do something that needs a lot of memory like working on a large image in
JRT> GIMP.
You need 2-16 GiB of very fast swap for gimp? The working set is that big?
Either you have a VERY large image or gimp is a world class pig.
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